1 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
2
3 // Copyright (C) 2010-2023 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/functional_hash.h> // for __is_fast_hash
36 #include <bits/stl_algobase.h> // for std::min, std::is_permutation.
37 #include <bits/stl_pair.h> // for std::pair
38 #include <ext/aligned_buffer.h> // for __gnu_cxx::__aligned_buffer
39 #include <ext/alloc_traits.h> // for std::__alloc_rebind
40 #include <ext/numeric_traits.h> // for __gnu_cxx::__int_traits
41
42 namespace std _GLIBCXX_VISIBILITY(default)
43 {
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
45 /// @cond undocumented
46
47 template<typename _Key, typename _Value, typename _Alloc,
48 typename _ExtractKey, typename _Equal,
49 typename _Hash, typename _RangeHash, typename _Unused,
50 typename _RehashPolicy, typename _Traits>
51 class _Hashtable;
52
53 namespace __detail
54 {
55 /**
56 * @defgroup hashtable-detail Base and Implementation Classes
57 * @ingroup unordered_associative_containers
58 * @{
59 */
60 template<typename _Key, typename _Value, typename _ExtractKey,
61 typename _Equal, typename _Hash, typename _RangeHash,
62 typename _Unused, typename _Traits>
63 struct _Hashtable_base;
64
65 // Helper function: return distance(first, last) for forward
66 // iterators, or 0/1 for input iterators.
67 template<typename _Iterator>
68 inline typename std::iterator_traits<_Iterator>::difference_type
69 __distance_fw(_Iterator __first, _Iterator __last,
70 std::input_iterator_tag)
71 { return __first != __last ? 1 : 0; }
72
73 template<typename _Iterator>
74 inline typename std::iterator_traits<_Iterator>::difference_type
75 __distance_fw(_Iterator __first, _Iterator __last,
76 std::forward_iterator_tag)
77 { return std::distance(__first, __last); }
78
79 template<typename _Iterator>
80 inline typename std::iterator_traits<_Iterator>::difference_type
81 __distance_fw(_Iterator __first, _Iterator __last)
82 { return __distance_fw(__first, __last,
83 std::__iterator_category(__first)); }
84
85 struct _Identity
86 {
87 template<typename _Tp>
88 _Tp&&
89 operator()(_Tp&& __x) const noexcept
90 { return std::forward<_Tp>(__x); }
91 };
92
93 struct _Select1st
94 {
95 template<typename _Pair>
96 struct __1st_type;
97
98 template<typename _Tp, typename _Up>
99 struct __1st_type<pair<_Tp, _Up>>
100 { using type = _Tp; };
101
102 template<typename _Tp, typename _Up>
103 struct __1st_type<const pair<_Tp, _Up>>
104 { using type = const _Tp; };
105
106 template<typename _Pair>
107 struct __1st_type<_Pair&>
108 { using type = typename __1st_type<_Pair>::type&; };
109
110 template<typename _Tp>
111 typename __1st_type<_Tp>::type&&
112 operator()(_Tp&& __x) const noexcept
113 { return std::forward<_Tp>(__x).first; }
114 };
115
116 template<typename _ExKey, typename _Value>
117 struct _ConvertToValueType;
118
119 template<typename _Value>
120 struct _ConvertToValueType<_Identity, _Value>
121 {
122 template<typename _Kt>
123 constexpr _Kt&&
124 operator()(_Kt&& __k) const noexcept
125 { return std::forward<_Kt>(__k); }
126 };
127
128 template<typename _Value>
129 struct _ConvertToValueType<_Select1st, _Value>
130 {
131 constexpr _Value&&
132 operator()(_Value&& __x) const noexcept
133 { return std::move(__x); }
134
135 constexpr const _Value&
136 operator()(const _Value& __x) const noexcept
137 { return __x; }
138
139 template<typename _Kt, typename _Val>
140 constexpr std::pair<_Kt, _Val>&&
141 operator()(std::pair<_Kt, _Val>&& __x) const noexcept
142 { return std::move(__x); }
143
144 template<typename _Kt, typename _Val>
145 constexpr const std::pair<_Kt, _Val>&
146 operator()(const std::pair<_Kt, _Val>& __x) const noexcept
147 { return __x; }
148 };
149
150 template<typename _ExKey>
151 struct _NodeBuilder;
152
153 template<>
154 struct _NodeBuilder<_Select1st>
155 {
156 template<typename _Kt, typename _Arg, typename _NodeGenerator>
157 static auto
158 _S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
159 -> typename _NodeGenerator::__node_type*
160 {
161 return __node_gen(std::forward<_Kt>(__k),
162 std::forward<_Arg>(__arg).second);
163 }
164 };
165
166 template<>
167 struct _NodeBuilder<_Identity>
168 {
169 template<typename _Kt, typename _Arg, typename _NodeGenerator>
170 static auto
171 _S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
172 -> typename _NodeGenerator::__node_type*
173 { return __node_gen(std::forward<_Kt>(__k)); }
174 };
175
176 template<typename _NodeAlloc>
177 struct _Hashtable_alloc;
178
179 // Functor recycling a pool of nodes and using allocation once the pool is
180 // empty.
181 template<typename _NodeAlloc>
182 struct _ReuseOrAllocNode
183 {
184 private:
185 using __node_alloc_type = _NodeAlloc;
186 using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
187 using __node_alloc_traits =
188 typename __hashtable_alloc::__node_alloc_traits;
189
190 public:
191 using __node_type = typename __hashtable_alloc::__node_type;
192
193 _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
194 : _M_nodes(__nodes), _M_h(__h) { }
195 _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
196
197 ~_ReuseOrAllocNode()
198 { _M_h._M_deallocate_nodes(_M_nodes); }
199
200 template<typename... _Args>
201 __node_type*
202 operator()(_Args&&... __args) const
203 {
204 if (_M_nodes)
205 {
206 __node_type* __node = _M_nodes;
207 _M_nodes = _M_nodes->_M_next();
208 __node->_M_nxt = nullptr;
209 auto& __a = _M_h._M_node_allocator();
210 __node_alloc_traits::destroy(__a, __node->_M_valptr());
211 __try
212 {
213 __node_alloc_traits::construct(__a, __node->_M_valptr(),
214 std::forward<_Args>(__args)...);
215 }
216 __catch(...)
217 {
218 _M_h._M_deallocate_node_ptr(__node);
219 __throw_exception_again;
220 }
221 return __node;
222 }
223 return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
224 }
225
226 private:
227 mutable __node_type* _M_nodes;
228 __hashtable_alloc& _M_h;
229 };
230
231 // Functor similar to the previous one but without any pool of nodes to
232 // recycle.
233 template<typename _NodeAlloc>
234 struct _AllocNode
235 {
236 private:
237 using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
238
239 public:
240 using __node_type = typename __hashtable_alloc::__node_type;
241
242 _AllocNode(__hashtable_alloc& __h)
243 : _M_h(__h) { }
244
245 template<typename... _Args>
246 __node_type*
247 operator()(_Args&&... __args) const
248 { return _M_h._M_allocate_node(std::forward<_Args>(__args)...); }
249
250 private:
251 __hashtable_alloc& _M_h;
252 };
253
254 // Auxiliary types used for all instantiations of _Hashtable nodes
255 // and iterators.
256
257 /**
258 * struct _Hashtable_traits
259 *
260 * Important traits for hash tables.
261 *
262 * @tparam _Cache_hash_code Boolean value. True if the value of
263 * the hash function is stored along with the value. This is a
264 * time-space tradeoff. Storing it may improve lookup speed by
265 * reducing the number of times we need to call the _Hash or _Equal
266 * functors.
267 *
268 * @tparam _Constant_iterators Boolean value. True if iterator and
269 * const_iterator are both constant iterator types. This is true
270 * for unordered_set and unordered_multiset, false for
271 * unordered_map and unordered_multimap.
272 *
273 * @tparam _Unique_keys Boolean value. True if the return value
274 * of _Hashtable::count(k) is always at most one, false if it may
275 * be an arbitrary number. This is true for unordered_set and
276 * unordered_map, false for unordered_multiset and
277 * unordered_multimap.
