libstdc++
bits/hashtable.h
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1// hashtable.h header -*- C++ -*-
2
3// Copyright (C) 2007-2024 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.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{unordered_map, unordered_set}
28 */
29
30#ifndef _HASHTABLE_H
31#define _HASHTABLE_H 1
32
33#ifdef _GLIBCXX_SYSHDR
34#pragma GCC system_header
35#endif
36
39#include <bits/stl_algobase.h> // fill_n, is_permutation
40#include <bits/stl_function.h> // __has_is_transparent_t
41#if __cplusplus > 201402L
42# include <bits/node_handle.h>
43#endif
44
45#pragma GCC diagnostic push
46#pragma GCC diagnostic ignored "-Wc++11-extensions"
47
48namespace std _GLIBCXX_VISIBILITY(default)
49{
50_GLIBCXX_BEGIN_NAMESPACE_VERSION
51/// @cond undocumented
52
53 template<typename _Tp, typename _Hash>
54 using __cache_default
55 = __not_<__and_<// Do not cache for fast hasher.
56 __is_fast_hash<_Hash>,
57 // Mandatory for the rehash process.
58 __is_nothrow_invocable<const _Hash&, const _Tp&>>>;
59
60 // Helper to conditionally delete the default constructor.
61 // The _Hash_node_base type is used to distinguish this specialization
62 // from any other potentially-overlapping subobjects of the hashtable.
63 template<typename _Equal, typename _Hash, typename _Allocator>
64 using _Hashtable_enable_default_ctor
65 = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
66 is_default_constructible<_Hash>,
67 is_default_constructible<_Allocator>>{},
68 __detail::_Hash_node_base>;
69
70 /**
71 * Primary class template _Hashtable.
72 *
73 * @ingroup hashtable-detail
74 *
75 * @tparam _Value CopyConstructible type.
76 *
77 * @tparam _Key CopyConstructible type.
78 *
79 * @tparam _Alloc An allocator type
80 * ([lib.allocator.requirements]) whose _Alloc::value_type is
81 * _Value. As a conforming extension, we allow for
82 * _Alloc::value_type != _Value.
83 *
84 * @tparam _ExtractKey Function object that takes an object of type
85 * _Value and returns a value of type _Key.
86 *
87 * @tparam _Equal Function object that takes two objects of type k
88 * and returns a bool-like value that is true if the two objects
89 * are considered equal.
90 *
91 * @tparam _Hash The hash function. A unary function object with
92 * argument type _Key and result type size_t. Return values should
93 * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
94 *
95 * @tparam _RangeHash The range-hashing function (in the terminology of
96 * Tavori and Dreizin). A binary function object whose argument
97 * types and result type are all size_t. Given arguments r and N,
98 * the return value is in the range [0, N).
99 *
100 * @tparam _Unused Not used.
101 *
102 * @tparam _RehashPolicy Policy class with three members, all of
103 * which govern the bucket count. _M_next_bkt(n) returns a bucket
104 * count no smaller than n. _M_bkt_for_elements(n) returns a
105 * bucket count appropriate for an element count of n.
106 * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
107 * current bucket count is n_bkt and the current element count is
108 * n_elt, we need to increase the bucket count for n_ins insertions.
109 * If so, returns make_pair(true, n), where n is the new bucket count. If
110 * not, returns make_pair(false, <anything>)
111 *
112 * @tparam _Traits Compile-time class with three boolean
113 * std::integral_constant members: __cache_hash_code, __constant_iterators,
114 * __unique_keys.
115 *
116 * Each _Hashtable data structure has:
117 *
118 * - _Bucket[] _M_buckets
119 * - _Hash_node_base _M_before_begin
120 * - size_type _M_bucket_count
121 * - size_type _M_element_count
122 *
123 * with _Bucket being _Hash_node_base* and _Hash_node containing:
124 *
125 * - _Hash_node* _M_next
126 * - Tp _M_value
127 * - size_t _M_hash_code if cache_hash_code is true
128 *
129 * In terms of Standard containers the hashtable is like the aggregation of:
130 *
131 * - std::forward_list<_Node> containing the elements
132 * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
133 *
134 * The non-empty buckets contain the node before the first node in the
135 * bucket. This design makes it possible to implement something like a
136 * std::forward_list::insert_after on container insertion and
137 * std::forward_list::erase_after on container erase
138 * calls. _M_before_begin is equivalent to
139 * std::forward_list::before_begin. Empty buckets contain
140 * nullptr. Note that one of the non-empty buckets contains
141 * &_M_before_begin which is not a dereferenceable node so the
142 * node pointer in a bucket shall never be dereferenced, only its
143 * next node can be.
144 *
145 * Walking through a bucket's nodes requires a check on the hash code to
146 * see if each node is still in the bucket. Such a design assumes a
147 * quite efficient hash functor and is one of the reasons it is
148 * highly advisable to set __cache_hash_code to true.
149 *
150 * The container iterators are simply built from nodes. This way
151 * incrementing the iterator is perfectly efficient independent of
152 * how many empty buckets there are in the container.
153 *
154 * On insert we compute the element's hash code and use it to find the
155 * bucket index. If the element must be inserted in an empty bucket
156 * we add it at the beginning of the singly linked list and make the
157 * bucket point to _M_before_begin. The bucket that used to point to
158 * _M_before_begin, if any, is updated to point to its new before
159 * begin node.
160 *
161 * Note that all equivalent values, if any, are next to each other, if
162 * we find a non-equivalent value after an equivalent one it means that
163 * we won't find any new equivalent value.
164 *
165 * On erase, the simple iterator design requires using the hash
166 * functor to get the index of the bucket to update. For this
167 * reason, when __cache_hash_code is set to false the hash functor must
168 * not throw and this is enforced by a static assertion.
169 *
170 * Functionality is implemented by decomposition into base classes,
171 * where the derived _Hashtable class is used in _Map_base and
172 * _Rehash_base base classes to access the
173 * "this" pointer. _Hashtable_base is used in the base classes as a
174 * non-recursive, fully-completed-type so that detailed nested type
175 * information, such as iterator type and node type, can be
176 * used. This is similar to the "Curiously Recurring Template
177 * Pattern" (CRTP) technique, but uses a reconstructed, not
178 * explicitly passed, template pattern.