278 */
279 template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
280 struct _Hashtable_traits
281 {
282 using __hash_cached = __bool_constant<_Cache_hash_code>;
283 using __constant_iterators = __bool_constant<_Constant_iterators>;
284 using __unique_keys = __bool_constant<_Unique_keys>;
285 };
286
287 /**
288 * struct _Hashtable_hash_traits
289 *
290 * Important traits for hash tables depending on associated hasher.
291 *
292 */
293 template<typename _Hash>
294 struct _Hashtable_hash_traits
295 {
296 static constexpr std::size_t
297 __small_size_threshold() noexcept
298 { return std::__is_fast_hash<_Hash>::value ? 0 : 20; }
299 };
300
301 /**
302 * struct _Hash_node_base
303 *
304 * Nodes, used to wrap elements stored in the hash table. A policy
305 * template parameter of class template _Hashtable controls whether
306 * nodes also store a hash code. In some cases (e.g. strings) this
307 * may be a performance win.
308 */
309 struct _Hash_node_base
310 {
311 _Hash_node_base* _M_nxt;
312
313 _Hash_node_base() noexcept : _M_nxt() { }
314
315 _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
316 };
317
318 /**
319 * struct _Hash_node_value_base
320 *
321 * Node type with the value to store.
322 */
323 template<typename _Value>
324 struct _Hash_node_value_base
325 {
326 typedef _Value value_type;
327
328 __gnu_cxx::__aligned_buffer<_Value> _M_storage;
329
330 _Value*
331 _M_valptr() noexcept
332 { return _M_storage._M_ptr(); }
333
334 const _Value*
335 _M_valptr() const noexcept
336 { return _M_storage._M_ptr(); }
337
338 _Value&
339 _M_v() noexcept
340 { return *_M_valptr(); }
341
342 const _Value&
343 _M_v() const noexcept
344 { return *_M_valptr(); }
345 };
346
347 /**
348 * Primary template struct _Hash_node_code_cache.
349 */
350 template<bool _Cache_hash_code>
351 struct _Hash_node_code_cache
352 { };
353
354 /**
355 * Specialization for node with cache, struct _Hash_node_code_cache.
356 */
357 template<>
358 struct _Hash_node_code_cache<true>
359 { std::size_t _M_hash_code; };
360
361 template<typename _Value, bool _Cache_hash_code>
362 struct _Hash_node_value
363 : _Hash_node_value_base<_Value>
364 , _Hash_node_code_cache<_Cache_hash_code>
365 { };
366
367 /**
368 * Primary template struct _Hash_node.
369 */
370 template<typename _Value, bool _Cache_hash_code>
371 struct _Hash_node
372 : _Hash_node_base
373 , _Hash_node_value<_Value, _Cache_hash_code>
374 {
375 _Hash_node*
376 _M_next() const noexcept
377 { return static_cast<_Hash_node*>(this->_M_nxt); }
378 };
379
380 /// Base class for node iterators.
381 template<typename _Value, bool _Cache_hash_code>
382 struct _Node_iterator_base
383 {
384 using __node_type = _Hash_node<_Value, _Cache_hash_code>;
385
386 __node_type* _M_cur;
387
388 _Node_iterator_base() : _M_cur(nullptr) { }
389 _Node_iterator_base(__node_type* __p) noexcept
390 : _M_cur(__p) { }
391
392 void
393 _M_incr() noexcept
394 { _M_cur = _M_cur->_M_next(); }
395
396 friend bool
397 operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
398 noexcept
399 { return __x._M_cur == __y._M_cur; }
400
401 #if __cpp_impl_three_way_comparison < 201907L
402 friend bool
403 operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
404 noexcept
405 { return __x._M_cur != __y._M_cur; }
406 #endif
407 };
408
409 /// Node iterators, used to iterate through all the hashtable.
410 template<typename _Value, bool __constant_iterators, bool __cache>
411 struct _Node_iterator
412 : public _Node_iterator_base<_Value, __cache>
413 {
414 private:
415 using __base_type = _Node_iterator_base<_Value, __cache>;
416 using __node_type = typename __base_type::__node_type;
417
418 public:
419 using value_type = _Value;
420 using difference_type = std::ptrdiff_t;
421 using iterator_category = std::forward_iterator_tag;
422
423 using pointer = __conditional_t<__constant_iterators,
424 const value_type*, value_type*>;
425
426 using reference = __conditional_t<__constant_iterators,
427 const value_type&, value_type&>;
428
429 _Node_iterator() = default;
430
431 explicit
432 _Node_iterator(__node_type* __p) noexcept
433 : __base_type(__p) { }
434
435 reference
436 operator*() const noexcept
437 { return this->_M_cur->_M_v(); }
438
439 pointer
440 operator->() const noexcept
441 { return this->_M_cur->_M_valptr(); }
442
443 _Node_iterator&
444 operator++() noexcept
445 {
446 this->_M_incr();
447 return *this;
448 }
449
450 _Node_iterator
451 operator++(int) noexcept
452 {
453 _Node_iterator __tmp(*this);
454 this->_M_incr();
455 return __tmp;
456 }
457 };
458
459 /// Node const_iterators, used to iterate through all the hashtable.
460 template<typename _Value, bool __constant_iterators, bool __cache>
461 struct _Node_const_iterator
462 : public _Node_iterator_base<_Value, __cache>
463 {
464 private:
465 using __base_type = _Node_iterator_base<_Value, __cache>;
466 using __node_type = typename __base_type::__node_type;
467
468 public:
469 typedef _Value value_type;
470 typedef std::ptrdiff_t difference_type;
471 typedef std::forward_iterator_tag iterator_category;
472
473 typedef const value_type* pointer;
474 typedef const value_type& reference;
475
476 _Node_const_iterator() = default;
477
478 explicit
479 _Node_const_iterator(__node_type* __p) noexcept
480 : __base_type(__p) { }
481
482 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
483 __cache>& __x) noexcept
484 : __base_type(__x._M_cur) { }
485
486 reference
487 operator*() const noexcept
488 { return this->_M_cur->_M_v(); }
489
490 pointer
491 operator->() const noexcept
492 { return this->_M_cur->_M_valptr(); }
493
494 _Node_const_iterator&
495 operator++() noexcept
496 {
497 this->_M_incr();
498 return *this;
499 }
500
501 _Node_const_iterator
502 operator++(int) noexcept
503 {
504 _Node_const_iterator __tmp(*this);
505 this->_M_incr();
506 return __tmp;
507 }
508 };
509
510 // Many of class template _Hashtable's template parameters are policy
511 // classes. These are defaults for the policies.
512
513 /// Default range hashing function: use division to fold a large number
514 /// into the range [0, N).
515 struct _Mod_range_hashing
516 {
517 typedef std::size_t first_argument_type;
518 typedef std::size_t second_argument_type;
519 typedef std::size_t result_type;
520
521 result_type
522 operator()(first_argument_type __num,
523 second_argument_type __den) const noexcept
524 { return __num % __den; }
525 };
526
527 /// Default ranged hash function H. In principle it should be a
528 /// function object composed from objects of type H1 and H2 such that
529 /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
530 /// h1 and h2. So instead we'll just use a tag to tell class template
531 /// hashtable to do that composition.
532 struct _Default_ranged_hash { };
533
534 /// Default value for rehash policy. Bucket size is (usually) the
535 /// smallest prime that keeps the load factor small enough.
536 struct _Prime_rehash_policy
537 {
538 using __has_load_factor = true_type;
539
540 _Prime_rehash_policy(float __z = 1.0) noexcept
541 : _M_max_load_factor(__z), _M_next_resize(0) { }
542
543 float
544 max_load_factor() const noexcept
545 { return _M_max_load_factor; }
546
547 // Return a bucket size no smaller than n.
548 std::size_t
549 _M_next_bkt(std::size_t __n) const;
550
551 // Return a bucket count appropriate for n elements
552 std::size_t
553 _M_bkt_for_elements(std::size_t __n) const
554 { return __builtin_ceil(__n / (double)_M_max_load_factor); }
555
556 // __n_bkt is current bucket count, __n_elt is current element count,
557 // and __n_ins is number of elements to be inserted. Do we need to
558 // increase bucket count? If so, return make_pair(true, n), where n
559 // is the new bucket count. If not, return make_pair(false, 0).