179 *
180 * Base class templates are:
181 * - __detail::_Hashtable_base
182 * - __detail::_Map_base
183 * - __detail::_Rehash_base
184 */
185 template<typename _Key, typename _Value, typename _Alloc,
186 typename _ExtractKey, typename _Equal,
187 typename _Hash, typename _RangeHash, typename _Unused,
188 typename _RehashPolicy, typename _Traits>
189 class _Hashtable
190 : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
191 _Hash, _RangeHash, _Unused, _Traits>,
192 public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
193 _Hash, _RangeHash, _Unused,
194 _RehashPolicy, _Traits>,
195 public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
196 _Hash, _RangeHash, _Unused,
197 _RehashPolicy, _Traits>,
198 private __detail::_Hashtable_alloc<
199 __alloc_rebind<_Alloc,
200 __detail::_Hash_node<_Value,
201 _Traits::__hash_cached::value>>>,
202 private _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>
203 {
204 static_assert(is_same<typename remove_cv<_Value>::type, _Value>::value,
205 "unordered container must have a non-const, non-volatile value_type");
206#if __cplusplus > 201703L || defined __STRICT_ANSI__
207 static_assert(is_same<typename _Alloc::value_type, _Value>{},
208 "unordered container must have the same value_type as its allocator");
209#endif
210 static_assert(is_copy_constructible<_Hash>::value,
211 "hash function must be copy constructible");
212
213 using __traits_type = _Traits;
214 using __hash_cached = typename __traits_type::__hash_cached;
215 using __constant_iterators = typename __traits_type::__constant_iterators;
216 using __node_type = __detail::_Hash_node<_Value, __hash_cached::value>;
217 using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
218
219 using __hashtable_alloc = __detail::_Hashtable_alloc<__node_alloc_type>;
220
221 using __node_value_type =
222 __detail::_Hash_node_value<_Value, __hash_cached::value>;
223 using __node_ptr = typename __hashtable_alloc::__node_ptr;
224 using __value_alloc_traits =
225 typename __hashtable_alloc::__value_alloc_traits;
226 using __node_alloc_traits =
227 typename __hashtable_alloc::__node_alloc_traits;
228 using __node_base = typename __hashtable_alloc::__node_base;
229 using __node_base_ptr = typename __hashtable_alloc::__node_base_ptr;
230 using __buckets_ptr = typename __hashtable_alloc::__buckets_ptr;
231
232 using __enable_default_ctor
233 = _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>;
234 using __rehash_guard_t
235 = __detail::_RehashStateGuard<_RehashPolicy>;
236
237 public:
238 typedef _Key key_type;
239 typedef _Value value_type;
240 typedef _Alloc allocator_type;
241 typedef _Equal key_equal;
242
243 // mapped_type, if present, comes from _Map_base.
244 // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
245 typedef typename __value_alloc_traits::pointer pointer;
246 typedef typename __value_alloc_traits::const_pointer const_pointer;
247 typedef value_type& reference;
248 typedef const value_type& const_reference;
249
250 using iterator
251 = __detail::_Node_iterator<_Value, __constant_iterators::value,
252 __hash_cached::value>;
253
254 using const_iterator
255 = __detail::_Node_const_iterator<_Value, __constant_iterators::value,
256 __hash_cached::value>;
257
258 using local_iterator = __detail::_Local_iterator<key_type, _Value,
259 _ExtractKey, _Hash, _RangeHash, _Unused,
260 __constant_iterators::value,
261 __hash_cached::value>;
262
263 using const_local_iterator = __detail::_Local_const_iterator<
264 key_type, _Value,
265 _ExtractKey, _Hash, _RangeHash, _Unused,
266 __constant_iterators::value, __hash_cached::value>;
267
268 private:
269 using __rehash_type = _RehashPolicy;
270
271 using __unique_keys = typename __traits_type::__unique_keys;
272
273 using __hashtable_base = __detail::
274 _Hashtable_base<_Key, _Value, _ExtractKey,
275 _Equal, _Hash, _RangeHash, _Unused, _Traits>;
276
277 using __hash_code_base = typename __hashtable_base::__hash_code_base;
278 using __hash_code = typename __hashtable_base::__hash_code;
279 using __ireturn_type = __conditional_t<__unique_keys::value,
281 iterator>;
282
283 using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
284 _Equal, _Hash, _RangeHash, _Unused,
285 _RehashPolicy, _Traits>;
286
287 using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
288 _ExtractKey, _Equal,
289 _Hash, _RangeHash, _Unused,
290 _RehashPolicy, _Traits>;
291
292 using __node_builder_t = __detail::_NodeBuilder<_ExtractKey>;
293
294 // Simple RAII type for managing a node containing an element
295 struct _Scoped_node
296 {
297 // Take ownership of a node with a constructed element.
298 _Scoped_node(__node_ptr __n, __hashtable_alloc* __h)
299 : _M_h(__h), _M_node(__n) { }
300
301 // Allocate a node and construct an element within it.
302 template<typename... _Args>
303 _Scoped_node(__hashtable_alloc* __h, _Args&&... __args)
304 : _M_h(__h),
305 _M_node(__h->_M_allocate_node(std::forward<_Args>(__args)...))
306 { }
307
308 // Destroy element and deallocate node.
309 ~_Scoped_node() { if (_M_node) _M_h->_M_deallocate_node(_M_node); };
310
311 _Scoped_node(const _Scoped_node&) = delete;
312 _Scoped_node& operator=(const _Scoped_node&) = delete;
313
314 __hashtable_alloc* _M_h;
315 __node_ptr _M_node;
316 };
317
318 // Compile-time diagnostics.
319
320 // _Hash_code_base has everything protected, so use this derived type to
321 // access it.
322 struct __hash_code_base_access : __hash_code_base
323 { using __hash_code_base::_M_bucket_index; };
324
325 // To get bucket index we need _RangeHash to be non-throwing.
326 static_assert(is_nothrow_default_constructible<_RangeHash>::value,
327 "Functor used to map hash code to bucket index"
328 " must be nothrow default constructible");
329 static_assert(noexcept(
330 std::declval<const _RangeHash&>()((std::size_t)0, (std::size_t)0)),
331 "Functor used to map hash code to bucket index must be"
332 " noexcept");
333
334 // To compute bucket index we also need _ExtractKey to be non-throwing.
335 static_assert(is_nothrow_default_constructible<_ExtractKey>::value,
336 "_ExtractKey must be nothrow default constructible");
337 static_assert(noexcept(
338 std::declval<const _ExtractKey&>()(std::declval<_Value>())),
339 "_ExtractKey functor must be noexcept invocable");
340
341 template<typename _Keya, typename _Valuea, typename _Alloca,
342 typename _ExtractKeya, typename _Equala,
343 typename _Hasha, typename _RangeHasha, typename _Unuseda,
344 typename _RehashPolicya, typename _Traitsa,
345 bool _Unique_keysa>
346 friend struct __detail::_Map_base;
347
348 public:
349 using size_type = typename __hashtable_base::size_type;
350 using difference_type = typename __hashtable_base::difference_type;
351
352#if __cplusplus > 201402L
353 using node_type = _Node_handle<_Key, _Value, __node_alloc_type>;
354 using insert_return_type = _Node_insert_return<iterator, node_type>;
355#endif
356
357 private:
358 __buckets_ptr _M_buckets = &_M_single_bucket;
359 size_type _M_bucket_count = 1;
360 __node_base _M_before_begin;
361 size_type _M_element_count = 0;
362 _RehashPolicy _M_rehash_policy;
363
364 // A single bucket used when only need for 1 bucket. Especially
365 // interesting in move semantic to leave hashtable with only 1 bucket
366 // which is not allocated so that we can have those operations noexcept
367 // qualified.
368 // Note that we can't leave hashtable with 0 bucket without adding
369 // numerous checks in the code to avoid 0 modulus.
370 __node_base_ptr _M_single_bucket = nullptr;
371
372 void
373 _M_update_bbegin()
374 {
375 if (auto __begin = _M_begin())
376 _M_buckets[_M_bucket_index(*__begin)] = &_M_before_begin;
377 }
378
379 void
380 _M_update_bbegin(__node_ptr __n)
381 {
382 _M_before_begin._M_nxt = __n;
383 _M_update_bbegin();
384 }
385
386 bool
387 _M_uses_single_bucket(__buckets_ptr __bkts) const
388 { return __builtin_expect(__bkts == &_M_single_bucket, false); }
389
390 bool
391 _M_uses_single_bucket() const
392 { return _M_uses_single_bucket(_M_buckets); }
393
394 static constexpr size_t
395 __small_size_threshold() noexcept
396 {
397 return
398 __detail::_Hashtable_hash_traits<_Hash>::__small_size_threshold();
399 }
400
401 __hashtable_alloc&
402 _M_base_alloc() { return *this; }
403
404 __buckets_ptr
405 _M_allocate_buckets(size_type __bkt_count)
406 {
407 if (__builtin_expect(__bkt_count == 1, false))
408 {
409 _M_single_bucket = nullptr;
410 return &_M_single_bucket;
411 }
412
413 return __hashtable_alloc::_M_allocate_buckets(__bkt_count);
414 }
415
416 void
417 _M_deallocate_buckets(__buckets_ptr __bkts, size_type __bkt_count)
418 {
419 if (_M_uses_single_bucket(__bkts))
420 return;
421
422 __hashtable_alloc::_M_deallocate_buckets(__bkts, __bkt_count);
423 }
424
425 void
426 _M_deallocate_buckets()
427 { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
428
429 // Gets bucket begin, deals with the fact that non-empty buckets contain
430 // their before begin node.
431 __node_ptr
432 _M_bucket_begin(size_type __bkt) const
433 {
434 __node_base_ptr __n = _M_buckets[__bkt];
435 return __n ? static_cast<__node_ptr>(__n->_M_nxt) : nullptr;
436 }
437
438 __node_ptr
439 _M_begin() const
440 { return static_cast<__node_ptr>(_M_before_begin._M_nxt); }
441
442 // Assign *this using another _Hashtable instance. Whether elements
443 // are copied or moved depends on the _Ht reference.
444 template<typename _Ht>
445 void
446 _M_assign_elements(_Ht&&);
447
448 template<typename _Ht>
449 void
450 _M_assign(_Ht&& __ht)
451 {
452 __detail::_AllocNode<__node_alloc_type> __alloc_node_gen(*this);
453 _M_assign(std::forward<_Ht>(__ht), __alloc_node_gen);
454 }
455
456 template<typename _Ht, typename _NodeGenerator>
457 void
458 _M_assign(_Ht&&, _NodeGenerator&);
459
460 void
461 _M_move_assign(_Hashtable&&, true_type);
462
463 void
464 _M_move_assign(_Hashtable&&, false_type);
465
466 void
467 _M_reset() noexcept;
468
469 _Hashtable(const _Hash& __h, const _Equal& __eq,
470 const allocator_type& __a)
471 : __hashtable_base(__h, __eq),
472 __hashtable_alloc(__node_alloc_type(__a)),
473 __enable_default_ctor(_Enable_default_constructor_tag{})
474 { }
475
476 template<bool _No_realloc = true>
477 static constexpr bool
478 _S_nothrow_move()
479 {
480#if __cplusplus <= 201402L
481 return __and_<__bool_constant<_No_realloc>,
482 is_nothrow_copy_constructible<_Hash>,
483 is_nothrow_copy_constructible<_Equal>>::value;
484#else
485 if constexpr (_No_realloc)
486 if constexpr (is_nothrow_copy_constructible<_Hash>())
487 return is_nothrow_copy_constructible<_Equal>();
488 return false;
489#endif
490 }
491
492 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
493 true_type /* alloc always equal */)
494 noexcept(_S_nothrow_move());
495
496 _Hashtable(_Hashtable&&, __node_alloc_type&&,
497 false_type /* alloc always equal */);
498
499 template<typename _InputIterator>
500 _Hashtable(_InputIterator __first, _InputIterator __last,
501 size_type __bkt_count_hint,
502 const _Hash&, const _Equal&, const allocator_type&,
503 true_type __uks);
504
505 template<typename _InputIterator>
506 _Hashtable(_InputIterator __first, _InputIterator __last,
507 size_type __bkt_count_hint,
508 const _Hash&, const _Equal&, const allocator_type&,
509 false_type __uks);
510
511 public:
512 // Constructor, destructor, assignment, swap
513 _Hashtable() = default;
514
515 _Hashtable(const _Hashtable&);
516
517 _Hashtable(const _Hashtable&, const allocator_type&);
518
519 explicit
520 _Hashtable(size_type __bkt_count_hint,
521 const _Hash& __hf = _Hash(),
522 const key_equal& __eql = key_equal(),
523 const allocator_type& __a = allocator_type());
524
525 // Use delegating constructors.