560 std::pair<bool, std::size_t>
561 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
562 std::size_t __n_ins) const;
563
564 typedef std::size_t _State;
565
566 _State
567 _M_state() const
568 { return _M_next_resize; }
569
570 void
571 _M_reset() noexcept
572 { _M_next_resize = 0; }
573
574 void
575 _M_reset(_State __state)
576 { _M_next_resize = __state; }
577
578 static const std::size_t _S_growth_factor = 2;
579
580 float _M_max_load_factor;
581 mutable std::size_t _M_next_resize;
582 };
583
584 /// Range hashing function assuming that second arg is a power of 2.
585 struct _Mask_range_hashing
586 {
587 typedef std::size_t first_argument_type;
588 typedef std::size_t second_argument_type;
589 typedef std::size_t result_type;
590
591 result_type
592 operator()(first_argument_type __num,
593 second_argument_type __den) const noexcept
594 { return __num & (__den - 1); }
595 };
596
597 /// Compute closest power of 2 not less than __n
598 inline std::size_t
599 __clp2(std::size_t __n) noexcept
600 {
601 using __gnu_cxx::__int_traits;
602 // Equivalent to return __n ? std::bit_ceil(__n) : 0;
603 if (__n < 2)
604 return __n;
605 const unsigned __lz = sizeof(size_t) > sizeof(long)
606 ? __builtin_clzll(__n - 1ull)
607 : __builtin_clzl(__n - 1ul);
608 // Doing two shifts avoids undefined behaviour when __lz == 0.
609 return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
610 }
611
612 /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
613 /// operations.
614 struct _Power2_rehash_policy
615 {
616 using __has_load_factor = true_type;
617
618 _Power2_rehash_policy(float __z = 1.0) noexcept
619 : _M_max_load_factor(__z), _M_next_resize(0) { }
620
621 float
622 max_load_factor() const noexcept
623 { return _M_max_load_factor; }
624
625 // Return a bucket size no smaller than n (as long as n is not above the
626 // highest power of 2).
627 std::size_t
628 _M_next_bkt(std::size_t __n) noexcept
629 {
630 if (__n == 0)
631 // Special case on container 1st initialization with 0 bucket count
632 // hint. We keep _M_next_resize to 0 to make sure that next time we
633 // want to add an element allocation will take place.
634 return 1;
635
636 const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
637 const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
638 std::size_t __res = __clp2(__n);
639
640 if (__res == 0)
641 __res = __max_bkt;
642 else if (__res == 1)
643 // If __res is 1 we force it to 2 to make sure there will be an
644 // allocation so that nothing need to be stored in the initial
645 // single bucket
646 __res = 2;
647
648 if (__res == __max_bkt)
649 // Set next resize to the max value so that we never try to rehash again
650 // as we already reach the biggest possible bucket number.
651 // Note that it might result in max_load_factor not being respected.
652 _M_next_resize = size_t(-1);
653 else
654 _M_next_resize
655 = __builtin_floor(__res * (double)_M_max_load_factor);
656
657 return __res;
658 }
659
660 // Return a bucket count appropriate for n elements
661 std::size_t
662 _M_bkt_for_elements(std::size_t __n) const noexcept
663 { return __builtin_ceil(__n / (double)_M_max_load_factor); }
664
665 // __n_bkt is current bucket count, __n_elt is current element count,
666 // and __n_ins is number of elements to be inserted. Do we need to
667 // increase bucket count? If so, return make_pair(true, n), where n
668 // is the new bucket count. If not, return make_pair(false, 0).
669 std::pair<bool, std::size_t>
670 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
671 std::size_t __n_ins) noexcept
672 {
673 if (__n_elt + __n_ins > _M_next_resize)
674 {
675 // If _M_next_resize is 0 it means that we have nothing allocated so
676 // far and that we start inserting elements. In this case we start
677 // with an initial bucket size of 11.
678 double __min_bkts
679 = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
680 / (double)_M_max_load_factor;
681 if (__min_bkts >= __n_bkt)
682 return { true,
683 _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
684 __n_bkt * _S_growth_factor)) };
685
686 _M_next_resize
687 = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
688 return { false, 0 };
689 }
690 else
691 return { false, 0 };
692 }
693
694 typedef std::size_t _State;
695
696 _State
697 _M_state() const noexcept
698 { return _M_next_resize; }
699
700 void
701 _M_reset() noexcept
702 { _M_next_resize = 0; }
703
704 void
705 _M_reset(_State __state) noexcept
706 { _M_next_resize = __state; }
707
708 static const std::size_t _S_growth_factor = 2;
709
710 float _M_max_load_factor;
711 std::size_t _M_next_resize;
712 };
713
714 // Base classes for std::_Hashtable. We define these base classes
715 // because in some cases we want to do different things depending on
716 // the value of a policy class. In some cases the policy class
717 // affects which member functions and nested typedefs are defined;
718 // we handle that by specializing base class templates. Several of
719 // the base class templates need to access other members of class
720 // template _Hashtable, so we use a variant of the "Curiously
721 // Recurring Template Pattern" (CRTP) technique.
722
723 /**
724 * Primary class template _Map_base.
725 *
726 * If the hashtable has a value type of the form pair<const T1, T2> and
727 * a key extraction policy (_ExtractKey) that returns the first part
728 * of the pair, the hashtable gets a mapped_type typedef. If it
729 * satisfies those criteria and also has unique keys, then it also
730 * gets an operator[].
731 */
732 template<typename _Key, typename _Value, typename _Alloc,
733 typename _ExtractKey, typename _Equal,
734 typename _Hash, typename _RangeHash, typename _Unused,
735 typename _RehashPolicy, typename _Traits,
736 bool _Unique_keys = _Traits::__unique_keys::value>
737 struct _Map_base { };
738
739 /// Partial specialization, __unique_keys set to false, std::pair value type.
740 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
741 typename _Hash, typename _RangeHash, typename _Unused,
742 typename _RehashPolicy, typename _Traits>
743 struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
744 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
745 {
746 using mapped_type = _Val;
747 };
748
749 /// Partial specialization, __unique_keys set to true.
750 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
751 typename _Hash, typename _RangeHash, typename _Unused,
752 typename _RehashPolicy, typename _Traits>
753 struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
754 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
755 {
756 private:
757 using __hashtable_base = _Hashtable_base<_Key, pair<const _Key, _Val>,
758 _Select1st, _Equal, _Hash,
759 _RangeHash, _Unused,
760 _Traits>;
761
762 using __hashtable = _Hashtable<_Key, pair<const _Key, _Val>, _Alloc,
763 _Select1st, _Equal, _Hash, _RangeHash,
764 _Unused, _RehashPolicy, _Traits>;
765
766 using __hash_code = typename __hashtable_base::__hash_code;
767
768 public:
769 using key_type = typename __hashtable_base::key_type;
770 using mapped_type = _Val;
771
772 mapped_type&
773 operator[](const key_type& __k);
774
775 mapped_type&
776 operator[](key_type&& __k);
777
778 // _GLIBCXX_RESOLVE_LIB_DEFECTS
779 // DR 761. unordered_map needs an at() member function.
780 mapped_type&
781 at(const key_type& __k)
782 {
783 auto __ite = static_cast<__hashtable*>(this)->find(__k);
784 if (!__ite._M_cur)
785 __throw_out_of_range(__N("unordered_map::at"));
786 return __ite->second;
787 }
788
789 const mapped_type&
790 at(const key_type& __k) const
791 {
792 auto __ite = static_cast<const __hashtable*>(this)->find(__k);
793 if (!__ite._M_cur)
794 __throw_out_of_range(__N("unordered_map::at"));
795 return __ite->second;
796 }
797 };
798
799 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
800 typename _Hash, typename _RangeHash, typename _Unused,
801 typename _RehashPolicy, typename _Traits>
802 auto
803 _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
804 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
805 operator[](const key_type& __k)
806 -> mapped_type&
807 {
808 __hashtable* __h = static_cast<__hashtable*>(this);
809 __hash_code __code = __h->_M_hash_code(__k);
810 std::size_t __bkt = __h->_M_bucket_index(__code);
811 if (auto __node = __h->_M_find_node(__bkt, __k, __code))
812 return __node->_M_v().second;
813
814 typename __hashtable::_Scoped_node __node {
815 __h,
816 std::piecewise_construct,
817 std::tuple<const key_type&>(__k),
818 std::tuple<>()
819 };
820 auto __pos
821 = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
822 __node._M_node = nullptr;
823 return __pos->second;
824 }
825
826 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
827 typename _Hash, typename _RangeHash, typename _Unused,
828 typename _RehashPolicy, typename _Traits>
829 auto
830 _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
831 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
832 operator[](key_type&& __k)
833 -> mapped_type&
834 {
835 __hashtable* __h = static_cast<__hashtable*>(this);
836 __hash_code __code = __h->_M_hash_code(__k);
837 std::size_t __bkt = __h->_M_bucket_index(__code);
838 if (auto __node = __h->_M_find_node(__bkt, __k, __code))
839 return __node->_M_v().second;
840
841 typename __hashtable::_Scoped_node __node {
842 __h,
843 std::piecewise_construct,
844 std::forward_as_tuple(std::move(__k)),
845 std::tuple<>()
846 };
847 auto __pos
848 = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
849 __node._M_node = nullptr;
850 return __pos->second;
851 }
852
853 // Partial specialization for unordered_map<const T, U>, see PR 104174.
854 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
855 typename _Hash, typename _RangeHash, typename _Unused,
856 typename _RehashPolicy, typename _Traits, bool __uniq>
857 struct _Map_base<const _Key, pair<const _Key, _Val>,
858 _Alloc, _Select1st, _Equal, _Hash,
859 _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
860 : _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal, _Hash,
861 _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
862 { };
863
864 /**
865 * Primary class template _Insert_base.
866 *
867 * Defines @c insert member functions appropriate to all _Hashtables.
868 */
869 template<typename _Key, typename _Value, typename _Alloc,
870 typename _ExtractKey, typename _Equal,
871 typename _Hash, typename _RangeHash, typename _Unused,
872 typename _RehashPolicy, typename _Traits>
873 struct _Insert_base
874 {
875 protected:
876 using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
877 _Equal, _Hash, _RangeHash,
878 _Unused, _Traits>;
879
880 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
881 _Hash, _RangeHash,
882 _Unused, _RehashPolicy, _Traits>;
883
884 using __hash_cached = typename _Traits::__hash_cached;
885 using __constant_iterators = typename _Traits::__constant_iterators;
886
887 using __hashtable_alloc = _Hashtable_alloc<
888 __alloc_rebind<_Alloc, _Hash_node<_Value,
889 __hash_cached::value>>>;
890
891 using value_type = typename __hashtable_base::value_type;
892 using size_type = typename __hashtable_base::size_type;
893
894 using __unique_keys = typename _Traits::__unique_keys;
895 using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
896 using __node_gen_type = _AllocNode<__node_alloc_type>;
897
898 __hashtable&
899 _M_conjure_hashtable()
900 { return *(static_cast<__hashtable*>(this)); }
901
902 template<typename _InputIterator, typename _NodeGetter>
903 void
904 _M_insert_range(_InputIterator __first, _InputIterator __last,
905 const _NodeGetter&, true_type __uks);
906
907 template<typename _InputIterator, typename _NodeGetter>
908 void
909 _M_insert_range(_InputIterator __first, _InputIterator __last,
910 const _NodeGetter&, false_type __uks);
911
912 public:
913 using iterator = _Node_iterator<_Value, __constant_iterators::value,
914 __hash_cached::value>;
915
916 using const_iterator = _Node_const_iterator<_Value,
917 __constant_iterators::value,
918 __hash_cached::value>;
919
920 using __ireturn_type = __conditional_t<__unique_keys::value,
921 std::pair<iterator, bool>,
922 iterator>;
923
924 __ireturn_type
925 insert(const value_type& __v)
926 {
927 __hashtable& __h = _M_conjure_hashtable();
928 __node_gen_type __node_gen(__h);
929 return __h._M_insert(__v, __node_gen, __unique_keys{});
930 }
931
932 iterator
933 insert(const_iterator __hint, const value_type& __v)
934 {
935 __hashtable& __h = _M_conjure_hashtable();
936 __node_gen_type __node_gen(__h);
937 return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
938 }
939
940 template<typename _KType, typename... _Args>
941 std::pair<iterator, bool>
942 try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
943 {
944 __hashtable& __h = _M_conjure_hashtable();
945 auto __code = __h._M_hash_code(__k);
946 std::size_t __bkt = __h._M_bucket_index(__code);
947 if (auto __node = __h._M_find_node(__bkt, __k, __code))
948 return { iterator(__node), false };
949
950 typename __hashtable::_Scoped_node __node {
951 &__h,
952 std::piecewise_construct,
953 std::forward_as_tuple(std::forward<_KType>(__k)),
954 std::forward_as_tuple(std::forward<_Args>(__args)...)
955 };
956 auto __it
957 = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
958 __node._M_node = nullptr;
959 return { __it, true };
960 }
961
962 void
963 insert(initializer_list<value_type> __l)
964 { this->insert(__l.begin(), __l.end()); }
965
966 template<typename _InputIterator>
967 void
968 insert(_InputIterator __first, _InputIterator __last)
969 {
970 __hashtable& __h = _M_conjure_hashtable();
971 __node_gen_type __node_gen(__h);
972 return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
973 }
974 };
975
976 template<typename _Key, typename _Value, typename _Alloc,
977 typename _ExtractKey, typename _Equal,
978 typename _Hash, typename _RangeHash, typename _Unused,
979 typename _RehashPolicy, typename _Traits>
980 template<typename _InputIterator, typename _NodeGetter>
981 void
982 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
983 _Hash, _RangeHash, _Unused,
984 _RehashPolicy, _Traits>::
985 _M_insert_range(_InputIterator __first, _InputIterator __last,
986 const _NodeGetter& __node_gen, true_type __uks)
987 {
988 __hashtable& __h = _M_conjure_hashtable();
989 for (; __first != __last; ++__first)
990 __h._M_insert(*__first, __node_gen, __uks);
991 }
992
993 template<typename _Key, typename _Value, typename _Alloc,
994 typename _ExtractKey, typename _Equal,
995 typename _Hash, typename _RangeHash, typename _Unused,
996 typename _RehashPolicy, typename _Traits>
997 template<typename _InputIterator, typename _NodeGetter>
998 void
999 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1000 _Hash, _RangeHash, _Unused,
1001 _RehashPolicy, _Traits>::
1002 _M_insert_range(_InputIterator __first, _InputIterator __last,
1003 const _NodeGetter& __node_gen, false_type __uks)
1004 {
1005 using __rehash_type = typename __hashtable::__rehash_type;
1006 using __rehash_state = typename __hashtable::__rehash_state;
1007 using pair_type = std::pair<bool, std::size_t>;
1008
1009 size_type __n_elt = __detail::__distance_fw(__first, __last);
1010 if (__n_elt == 0)
1011 return;
1012
1013 __hashtable& __h = _M_conjure_hashtable();
1014 __rehash_type& __rehash = __h._M_rehash_policy;
1015 const __rehash_state& __saved_state = __rehash._M_state();
1016 pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
1017 __h._M_element_count,
1018 __n_elt);
1019
1020 if (__do_rehash.first)
1021 __h._M_rehash(__do_rehash.second, __saved_state);
1022
1023 for (; __first != __last; ++__first)
1024 __h._M_insert(*__first, __node_gen, __uks);
1025 }
1026
1027 /**
1028 * Primary class template _Insert.
1029 *
1030 * Defines @c insert member functions that depend on _Hashtable policies,
1031 * via partial specializations.
1032 */
1033 template<typename _Key, typename _Value, typename _Alloc,
1034 typename _ExtractKey, typename _Equal,
1035 typename _Hash, typename _RangeHash, typename _Unused,
1036 typename _RehashPolicy, typename _Traits,
1037 bool _Constant_iterators = _Traits::__constant_iterators::value>
1038 struct _Insert;
1039
1040 /// Specialization.