526 _Hashtable(_Hashtable&& __ht)
527 noexcept(_S_nothrow_move())
528 : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
529 true_type{})
530 { }
531
532 _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
533 noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
534 : _Hashtable(std::move(__ht), __node_alloc_type(__a),
535 typename __node_alloc_traits::is_always_equal{})
536 { }
537
538 explicit
539 _Hashtable(const allocator_type& __a)
540 : __hashtable_alloc(__node_alloc_type(__a)),
541 __enable_default_ctor(_Enable_default_constructor_tag{})
542 { }
543
544 template<typename _InputIterator>
545 _Hashtable(_InputIterator __f, _InputIterator __l,
546 size_type __bkt_count_hint = 0,
547 const _Hash& __hf = _Hash(),
548 const key_equal& __eql = key_equal(),
549 const allocator_type& __a = allocator_type())
550 : _Hashtable(__f, __l, __bkt_count_hint, __hf, __eql, __a,
551 __unique_keys{})
552 { }
553
554 _Hashtable(initializer_list<value_type> __l,
555 size_type __bkt_count_hint = 0,
556 const _Hash& __hf = _Hash(),
557 const key_equal& __eql = key_equal(),
558 const allocator_type& __a = allocator_type())
559 : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
560 __hf, __eql, __a, __unique_keys{})
561 { }
562
563 _Hashtable&
564 operator=(const _Hashtable& __ht);
565
566 _Hashtable&
567 operator=(_Hashtable&& __ht)
568 noexcept(__node_alloc_traits::_S_nothrow_move()
569 && is_nothrow_move_assignable<_Hash>::value
570 && is_nothrow_move_assignable<_Equal>::value)
571 {
572 constexpr bool __move_storage =
573 __node_alloc_traits::_S_propagate_on_move_assign()
574 || __node_alloc_traits::_S_always_equal();
575 _M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
576 return *this;
577 }
578
579#pragma GCC diagnostic push
580#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
581 _Hashtable&
582 operator=(initializer_list<value_type> __l)
583 {
584 using __reuse_or_alloc_node_gen_t =
585 __detail::_ReuseOrAllocNode<__node_alloc_type>;
586
587 __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
588 _M_before_begin._M_nxt = nullptr;
589 clear();
590
591 // We assume that all elements of __l are likely to be inserted.
592 auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
593
594 // Excess buckets might have been intentionally reserved by the user,
595 // so rehash if we need to grow, but don't shrink.
596 if (_M_bucket_count < __l_bkt_count)
597 rehash(__l_bkt_count);
598
599 __hash_code __code;
600 size_type __bkt;
601 for (auto& __e : __l)
602 {
603 const key_type& __k = _ExtractKey{}(__e);
604
605 if constexpr (__unique_keys::value)
606 {
607 if (auto __loc = _M_locate(__k))
608 continue; // Found existing element with equivalent key
609 else
610 {
611 __code = __loc._M_hash_code;
612 __bkt = __loc._M_bucket_index;
613 }
614 }
615 else
616 {
617 __code = this->_M_hash_code(__k);
618 __bkt = _M_bucket_index(__code);
619 }
620
621 _M_insert_unique_node(__bkt, __code, __roan(__e));
622 }
623
624 return *this;
625 }
626#pragma GCC diagnostic pop
627
628 ~_Hashtable() noexcept;
629
630 void
631 swap(_Hashtable&)
632 noexcept(__and_<__is_nothrow_swappable<_Hash>,
633 __is_nothrow_swappable<_Equal>>::value);
634
635 // Basic container operations
636 iterator
637 begin() noexcept
638 { return iterator(_M_begin()); }
639
640 const_iterator
641 begin() const noexcept
642 { return const_iterator(_M_begin()); }
643
644 iterator
645 end() noexcept
646 { return iterator(nullptr); }
647
648 const_iterator
649 end() const noexcept
650 { return const_iterator(nullptr); }
651
652 const_iterator
653 cbegin() const noexcept
654 { return const_iterator(_M_begin()); }
655
656 const_iterator
657 cend() const noexcept
658 { return const_iterator(nullptr); }
659
660 size_type
661 size() const noexcept
662 { return _M_element_count; }
663
664 _GLIBCXX_NODISCARD bool
665 empty() const noexcept
666 { return size() == 0; }
667
668 allocator_type
669 get_allocator() const noexcept
670 { return allocator_type(this->_M_node_allocator()); }
671
672 size_type
673 max_size() const noexcept
674 { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
675
676 // Observers
677 key_equal
678 key_eq() const
679 { return this->_M_eq(); }
680
681 // hash_function, if present, comes from _Hash_code_base.
682
683 // Bucket operations
684 size_type
685 bucket_count() const noexcept
686 { return _M_bucket_count; }
687
688 size_type
689 max_bucket_count() const noexcept
690 { return max_size(); }
691
692 size_type
693 bucket_size(size_type __bkt) const
694 { return std::distance(begin(__bkt), end(__bkt)); }
695
696 size_type
697 bucket(const key_type& __k) const
698 { return _M_bucket_index(this->_M_hash_code(__k)); }
699
700 local_iterator
701 begin(size_type __bkt)
702 {
703 return local_iterator(*this, _M_bucket_begin(__bkt),
704 __bkt, _M_bucket_count);
705 }
706
707 local_iterator
708 end(size_type __bkt)
709 { return local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
710
711 const_local_iterator
712 begin(size_type __bkt) const
713 {
714 return const_local_iterator(*this, _M_bucket_begin(__bkt),
715 __bkt, _M_bucket_count);
716 }
717
718 const_local_iterator
719 end(size_type __bkt) const
720 { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
721
722 // DR 691.
723 const_local_iterator
724 cbegin(size_type __bkt) const
725 {
726 return const_local_iterator(*this, _M_bucket_begin(__bkt),
727 __bkt, _M_bucket_count);
728 }
729
730 const_local_iterator
731 cend(size_type __bkt) const
732 { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
733
734 float
735 load_factor() const noexcept
736 {
737 return static_cast<float>(size()) / static_cast<float>(bucket_count());
738 }
739
740 // max_load_factor, if present, comes from _Rehash_base.
741
742 // Generalization of max_load_factor. Extension, not found in
743 // TR1. Only useful if _RehashPolicy is something other than
744 // the default.
745 const _RehashPolicy&
746 __rehash_policy() const
747 { return _M_rehash_policy; }
748
749 void
750 __rehash_policy(const _RehashPolicy& __pol)
751 { _M_rehash_policy = __pol; }
752
753 // Lookup.
754 iterator
755 find(const key_type& __k);
756
757 const_iterator
758 find(const key_type& __k) const;
759
760 size_type
761 count(const key_type& __k) const;
762
764 equal_range(const key_type& __k);
765
767 equal_range(const key_type& __k) const;
768
769#ifdef __glibcxx_generic_unordered_lookup // C++ >= 20 && HOSTED
770 template<typename _Kt,
771 typename = __has_is_transparent_t<_Hash, _Kt>,
772 typename = __has_is_transparent_t<_Equal, _Kt>>
773 iterator
774 _M_find_tr(const _Kt& __k);
775
776 template<typename _Kt,
777 typename = __has_is_transparent_t<_Hash, _Kt>,
778 typename = __has_is_transparent_t<_Equal, _Kt>>
779 const_iterator
780 _M_find_tr(const _Kt& __k) const;
781
782 template<typename _Kt,
783 typename = __has_is_transparent_t<_Hash, _Kt>,
784 typename = __has_is_transparent_t<_Equal, _Kt>>
785 size_type
786 _M_count_tr(const _Kt& __k) const;
787
788 template<typename _Kt,
789 typename = __has_is_transparent_t<_Hash, _Kt>,
790 typename = __has_is_transparent_t<_Equal, _Kt>>
791 pair<iterator, iterator>
792 _M_equal_range_tr(const _Kt& __k);
793
794 template<typename _Kt,
795 typename = __has_is_transparent_t<_Hash, _Kt>,
796 typename = __has_is_transparent_t<_Equal, _Kt>>
797 pair<const_iterator, const_iterator>
798 _M_equal_range_tr(const _Kt& __k) const;
799#endif // __glibcxx_generic_unordered_lookup
800
801 private:
802 // Bucket index computation helpers.