1041 template<typename _Key, typename _Value, typename _Alloc,
1042 typename _ExtractKey, typename _Equal,
1043 typename _Hash, typename _RangeHash, typename _Unused,
1044 typename _RehashPolicy, typename _Traits>
1045 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1046 _Hash, _RangeHash, _Unused,
1047 _RehashPolicy, _Traits, true>
1048 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1049 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1050 {
1051 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1052 _Equal, _Hash, _RangeHash, _Unused,
1053 _RehashPolicy, _Traits>;
1054
1055 using value_type = typename __base_type::value_type;
1056 using iterator = typename __base_type::iterator;
1057 using const_iterator = typename __base_type::const_iterator;
1058 using __ireturn_type = typename __base_type::__ireturn_type;
1059
1060 using __unique_keys = typename __base_type::__unique_keys;
1061 using __hashtable = typename __base_type::__hashtable;
1062 using __node_gen_type = typename __base_type::__node_gen_type;
1063
1064 using __base_type::insert;
1065
1066 __ireturn_type
1067 insert(value_type&& __v)
1068 {
1069 __hashtable& __h = this->_M_conjure_hashtable();
1070 __node_gen_type __node_gen(__h);
1071 return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
1072 }
1073
1074 iterator
1075 insert(const_iterator __hint, value_type&& __v)
1076 {
1077 __hashtable& __h = this->_M_conjure_hashtable();
1078 __node_gen_type __node_gen(__h);
1079 return __h._M_insert(__hint, std::move(__v), __node_gen,
1080 __unique_keys{});
1081 }
1082 };
1083
1084 /// Specialization.
1085 template<typename _Key, typename _Value, typename _Alloc,
1086 typename _ExtractKey, typename _Equal,
1087 typename _Hash, typename _RangeHash, typename _Unused,
1088 typename _RehashPolicy, typename _Traits>
1089 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1090 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1091 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1092 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1093 {
1094 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1095 _Equal, _Hash, _RangeHash, _Unused,
1096 _RehashPolicy, _Traits>;
1097 using value_type = typename __base_type::value_type;
1098 using iterator = typename __base_type::iterator;
1099 using const_iterator = typename __base_type::const_iterator;
1100
1101 using __unique_keys = typename __base_type::__unique_keys;
1102 using __hashtable = typename __base_type::__hashtable;
1103 using __ireturn_type = typename __base_type::__ireturn_type;
1104
1105 using __base_type::insert;
1106
1107 template<typename _Pair>
1108 using __is_cons = std::is_constructible<value_type, _Pair&&>;
1109
1110 template<typename _Pair>
1111 using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1112
1113 template<typename _Pair>
1114 using _IFconsp = typename _IFcons<_Pair>::type;
1115
1116 template<typename _Pair, typename = _IFconsp<_Pair>>
1117 __ireturn_type
1118 insert(_Pair&& __v)
1119 {
1120 __hashtable& __h = this->_M_conjure_hashtable();
1121 return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
1122 }
1123
1124 template<typename _Pair, typename = _IFconsp<_Pair>>
1125 iterator
1126 insert(const_iterator __hint, _Pair&& __v)
1127 {
1128 __hashtable& __h = this->_M_conjure_hashtable();
1129 return __h._M_emplace(__hint, __unique_keys{},
1130 std::forward<_Pair>(__v));
1131 }
1132 };
1133
1134 template<typename _Policy>
1135 using __has_load_factor = typename _Policy::__has_load_factor;
1136
1137 /**
1138 * Primary class template _Rehash_base.
1139 *
1140 * Give hashtable the max_load_factor functions and reserve iff the
1141 * rehash policy supports it.
1142 */
1143 template<typename _Key, typename _Value, typename _Alloc,
1144 typename _ExtractKey, typename _Equal,
1145 typename _Hash, typename _RangeHash, typename _Unused,
1146 typename _RehashPolicy, typename _Traits,
1147 typename =
1148 __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1149 struct _Rehash_base;
1150
1151 /// Specialization when rehash policy doesn't provide load factor management.
1152 template<typename _Key, typename _Value, typename _Alloc,
1153 typename _ExtractKey, typename _Equal,
1154 typename _Hash, typename _RangeHash, typename _Unused,
1155 typename _RehashPolicy, typename _Traits>
1156 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1157 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1158 false_type /* Has load factor */>
1159 {
1160 };
1161
1162 /// Specialization when rehash policy provide load factor management.
1163 template<typename _Key, typename _Value, typename _Alloc,
1164 typename _ExtractKey, typename _Equal,
1165 typename _Hash, typename _RangeHash, typename _Unused,
1166 typename _RehashPolicy, typename _Traits>
1167 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1168 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1169 true_type /* Has load factor */>
1170 {
1171 private:
1172 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1173 _Equal, _Hash, _RangeHash, _Unused,
1174 _RehashPolicy, _Traits>;
1175
1176 public:
1177 float
1178 max_load_factor() const noexcept
1179 {
1180 const __hashtable* __this = static_cast<const __hashtable*>(this);
1181 return __this->__rehash_policy().max_load_factor();
1182 }
1183
1184 void
1185 max_load_factor(float __z)
1186 {
1187 __hashtable* __this = static_cast<__hashtable*>(this);
1188 __this->__rehash_policy(_RehashPolicy(__z));
1189 }
1190
1191 void
1192 reserve(std::size_t __n)
1193 {
1194 __hashtable* __this = static_cast<__hashtable*>(this);
1195 __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1196 }
1197 };
1198
1199 /**
1200 * Primary class template _Hashtable_ebo_helper.
1201 *
1202 * Helper class using EBO when it is not forbidden (the type is not
1203 * final) and when it is worth it (the type is empty.)
1204 */
1205 template<int _Nm, typename _Tp,
1206 bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1207 struct _Hashtable_ebo_helper;
1208
1209 /// Specialization using EBO.
1210 template<int _Nm, typename _Tp>
1211 struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1212 : private _Tp
1213 {
1214 _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1215
1216 template<typename _OtherTp>
1217 _Hashtable_ebo_helper(_OtherTp&& __tp)
1218 : _Tp(std::forward<_OtherTp>(__tp))
1219 { }
1220
1221 const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1222 _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1223 };
1224
1225 /// Specialization not using EBO.
1226 template<int _Nm, typename _Tp>
1227 struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1228 {
1229 _Hashtable_ebo_helper() = default;
1230
1231 template<typename _OtherTp>
1232 _Hashtable_ebo_helper(_OtherTp&& __tp)
1233 : _M_tp(std::forward<_OtherTp>(__tp))
1234 { }
1235
1236 const _Tp& _M_cget() const { return _M_tp; }
1237 _Tp& _M_get() { return _M_tp; }
1238
1239 private:
1240 _Tp _M_tp{};
1241 };
1242
1243 /**
1244 * Primary class template _Local_iterator_base.
1245 *
1246 * Base class for local iterators, used to iterate within a bucket
1247 * but not between buckets.
1248 */
1249 template<typename _Key, typename _Value, typename _ExtractKey,
1250 typename _Hash, typename _RangeHash, typename _Unused,
1251 bool __cache_hash_code>
1252 struct _Local_iterator_base;
1253
1254 /**
1255 * Primary class template _Hash_code_base.
1256 *
1257 * Encapsulates two policy issues that aren't quite orthogonal.
1258 * (1) the difference between using a ranged hash function and using
1259 * the combination of a hash function and a range-hashing function.
1260 * In the former case we don't have such things as hash codes, so
1261 * we have a dummy type as placeholder.
1262 * (2) Whether or not we cache hash codes. Caching hash codes is
1263 * meaningless if we have a ranged hash function.
1264 *
1265 * We also put the key extraction objects here, for convenience.
1266 * Each specialization derives from one or more of the template
1267 * parameters to benefit from Ebo. This is important as this type
1268 * is inherited in some cases by the _Local_iterator_base type used
1269 * to implement local_iterator and const_local_iterator. As with
1270 * any iterator type we prefer to make it as small as possible.
1271 */
1272 template<typename _Key, typename _Value, typename _ExtractKey,
1273 typename _Hash, typename _RangeHash, typename _Unused,
1274 bool __cache_hash_code>
1275 struct _Hash_code_base
1276 : private _Hashtable_ebo_helper<1, _Hash>
1277 {
1278 private:
1279 using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1280
1281 // Gives the local iterator implementation access to _M_bucket_index().
1282 friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1283 _Hash, _RangeHash, _Unused, false>;
1284
1285 public:
1286 typedef _Hash hasher;
1287
1288 hasher
1289 hash_function() const
1290 { return _M_hash(); }
1291
1292 protected:
1293 typedef std::size_t __hash_code;
1294
1295 // We need the default constructor for the local iterators and _Hashtable
1296 // default constructor.
1297 _Hash_code_base() = default;
1298
1299 _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
1300
1301 __hash_code
1302 _M_hash_code(const _Key& __k) const
1303 {
1304 static_assert(__is_invocable<const _Hash&, const _Key&>{},
1305 "hash function must be invocable with an argument of key type");
1306 return _M_hash()(__k);
1307 }
1308
1309 template<typename _Kt>
1310 __hash_code
1311 _M_hash_code_tr(const _Kt& __k) const
1312 {
1313 static_assert(__is_invocable<const _Hash&, const _Kt&>{},
1314 "hash function must be invocable with an argument of key type");
1315 return _M_hash()(__k);
1316 }
1317
1318 __hash_code
1319 _M_hash_code(const _Hash&,
1320 const _Hash_node_value<_Value, true>& __n) const
1321 { return __n._M_hash_code; }
1322
1323 // Compute hash code using _Hash as __n _M_hash_code, if present, was
1324 // computed using _H2.
1325 template<typename _H2>
1326 __hash_code
1327 _M_hash_code(const _H2&,
1328 const _Hash_node_value<_Value, __cache_hash_code>& __n) const
1329 { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1330
1331 __hash_code
1332 _M_hash_code(const _Hash_node_value<_Value, false>& __n) const
1333 { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1334
1335 __hash_code
1336 _M_hash_code(const _Hash_node_value<_Value, true>& __n) const
1337 { return __n._M_hash_code; }
1338
1339 std::size_t
1340 _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
1341 { return _RangeHash{}(__c, __bkt_count); }
1342
1343 std::size_t
1344 _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
1345 std::size_t __bkt_count) const
1346 noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
1347 && noexcept(declval<const _RangeHash&>()((__hash_code)0,
1348 (std::size_t)0)) )
1349 {
1350 return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
1351 __bkt_count);
1352 }
1353
1354 std::size_t
1355 _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
1356 std::size_t __bkt_count) const
1357 noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
1358 (std::size_t)0)) )
1359 { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
1360
1361 void
1362 _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
1363 { }
1364
1365 void
1366 _M_copy_code(_Hash_node_code_cache<false>&,
1367 const _Hash_node_code_cache<false>&) const
1368 { }
1369
1370 void
1371 _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
1372 { __n._M_hash_code = __c; }
1373
1374 void
1375 _M_copy_code(_Hash_node_code_cache<true>& __to,
1376 const _Hash_node_code_cache<true>& __from) const
1377 { __to._M_hash_code = __from._M_hash_code; }
1378
1379 void
1380 _M_swap(_Hash_code_base& __x)
1381 { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
1382
1383 const _Hash&
1384 _M_hash() const { return __ebo_hash::_M_cget(); }
1385 };
1386
1387 /// Partial specialization used when nodes contain a cached hash code.
1388 template<typename _Key, typename _Value, typename _ExtractKey,
1389 typename _Hash, typename _RangeHash, typename _Unused>
1390 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1391 _Hash, _RangeHash, _Unused, true>
1392 : public _Node_iterator_base<_Value, true>
1393 {
1394 protected:
1395 using __base_node_iter = _Node_iterator_base<_Value, true>;
1396 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1397 _Hash, _RangeHash, _Unused, true>;
1398
1399 _Local_iterator_base() = default;
1400 _Local_iterator_base(const __hash_code_base&,
1401 _Hash_node<_Value, true>* __p,
1402 std::size_t __bkt, std::size_t __bkt_count)
1403 : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1404 { }
1405
1406 void
1407 _M_incr()
1408 {
1409 __base_node_iter::_M_incr();
1410 if (this->_M_cur)
1411 {
1412 std::size_t __bkt
1413 = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
1414 if (__bkt != _M_bucket)
1415 this->_M_cur = nullptr;
1416 }
1417 }
1418
1419 std::size_t _M_bucket;
1420 std::size_t _M_bucket_count;
1421
1422 public:
1423 std::size_t
1424 _M_get_bucket() const { return _M_bucket; } // for debug mode
1425 };
1426
1427 // Uninitialized storage for a _Hash_code_base.
1428 // This type is DefaultConstructible and Assignable even if the
1429 // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1430 // can be DefaultConstructible and Assignable.
1431 template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1432 struct _Hash_code_storage
1433 {
1434 __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1435
1436 _Tp*
1437 _M_h() { return _M_storage._M_ptr(); }
1438
1439 const _Tp*
1440 _M_h() const { return _M_storage._M_ptr(); }
1441 };
1442
1443 // Empty partial specialization for empty _Hash_code_base types.
1444 template<typename _Tp>
1445 struct _Hash_code_storage<_Tp, true>
1446 {
1447 static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1448
1449 // As _Tp is an empty type there will be no bytes written/read through
1450 // the cast pointer, so no strict-aliasing violation.
1451 _Tp*
1452 _M_h() { return reinterpret_cast<_Tp*>(this); }
1453
1454 const _Tp*
1455 _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1456 };
1457
1458 template<typename _Key, typename _Value, typename _ExtractKey,
1459 typename _Hash, typename _RangeHash, typename _Unused>
1460 using __hash_code_for_local_iter
1461 = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1462 _Hash, _RangeHash, _Unused, false>>;
1463
1464 // Partial specialization used when hash codes are not cached
1465 template<typename _Key, typename _Value, typename _ExtractKey,
1466 typename _Hash, typename _RangeHash, typename _Unused>
1467 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1468 _Hash, _RangeHash, _Unused, false>
1469 : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1470 _Unused>
1471 , _Node_iterator_base<_Value, false>
1472 {
1473 protected:
1474 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1475 _Hash, _RangeHash, _Unused, false>;
1476 using __node_iter_base = _Node_iterator_base<_Value, false>;
1477
1478 _Local_iterator_base() : _M_bucket_count(-1) { }
1479
1480 _Local_iterator_base(const __hash_code_base& __base,
1481 _Hash_node<_Value, false>* __p,
1482 std::size_t __bkt, std::size_t __bkt_count)
1483 : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1484 { _M_init(__base); }
1485
1486 ~_Local_iterator_base()
1487 {
1488 if (_M_bucket_count != size_t(-1))
1489 _M_destroy();
1490 }
1491
1492 _Local_iterator_base(const _Local_iterator_base& __iter)
1493 : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
1494 , _M_bucket_count(__iter._M_bucket_count)
1495 {
1496 if (_M_bucket_count != size_t(-1))
1497 _M_init(*__iter._M_h());
1498 }
1499
1500 _Local_iterator_base&
1501 operator=(const _Local_iterator_base& __iter)
1502 {
1503 if (_M_bucket_count != -1)
1504 _M_destroy();
1505 this->_M_cur = __iter._M_cur;
1506 _M_bucket = __iter._M_bucket;
1507 _M_bucket_count = __iter._M_bucket_count;
1508 if (_M_bucket_count != -1)
1509 _M_init(*__iter._M_h());
1510 return *this;
1511 }
1512
1513 void
1514 _M_incr()
1515 {
1516 __node_iter_base::_M_incr();
1517 if (this->_M_cur)
1518 {
1519 std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
1520 _M_bucket_count);
1521 if (__bkt != _M_bucket)
1522 this->_M_cur = nullptr;
1523 }
1524 }
1525
1526 std::size_t _M_bucket;
1527 std::size_t _M_bucket_count;
1528
1529 void
1530 _M_init(const __hash_code_base& __base)