803 size_type
804 _M_bucket_index(const __node_value_type& __n) const noexcept
805 { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
806
807 size_type
808 _M_bucket_index(__hash_code __c) const
809 { return __hash_code_base::_M_bucket_index(__c, _M_bucket_count); }
810
811 // Find and insert helper functions and types
812
813 // Find the node before the one matching the criteria.
814 __node_base_ptr
815 _M_find_before_node(size_type, const key_type&, __hash_code) const;
816
817 template<typename _Kt>
818 __node_base_ptr
819 _M_find_before_node_tr(size_type, const _Kt&, __hash_code) const;
820
821 // A pointer to a particular node and/or a hash code and bucket index
822 // where such a node would be found in the container.
823 struct __location_type
824 {
825 // True if _M_node() is a valid node pointer.
826 explicit operator bool() const noexcept
827 { return static_cast<bool>(_M_before); }
828
829 // An iterator that refers to the node, or end().
830 explicit operator iterator() const noexcept
831 { return iterator(_M_node()); }
832
833 // A const_iterator that refers to the node, or cend().
834 explicit operator const_iterator() const noexcept
835 { return const_iterator(_M_node()); }
836
837 // A pointer to the node, or null.
838 __node_ptr _M_node() const
839 {
840 if (_M_before)
841 return static_cast<__node_ptr>(_M_before->_M_nxt);
842 return __node_ptr();
843 }
844
845 __node_base_ptr _M_before{}; // Must only be used to get _M_nxt
846 __hash_code _M_hash_code{}; // Only valid if _M_bucket_index != -1
847 size_type _M_bucket_index = size_type(-1);
848 };
849
850 // Adaptive lookup to find key, or which bucket it would be in.
851 // For a container smaller than the small size threshold use a linear
852 // search through the whole container, just testing for equality.
853 // Otherwise, calculate the hash code and bucket index for the key,
854 // and search in that bucket.
855 // The return value will have a pointer to the node _before_ the first
856 // node matching the key, if any such node exists. Returning the node
857 // before the desired one allows the result to be used for erasure.
858 // If no matching element is present, the hash code and bucket for the
859 // key will be set, allowing a new node to be inserted at that location.
860 // (The hash code and bucket might also be set when a node is found.)
861 // The _M_before pointer might point to _M_before_begin, so must not be
862 // cast to __node_ptr, and it must not be used to modify *_M_before
863 // except in non-const member functions, such as erase.
864 __location_type
865 _M_locate(const key_type& __k) const;
866
867 __node_ptr
868 _M_find_node(size_type __bkt, const key_type& __key,
869 __hash_code __c) const
870 {
871 if (__node_base_ptr __before_n = _M_find_before_node(__bkt, __key, __c))
872 return static_cast<__node_ptr>(__before_n->_M_nxt);
873 return nullptr;
874 }
875
876 template<typename _Kt>
877 __node_ptr
878 _M_find_node_tr(size_type __bkt, const _Kt& __key,
879 __hash_code __c) const
880 {
881 if (auto __before_n = _M_find_before_node_tr(__bkt, __key, __c))
882 return static_cast<__node_ptr>(__before_n->_M_nxt);
883 return nullptr;
884 }
885
886 // Insert a node at the beginning of a bucket.
887 void
888 _M_insert_bucket_begin(size_type __bkt, __node_ptr __node)
889 {
890 if (_M_buckets[__bkt])
891 {
892 // Bucket is not empty, we just need to insert the new node
893 // after the bucket before begin.
894 __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
895 _M_buckets[__bkt]->_M_nxt = __node;
896 }
897 else
898 {
899 // The bucket is empty, the new node is inserted at the
900 // beginning of the singly-linked list and the bucket will
901 // contain _M_before_begin pointer.
902 __node->_M_nxt = _M_before_begin._M_nxt;
903 _M_before_begin._M_nxt = __node;
904
905 if (__node->_M_nxt)
906 // We must update former begin bucket that is pointing to
907 // _M_before_begin.
908 _M_buckets[_M_bucket_index(*__node->_M_next())] = __node;
909
910 _M_buckets[__bkt] = &_M_before_begin;
911 }
912 }
913
914 // Remove the bucket first node
915 void
916 _M_remove_bucket_begin(size_type __bkt, __node_ptr __next_n,
917 size_type __next_bkt)
918 {
919 if (!__next_n)
920 _M_buckets[__bkt] = nullptr;
921 else if (__next_bkt != __bkt)
922 {
923 _M_buckets[__next_bkt] = _M_buckets[__bkt];
924 _M_buckets[__bkt] = nullptr;
925 }
926 }
927
928 // Get the node before __n in the bucket __bkt
929 __node_base_ptr
930 _M_get_previous_node(size_type __bkt, __node_ptr __n);
931
932 pair<__node_ptr, __hash_code>
933 _M_compute_hash_code(__node_ptr __hint, const key_type& __k) const;
934
935 // Insert node __n with hash code __code, in bucket __bkt (or another
936 // bucket if rehashing is needed).
937 // Assumes no element with equivalent key is already present.
938 // Takes ownership of __n if insertion succeeds, throws otherwise.
939 // __n_elt is an estimated number of elements we expect to insert,
940 // used as a hint for rehashing when inserting a range.
941 iterator
942 _M_insert_unique_node(size_type __bkt, __hash_code,
943 __node_ptr __n, size_type __n_elt = 1);
944
945 // Insert node __n with key __k and hash code __code.
946 // Takes ownership of __n if insertion succeeds, throws otherwise.