1531 { ::new(this->_M_h()) __hash_code_base(__base); }
1532
1533 void
1534 _M_destroy() { this->_M_h()->~__hash_code_base(); }
1535
1536 public:
1537 std::size_t
1538 _M_get_bucket() const { return _M_bucket; } // for debug mode
1539 };
1540
1541 /// local iterators
1542 template<typename _Key, typename _Value, typename _ExtractKey,
1543 typename _Hash, typename _RangeHash, typename _Unused,
1544 bool __constant_iterators, bool __cache>
1545 struct _Local_iterator
1546 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1547 _Hash, _RangeHash, _Unused, __cache>
1548 {
1549 private:
1550 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1551 _Hash, _RangeHash, _Unused, __cache>;
1552 using __hash_code_base = typename __base_type::__hash_code_base;
1553
1554 public:
1555 using value_type = _Value;
1556 using pointer = __conditional_t<__constant_iterators,
1557 const value_type*, value_type*>;
1558 using reference = __conditional_t<__constant_iterators,
1559 const value_type&, value_type&>;
1560 using difference_type = ptrdiff_t;
1561 using iterator_category = forward_iterator_tag;
1562
1563 _Local_iterator() = default;
1564
1565 _Local_iterator(const __hash_code_base& __base,
1566 _Hash_node<_Value, __cache>* __n,
1567 std::size_t __bkt, std::size_t __bkt_count)
1568 : __base_type(__base, __n, __bkt, __bkt_count)
1569 { }
1570
1571 reference
1572 operator*() const
1573 { return this->_M_cur->_M_v(); }
1574
1575 pointer
1576 operator->() const
1577 { return this->_M_cur->_M_valptr(); }
1578
1579 _Local_iterator&
1580 operator++()
1581 {
1582 this->_M_incr();
1583 return *this;
1584 }
1585
1586 _Local_iterator
1587 operator++(int)
1588 {
1589 _Local_iterator __tmp(*this);
1590 this->_M_incr();
1591 return __tmp;
1592 }
1593 };
1594
1595 /// local const_iterators
1596 template<typename _Key, typename _Value, typename _ExtractKey,
1597 typename _Hash, typename _RangeHash, typename _Unused,
1598 bool __constant_iterators, bool __cache>
1599 struct _Local_const_iterator
1600 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1601 _Hash, _RangeHash, _Unused, __cache>
1602 {
1603 private:
1604 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1605 _Hash, _RangeHash, _Unused, __cache>;
1606 using __hash_code_base = typename __base_type::__hash_code_base;
1607
1608 public:
1609 typedef _Value value_type;
1610 typedef const value_type* pointer;
1611 typedef const value_type& reference;
1612 typedef std::ptrdiff_t difference_type;
1613 typedef std::forward_iterator_tag iterator_category;
1614
1615 _Local_const_iterator() = default;
1616
1617 _Local_const_iterator(const __hash_code_base& __base,
1618 _Hash_node<_Value, __cache>* __n,
1619 std::size_t __bkt, std::size_t __bkt_count)
1620 : __base_type(__base, __n, __bkt, __bkt_count)
1621 { }
1622
1623 _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1624 _Hash, _RangeHash, _Unused,
1625 __constant_iterators,
1626 __cache>& __x)
1627 : __base_type(__x)
1628 { }
1629
1630 reference
1631 operator*() const
1632 { return this->_M_cur->_M_v(); }
1633
1634 pointer
1635 operator->() const
1636 { return this->_M_cur->_M_valptr(); }
1637
1638 _Local_const_iterator&
1639 operator++()
1640 {
1641 this->_M_incr();
1642 return *this;
1643 }
1644
1645 _Local_const_iterator
1646 operator++(int)
1647 {
1648 _Local_const_iterator __tmp(*this);
1649 this->_M_incr();
1650 return __tmp;
1651 }
1652 };
1653
1654 /**
1655 * Primary class template _Hashtable_base.
1656 *
1657 * Helper class adding management of _Equal functor to
1658 * _Hash_code_base type.
1659 *
1660 * Base class templates are:
1661 * - __detail::_Hash_code_base
1662 * - __detail::_Hashtable_ebo_helper
1663 */
1664 template<typename _Key, typename _Value, typename _ExtractKey,
1665 typename _Equal, typename _Hash, typename _RangeHash,
1666 typename _Unused, typename _Traits>
1667 struct _Hashtable_base
1668 : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1669 _Unused, _Traits::__hash_cached::value>,
1670 private _Hashtable_ebo_helper<0, _Equal>
1671 {
1672 public:
1673 typedef _Key key_type;
1674 typedef _Value value_type;
1675 typedef _Equal key_equal;
1676 typedef std::size_t size_type;
1677 typedef std::ptrdiff_t difference_type;
1678
1679 using __traits_type = _Traits;
1680 using __hash_cached = typename __traits_type::__hash_cached;
1681
1682 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1683 _Hash, _RangeHash, _Unused,
1684 __hash_cached::value>;
1685
1686 using __hash_code = typename __hash_code_base::__hash_code;
1687
1688 private:
1689 using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1690
1691 static bool
1692 _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
1693 { return true; }
1694
1695 static bool
1696 _S_node_equals(const _Hash_node_code_cache<false>&,
1697 const _Hash_node_code_cache<false>&)
1698 { return true; }
1699
1700 static bool
1701 _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
1702 { return __c == __n._M_hash_code; }
1703
1704 static bool
1705 _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
1706 const _Hash_node_code_cache<true>& __rhn)
1707 { return __lhn._M_hash_code == __rhn._M_hash_code; }
1708
1709 protected:
1710 _Hashtable_base() = default;
1711
1712 _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
1713 : __hash_code_base(__hash), _EqualEBO(__eq)
1714 { }
1715
1716 bool
1717 _M_key_equals(const _Key& __k,
1718 const _Hash_node_value<_Value,
1719 __hash_cached::value>& __n) const
1720 {
1721 static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1722 "key equality predicate must be invocable with two arguments of "
1723 "key type");
1724 return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1725 }
1726
1727 template<typename _Kt>
1728 bool
1729 _M_key_equals_tr(const _Kt& __k,
1730 const _Hash_node_value<_Value,
1731 __hash_cached::value>& __n) const
1732 {
1733 static_assert(
1734 __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
1735 "key equality predicate must be invocable with two arguments of "
1736 "key type");
1737 return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1738 }
1739
1740 bool
1741 _M_equals(const _Key& __k, __hash_code __c,
1742 const _Hash_node_value<_Value, __hash_cached::value>& __n) const
1743 { return _S_equals(__c, __n) && _M_key_equals(__k, __n); }
1744
1745 template<typename _Kt>
1746 bool
1747 _M_equals_tr(const _Kt& __k, __hash_code __c,
1748 const _Hash_node_value<_Value,
1749 __hash_cached::value>& __n) const
1750 { return _S_equals(__c, __n) && _M_key_equals_tr(__k, __n); }
1751
1752 bool
1753 _M_node_equals(
1754 const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
1755 const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
1756 {
1757 return _S_node_equals(__lhn, __rhn)
1758 && _M_key_equals(_ExtractKey{}(__lhn._M_v()), __rhn);
1759 }
1760
1761 void
1762 _M_swap(_Hashtable_base& __x)
1763 {
1764 __hash_code_base::_M_swap(__x);
1765 std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1766 }
1767
1768 const _Equal&
1769 _M_eq() const { return _EqualEBO::_M_cget(); }
1770 };
1771
1772 /**
1773 * Primary class template _Equality.
1774 *
1775 * This is for implementing equality comparison for unordered
1776 * containers, per N3068, by John Lakos and Pablo Halpern.
1777 * Algorithmically, we follow closely the reference implementations
1778 * therein.
1779 */
1780 template<typename _Key, typename _Value, typename _Alloc,
1781 typename _ExtractKey, typename _Equal,
1782 typename _Hash, typename _RangeHash, typename _Unused,
1783 typename _RehashPolicy, typename _Traits,
1784 bool _Unique_keys = _Traits::__unique_keys::value>
1785 struct _Equality;
1786
1787 /// unordered_map and unordered_set specializations.