947 iterator
948 _M_insert_multi_node(__node_ptr __hint,
949 __hash_code __code, __node_ptr __n);
950
951 template<typename... _Args>
953 _M_emplace_uniq(_Args&&... __args);
954
955#pragma GCC diagnostic push
956#pragma GCC diagnostic ignored "-Wc++14-extensions" // variable templates
957 template<typename _Arg, typename _DArg = __remove_cvref_t<_Arg>,
958 typename = _ExtractKey>
959 static constexpr bool __is_key_type = false;
960
961 template<typename _Arg>
962 static constexpr bool
963 __is_key_type<_Arg, key_type, __detail::_Identity> = true;
964
965 template<typename _Arg, typename _Arg1, typename _Arg2>
966 static constexpr bool
967 __is_key_type<_Arg, pair<_Arg1, _Arg2>, __detail::_Select1st>
968 = is_same<__remove_cvref_t<_Arg1>, key_type>::value;
969#pragma GCC diagnostic pop
970
971 template<typename... _Args>
972 iterator
973 _M_emplace_multi(const_iterator, _Args&&... __args);
974
975 iterator
976 _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n);
977
978 template<typename _InputIterator>
979 void
980 _M_insert_range_multi(_InputIterator __first, _InputIterator __last);
981
982 public:
983#pragma GCC diagnostic push
984#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
985 // Emplace
986 template<typename... _Args>
987 __ireturn_type
988 emplace(_Args&&... __args)
989 {
990 if constexpr (__unique_keys::value)
991 return _M_emplace_uniq(std::forward<_Args>(__args)...);
992 else
993 return _M_emplace_multi(cend(), std::forward<_Args>(__args)...);
994 }
995
996 template<typename... _Args>
997 iterator
998 emplace_hint(const_iterator __hint, _Args&&... __args)
999 {
1000 if constexpr (__unique_keys::value)
1001 return _M_emplace_uniq(std::forward<_Args>(__args)...).first;
1002 else
1003 return _M_emplace_multi(__hint, std::forward<_Args>(__args)...);
1004 }
1005
1006 // Insert
1007 __ireturn_type
1008 insert(const value_type& __v)
1009 {
1010 if constexpr (__unique_keys::value)
1011 return _M_emplace_uniq(__v);
1012 else
1013 return _M_emplace_multi(cend(), __v);
1014 }
1015
1016 iterator
1017 insert(const_iterator __hint, const value_type& __v)
1018 {
1019 if constexpr (__unique_keys::value)
1020 return _M_emplace_uniq(__v).first;
1021 else
1022 return _M_emplace_multi(__hint, __v);
1023 }
1024
1025 __ireturn_type
1026 insert(value_type&& __v)
1027 {
1028 if constexpr (__unique_keys::value)
1029 return _M_emplace_uniq(std::move(__v));
1030 else
1031 return _M_emplace_multi(cend(), std::move(__v));
1032 }
1033
1034 iterator
1035 insert(const_iterator __hint, value_type&& __v)
1036 {
1037 if constexpr (__unique_keys::value)
1038 return _M_emplace_uniq(std::move(__v)).first;
1039 else
1040 return _M_emplace_multi(__hint, std::move(__v));
1041 }
1042
1043#ifdef __glibcxx_unordered_map_try_emplace // C++ >= 17 && HOSTED
1044 template<typename _KType, typename... _Args>
1046 try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
1047 {
1048 __hash_code __code;
1049 size_type __bkt;
1050 if (auto __loc = _M_locate(__k))
1051 return { iterator(__loc), false };
1052 else
1053 {
1054 __code = __loc._M_hash_code;
1055 __bkt = __loc._M_bucket_index;
1056 }
1057
1058 _Scoped_node __node {
1059 this,
1061 std::forward_as_tuple(std::forward<_KType>(__k)),
1062 std::forward_as_tuple(std::forward<_Args>(__args)...)
1063 };
1064 auto __it = _M_insert_unique_node(__bkt, __code, __node._M_node);
1065 __node._M_node = nullptr;
1066 return { __it, true };
1067 }
1068#endif
1069
1070 void
1071 insert(initializer_list<value_type> __l)
1072 { this->insert(__l.begin(), __l.end()); }
1073
1074 template<typename _InputIterator>
1075 void
1076 insert(_InputIterator __first, _InputIterator __last)
1077 {
1078 if constexpr (__unique_keys::value)
1079 for (; __first != __last; ++__first)
1080 _M_emplace_uniq(*__first);
1081 else
1082 return _M_insert_range_multi(__first, __last);
1083 }
1084
1085 // This overload is only defined for maps, not sets.
1086 template<typename _Pair,
1087 typename = _Require<__not_<is_same<_Key, _Value>>,
1088 is_constructible<value_type, _Pair&&>>>
1089 __ireturn_type
1090 insert(_Pair&& __v)
1091 {
1092 if constexpr (__unique_keys::value)
1093 return _M_emplace_uniq(std::forward<_Pair>(__v));
1094 else
1095 return _M_emplace_multi(cend(), std::forward<_Pair>(__v));
1096 }
1097
1098 // This overload is only defined for maps, not sets.
1099 template<typename _Pair,
1100 typename = _Require<__not_<is_same<_Key, _Value>>,
1101 is_constructible<value_type, _Pair&&>>>
1102 iterator
1103 insert(const_iterator __hint, _Pair&& __v)
1104 {
1105 if constexpr (__unique_keys::value)
1106 return _M_emplace_uniq(std::forward<_Pair>(__v));
1107 else
1108 return _M_emplace_multi(__hint, std::forward<_Pair>(__v));
1109 }
1110#pragma GCC diagnostic pop
1111
1112 // Erase
1113 iterator
1114 erase(const_iterator);
1115
1116 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1117 // 2059. C++0x ambiguity problem with map::erase
1118 iterator
1119 erase(iterator __it)
1120 { return erase(const_iterator(__it)); }
1121
1122 size_type
1123 erase(const key_type& __k);
1124
1125 iterator
1126 erase(const_iterator, const_iterator);
1127
1128 void
1129 clear() noexcept;
1130
1131 // Set number of buckets keeping it appropriate for container's number
1132 // of elements.
1133 void rehash(size_type __bkt_count);
1134
1135 // DR 1189.
1136 // reserve, if present, comes from _Rehash_base.
1137
1138#if __glibcxx_node_extract // >= C++17 && HOSTED
1139 /// Re-insert an extracted node into a container with unique keys.
1140 insert_return_type
1141 _M_reinsert_node(node_type&& __nh)
1142 {
1143 insert_return_type __ret;
1144 if (__nh.empty())
1145 __ret.position = end();
1146 else
1147 {
1148 __glibcxx_assert(get_allocator() == __nh.get_allocator());
1149
1150 if (auto __loc = _M_locate(__nh._M_key()))
1151 {
1152 __ret.node = std::move(__nh);
1153 __ret.position = iterator(__loc);
1154 __ret.inserted = false;
1155 }
1156 else
1157 {
1158 auto __code = __loc._M_hash_code;
1159 auto __bkt = __loc._M_bucket_index;
1160 __ret.position
1161 = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
1162 __ret.inserted = true;
1163 __nh.release();
1164 }
1165 }
1166 return __ret;
1167 }
1168
1169 /// Re-insert an extracted node into a container with equivalent keys.
1170 iterator
1171 _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
1172 {
1173 if (__nh.empty())
1174 return end();
1175
1176 __glibcxx_assert(get_allocator() == __nh.get_allocator());
1177
1178 const key_type& __k = __nh._M_key();
1179 auto __code = this->_M_hash_code(__k);
1180 auto __ret
1181 = _M_insert_multi_node(__hint._M_cur, __code, __nh._M_ptr);
1182 __nh.release();
1183 return __ret;
1184 }
1185
1186 private:
1187 node_type
1188 _M_extract_node(size_t __bkt, __node_base_ptr __prev_n)
1189 {
1190 __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
1191 if (__prev_n == _M_buckets[__bkt])
1192 _M_remove_bucket_begin(__bkt, __n->_M_next(),
1193 __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
1194 else if (__n->_M_nxt)
1195 {
1196 size_type __next_bkt = _M_bucket_index(*__n->_M_next());
1197 if (__next_bkt != __bkt)
1198 _M_buckets[__next_bkt] = __prev_n;
1199 }
1200
1201 __prev_n->_M_nxt = __n->_M_nxt;
1202 __n->_M_nxt = nullptr;
1203 --_M_element_count;
1204 return { __n, this->_M_node_allocator() };
1205 }
1206
1207 // Only use the possibly cached node's hash code if its hash function
1208 // _H2 matches _Hash and is stateless. Otherwise recompute it using _Hash.
1209 template<typename _H2>
1210 __hash_code
1211 _M_src_hash_code(const _H2&, const key_type& __k,
1212 const __node_value_type& __src_n) const
1213 {
1214 if constexpr (std::is_same_v<_H2, _Hash>)
1215 if constexpr (std::is_empty_v<_Hash>)
1216 return this->_M_hash_code(__src_n);
1217
1218 return this->_M_hash_code(__k);
1219 }
1220
1221 public:
1222 // Extract a node.
1223 node_type
1224 extract(const_iterator __pos)
1225 {
1226 size_t __bkt = _M_bucket_index(*__pos._M_cur);
1227 return _M_extract_node(__bkt,
1228 _M_get_previous_node(__bkt, __pos._M_cur));
1229 }
1230
1231 /// Extract a node.
1232 node_type
1233 extract(const _Key& __k)
1234 {
1235 node_type __nh;
1236 __hash_code __code = this->_M_hash_code(__k);
1237 std::size_t __bkt = _M_bucket_index(__code);
1238 if (__node_base_ptr __prev_node = _M_find_before_node(__bkt, __k, __code))
1239 __nh = _M_extract_node(__bkt, __prev_node);
1240 return __nh;
1241 }
1242
1243 /// Merge from another container of the same type.
1244 void
1245 _M_merge_unique(_Hashtable& __src)
1246 {
1247 __glibcxx_assert(get_allocator() == __src.get_allocator());
1248
1249 auto __n_elt = __src.size();
1250 size_type __first = 1;
1251 // For a container of identical type we can use its private members.
1252 auto __p = static_cast<__node_ptr>(&__src._M_before_begin);
1253 while (__n_elt--)
1254 {
1255 const auto __prev = __p;
1256 __p = __p->_M_next();
1257 const auto& __node = *__p;
1258 const key_type& __k = _ExtractKey{}(__node._M_v());
1259 auto __loc = _M_locate(__k);
1260 if (__loc)
1261 continue;
1262
1263 size_type __src_bkt
1264 = __src._M_bucket_index(__src.hash_function()(__k));
1265 auto __nh = __src._M_extract_node(__src_bkt, __prev);
1266 _M_insert_unique_node(__loc._M_bucket_index, __loc._M_hash_code,
1267 __nh._M_ptr, __first * __n_elt + 1);
1268 __nh.release();
1269 __first = 0;
1270 __p = __prev;
1271 }
1272 }
1273
1274 /// Merge from a compatible container into one with unique keys.
1275 template<typename _Compatible_Hashtable>
1276 void
1277 _M_merge_unique(_Compatible_Hashtable& __src)
1278 {
1279 static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1280 node_type>, "Node types are compatible");
1281 __glibcxx_assert(get_allocator() == __src.get_allocator());
1282
1283 auto __n_elt = __src.size();
1284 size_type __first = 1;
1285 // For a compatible container we can only use the public API,
1286 // so cbegin(), cend(), hash_function(), and extract(iterator).
1287 for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1288 {
1289 --__n_elt;
1290 auto __pos = __i++;
1291 const key_type& __k = _ExtractKey{}(*__pos);
1292 const auto __loc = _M_locate(__k);
1293 if (__loc)
1294 continue;
1295
1296 auto __nh = __src.extract(__pos);
1297 _M_insert_unique_node(__loc._M_bucket_index,
1298 __loc._M_hash_code, __nh._M_ptr,
1299 __first * __n_elt + 1);
1300 __nh.release();
1301 __first = 0;
1302 }
1303 }
1304
1305 /// Merge from another container of the same type.
1306 void
1307 _M_merge_multi(_Hashtable& __src)
1308 {
1309 __glibcxx_assert(get_allocator() == __src.get_allocator());
1310
1311 if (__src.size() == 0) [[__unlikely__]]
1312 return;
1313
1314 __node_ptr __hint = nullptr;
1315 this->reserve(size() + __src.size());
1316 // For a container of identical type we can use its private members.
1317 auto __prev = static_cast<__node_ptr>(&__src._M_before_begin);
1318 do
1319 {
1320 const auto& __node = *__prev->_M_next();
1321 const key_type& __k = _ExtractKey{}(__node._M_v());
1322 __hash_code __code = this->_M_hash_code(__k);
1323 size_type __src_bkt = __src._M_bucket_index(__node);
1324 auto __nh = __src._M_extract_node(__src_bkt, __prev);
1325 __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
1326 __nh.release();
1327 }
1328 while (__prev->_M_nxt != nullptr);
1329 }
1330
1331 /// Merge from a compatible container into one with equivalent keys.
1332 template<typename _Compatible_Hashtable>
1333 void
1334 _M_merge_multi(_Compatible_Hashtable& __src)
1335 {
1336 static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1337 node_type>, "Node types are compatible");
1338 __glibcxx_assert(get_allocator() == __src.get_allocator());
1339
1340 __node_ptr __hint = nullptr;
1341 this->reserve(size() + __src.size());
1342 // For a compatible container we can only use the public API,
1343 // so cbegin(), cend(), hash_function(), and extract(iterator).