1788 template<typename _Key, typename _Value, typename _Alloc,
1789 typename _ExtractKey, typename _Equal,
1790 typename _Hash, typename _RangeHash, typename _Unused,
1791 typename _RehashPolicy, typename _Traits>
1792 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1793 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
1794 {
1795 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1796 _Hash, _RangeHash, _Unused,
1797 _RehashPolicy, _Traits>;
1798
1799 bool
1800 _M_equal(const __hashtable&) const;
1801 };
1802
1803 template<typename _Key, typename _Value, typename _Alloc,
1804 typename _ExtractKey, typename _Equal,
1805 typename _Hash, typename _RangeHash, typename _Unused,
1806 typename _RehashPolicy, typename _Traits>
1807 bool
1808 _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1809 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
1810 _M_equal(const __hashtable& __other) const
1811 {
1812 using __node_type = typename __hashtable::__node_type;
1813 const __hashtable* __this = static_cast<const __hashtable*>(this);
1814 if (__this->size() != __other.size())
1815 return false;
1816
1817 for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1818 {
1819 std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1820 auto __prev_n = __other._M_buckets[__ybkt];
1821 if (!__prev_n)
1822 return false;
1823
1824 for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1825 __n = __n->_M_next())
1826 {
1827 if (__n->_M_v() == *__itx)
1828 break;
1829
1830 if (!__n->_M_nxt
1831 || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
1832 return false;
1833 }
1834 }
1835
1836 return true;
1837 }
1838
1839 /// unordered_multiset and unordered_multimap specializations.
1840 template<typename _Key, typename _Value, typename _Alloc,
1841 typename _ExtractKey, typename _Equal,
1842 typename _Hash, typename _RangeHash, typename _Unused,
1843 typename _RehashPolicy, typename _Traits>
1844 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1845 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1846 {
1847 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1848 _Hash, _RangeHash, _Unused,
1849 _RehashPolicy, _Traits>;
1850
1851 bool
1852 _M_equal(const __hashtable&) const;
1853 };
1854
1855 template<typename _Key, typename _Value, typename _Alloc,
1856 typename _ExtractKey, typename _Equal,
1857 typename _Hash, typename _RangeHash, typename _Unused,
1858 typename _RehashPolicy, typename _Traits>
1859 bool
1860 _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1861 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
1862 _M_equal(const __hashtable& __other) const
1863 {
1864 using __node_type = typename __hashtable::__node_type;
1865 const __hashtable* __this = static_cast<const __hashtable*>(this);
1866 if (__this->size() != __other.size())
1867 return false;
1868
1869 for (auto __itx = __this->begin(); __itx != __this->end();)
1870 {
1871 std::size_t __x_count = 1;
1872 auto __itx_end = __itx;
1873 for (++__itx_end; __itx_end != __this->end()
1874 && __this->key_eq()(_ExtractKey{}(*__itx),
1875 _ExtractKey{}(*__itx_end));
1876 ++__itx_end)
1877 ++__x_count;
1878
1879 std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1880 auto __y_prev_n = __other._M_buckets[__ybkt];
1881 if (!__y_prev_n)
1882 return false;
1883
1884 __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1885 for (;;)
1886 {
1887 if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
1888 _ExtractKey{}(*__itx)))
1889 break;
1890
1891 auto __y_ref_n = __y_n;
1892 for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
1893 if (!__other._M_node_equals(*__y_ref_n, *__y_n))
1894 break;
1895
1896 if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
1897 return false;
1898 }
1899
1900 typename __hashtable::const_iterator __ity(__y_n);
1901 for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1902 if (--__x_count == 0)
1903 break;
1904
1905 if (__x_count != 0)
1906 return false;
1907
1908 if (!std::is_permutation(__itx, __itx_end, __ity))
1909 return false;
1910
1911 __itx = __itx_end;
1912 }
1913 return true;
1914 }
1915
1916 /**
1917 * This type deals with all allocation and keeps an allocator instance
1918 * through inheritance to benefit from EBO when possible.
1919 */
1920 template<typename _NodeAlloc>
1921 struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1922 {
1923 private:
1924 using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1925
1926 template<typename>
1927 struct __get_value_type;
1928 template<typename _Val, bool _Cache_hash_code>
1929 struct __get_value_type<_Hash_node<_Val, _Cache_hash_code>>
1930 { using type = _Val; };
1931
1932 public:
1933 using __node_type = typename _NodeAlloc::value_type;
1934 using __node_alloc_type = _NodeAlloc;
1935 // Use __gnu_cxx to benefit from _S_always_equal and al.
1936 using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1937
1938 using __value_alloc_traits = typename __node_alloc_traits::template
1939 rebind_traits<typename __get_value_type<__node_type>::type>;
1940
1941 using __node_ptr = __node_type*;
1942 using __node_base = _Hash_node_base;
1943 using __node_base_ptr = __node_base*;
1944 using __buckets_alloc_type =
1945 __alloc_rebind<__node_alloc_type, __node_base_ptr>;
1946 using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
1947 using __buckets_ptr = __node_base_ptr*;
1948
1949 _Hashtable_alloc() = default;
1950 _Hashtable_alloc(const _Hashtable_alloc&) = default;
1951 _Hashtable_alloc(_Hashtable_alloc&&) = default;
1952
1953 template<typename _Alloc>
1954 _Hashtable_alloc(_Alloc&& __a)
1955 : __ebo_node_alloc(std::forward<_Alloc>(__a))
1956 { }
1957
1958 __node_alloc_type&
1959 _M_node_allocator()
1960 { return __ebo_node_alloc::_M_get(); }
1961
1962 const __node_alloc_type&
1963 _M_node_allocator() const
1964 { return __ebo_node_alloc::_M_cget(); }
1965
1966 // Allocate a node and construct an element within it.
1967 template<typename... _Args>
1968 __node_ptr
1969 _M_allocate_node(_Args&&... __args);
1970
1971 // Destroy the element within a node and deallocate the node.
1972 void
1973 _M_deallocate_node(__node_ptr __n);
1974
1975 // Deallocate a node.
1976 void
1977 _M_deallocate_node_ptr(__node_ptr __n);
1978
1979 // Deallocate the linked list of nodes pointed to by __n.
1980 // The elements within the nodes are destroyed.
1981 void
1982 _M_deallocate_nodes(__node_ptr __n);
1983
1984 __buckets_ptr
1985 _M_allocate_buckets(std::size_t __bkt_count);
1986
1987 void
1988 _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
1989 };
1990
1991 // Definitions of class template _Hashtable_alloc's out-of-line member
1992 // functions.
1993 template<typename _NodeAlloc>
1994 template<typename... _Args>
1995 auto
1996 _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1997 -> __node_ptr
1998 {
1999 auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
2000 __node_ptr __n = std::__to_address(__nptr);
2001 __try
2002 {
2003 ::new ((void*)__n) __node_type;
2004 __node_alloc_traits::construct(_M_node_allocator(),
2005 __n->_M_valptr(),
2006 std::forward<_Args>(__args)...);
2007 return __n;
2008 }
2009 __catch(...)
2010 {
2011 __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
2012 __throw_exception_again;
2013 }
2014 }
2015
2016 template<typename _NodeAlloc>
2017 void
2018 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
2019 {
2020 __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
2021 _M_deallocate_node_ptr(__n);
2022 }
2023
2024 template<typename _NodeAlloc>
2025 void
2026 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
2027 {
2028 typedef typename __node_alloc_traits::pointer _Ptr;
2029 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
2030 __n->~__node_type();
2031 __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
2032 }
2033
2034 template<typename _NodeAlloc>
2035 void
2036 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
2037 {
2038 while (__n)
2039 {
2040 __node_ptr __tmp = __n;
2041 __n = __n->_M_next();
2042 _M_deallocate_node(__tmp);
2043 }
2044 }
2045
2046 template<typename _NodeAlloc>
2047 auto
2048 _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
2049 -> __buckets_ptr
2050 {
2051 __buckets_alloc_type __alloc(_M_node_allocator());
2052
2053 auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
2054 __buckets_ptr __p = std::__to_address(__ptr);
2055 __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
2056 return __p;
2057 }
2058
2059 template<typename _NodeAlloc>
2060 void
2061 _Hashtable_alloc<_NodeAlloc>::
2062 _M_deallocate_buckets(__buckets_ptr __bkts,
2063 std::size_t __bkt_count)
2064 {
2065 typedef typename __buckets_alloc_traits::pointer _Ptr;
2066 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
2067 __buckets_alloc_type __alloc(_M_node_allocator());
2068 __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
2069 }
2070
2071 ///@} hashtable-detail
2072 } // namespace __detail
2073 /// @endcond
2074 _GLIBCXX_END_NAMESPACE_VERSION
2075 } // namespace std
2076
2077 #endif // _HASHTABLE_POLICY_H