1344 for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1345 {
1346 auto __pos = __i++;
1347 const key_type& __k = _ExtractKey{}(*__pos);
1348 __hash_code __code
1349 = _M_src_hash_code(__src.hash_function(), __k, *__pos._M_cur);
1350 auto __nh = __src.extract(__pos);
1351 __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
1352 __nh.release();
1353 }
1354 }
1355#endif // C++17 __glibcxx_node_extract
1356
1357 bool
1358 _M_equal(const _Hashtable& __other) const;
1359
1360 private:
1361 // Helper rehash method used when keys are unique.
1362 void _M_rehash(size_type __bkt_count, true_type __uks);
1363
1364 // Helper rehash method used when keys can be non-unique.
1365 void _M_rehash(size_type __bkt_count, false_type __uks);
1366 };
1367
1368 // Definitions of class template _Hashtable's out-of-line member functions.
1369 template<typename _Key, typename _Value, typename _Alloc,
1370 typename _ExtractKey, typename _Equal,
1371 typename _Hash, typename _RangeHash, typename _Unused,
1372 typename _RehashPolicy, typename _Traits>
1373 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1374 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1375 _Hashtable(size_type __bkt_count_hint,
1376 const _Hash& __h, const _Equal& __eq, const allocator_type& __a)
1377 : _Hashtable(__h, __eq, __a)
1378 {
1379 auto __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count_hint);
1380 if (__bkt_count > _M_bucket_count)
1381 {
1382 _M_buckets = _M_allocate_buckets(__bkt_count);
1383 _M_bucket_count = __bkt_count;
1384 }
1385 }
1386
1387 template<typename _Key, typename _Value, typename _Alloc,
1388 typename _ExtractKey, typename _Equal,
1389 typename _Hash, typename _RangeHash, typename _Unused,
1390 typename _RehashPolicy, typename _Traits>
1391 template<typename _InputIterator>
1392 inline
1393 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1394 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1395 _Hashtable(_InputIterator __f, _InputIterator __l,
1396 size_type __bkt_count_hint,
1397 const _Hash& __h, const _Equal& __eq,
1398 const allocator_type& __a, true_type /* __uks */)
1399 : _Hashtable(__bkt_count_hint, __h, __eq, __a)
1400 { this->insert(__f, __l); }
1401
1402 template<typename _Key, typename _Value, typename _Alloc,
1403 typename _ExtractKey, typename _Equal,
1404 typename _Hash, typename _RangeHash, typename _Unused,
1405 typename _RehashPolicy, typename _Traits>
1406 template<typename _InputIterator>
1407 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1408 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1409 _Hashtable(_InputIterator __f, _InputIterator __l,
1410 size_type __bkt_count_hint,
1411 const _Hash& __h, const _Equal& __eq,
1412 const allocator_type& __a, false_type __uks)
1413 : _Hashtable(__h, __eq, __a)
1414 {
1415 auto __nb_elems = __detail::__distance_fw(__f, __l);
1416 auto __bkt_count =
1417 _M_rehash_policy._M_next_bkt(
1418 std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
1419 __bkt_count_hint));
1420
1421 if (__bkt_count > _M_bucket_count)
1422 {
1423 _M_buckets = _M_allocate_buckets(__bkt_count);
1424 _M_bucket_count = __bkt_count;
1425 }
1426
1427 for (; __f != __l; ++__f)
1428 _M_emplace_multi(cend(), *__f);
1429 }
1430
1431 template<typename _Key, typename _Value, typename _Alloc,
1432 typename _ExtractKey, typename _Equal,
1433 typename _Hash, typename _RangeHash, typename _Unused,
1434 typename _RehashPolicy, typename _Traits>
1435 auto
1436 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1437 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1438 operator=(const _Hashtable& __ht)
1439 -> _Hashtable&
1440 {
1441 if (&__ht == this)
1442 return *this;
1443
1444 if (__node_alloc_traits::_S_propagate_on_copy_assign())
1445 {
1446 auto& __this_alloc = this->_M_node_allocator();
1447 auto& __that_alloc = __ht._M_node_allocator();
1448 if (!__node_alloc_traits::_S_always_equal()
1449 && __this_alloc != __that_alloc)
1450 {
1451 // Replacement allocator cannot free existing storage.
1452 this->_M_deallocate_nodes(_M_begin());
1453 _M_before_begin._M_nxt = nullptr;
1454 _M_deallocate_buckets();
1455 _M_buckets = nullptr;
1456 std::__alloc_on_copy(__this_alloc, __that_alloc);
1457 __hashtable_base::operator=(__ht);
1458 _M_bucket_count = __ht._M_bucket_count;
1459 _M_element_count = __ht._M_element_count;
1460 _M_rehash_policy = __ht._M_rehash_policy;
1461
1462 struct _Guard
1463 {
1464 ~_Guard() { if (_M_ht) _M_ht->_M_reset(); }
1465 _Hashtable* _M_ht;
1466 };
1467 // If _M_assign exits via an exception it will have deallocated
1468 // all memory. This guard will ensure *this is in a usable state.
1469 _Guard __guard{this};
1470 _M_assign(__ht);
1471 __guard._M_ht = nullptr;
1472 return *this;
1473 }
1474 std::__alloc_on_copy(__this_alloc, __that_alloc);
1475 }
1476
1477 // Reuse allocated buckets and nodes.
1478 _M_assign_elements(__ht);
1479 return *this;
1480 }
1481
1482 template<typename _Key, typename _Value, typename _Alloc,
1483 typename _ExtractKey, typename _Equal,
1484 typename _Hash, typename _RangeHash, typename _Unused,
1485 typename _RehashPolicy, typename _Traits>
1486 template<typename _Ht>
1487 void
1488 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1489 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1490 _M_assign_elements(_Ht&& __ht)
1491 {
1492 using __reuse_or_alloc_node_gen_t =
1493 __detail::_ReuseOrAllocNode<__node_alloc_type>;
1494
1495 __buckets_ptr __former_buckets = nullptr;
1496 std::size_t __former_bucket_count = _M_bucket_count;
1497 __rehash_guard_t __rehash_guard(_M_rehash_policy);
1498
1499 if (_M_bucket_count != __ht._M_bucket_count)
1500 {
1501 __former_buckets = _M_buckets;
1502 _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1503 _M_bucket_count = __ht._M_bucket_count;
1504 }
1505 else
1506 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
1507
1508 __try
1509 {
1510 __hashtable_base::operator=(std::forward<_Ht>(__ht));
1511 _M_element_count = __ht._M_element_count;
1512 _M_rehash_policy = __ht._M_rehash_policy;
1513 __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
1514 _M_before_begin._M_nxt = nullptr;
1515 _M_assign(std::forward<_Ht>(__ht), __roan);
1516 if (__former_buckets)
1517 _M_deallocate_buckets(__former_buckets, __former_bucket_count);
1518 __rehash_guard._M_guarded_obj = nullptr;
1519 }
1520 __catch(...)
1521 {
1522 if (__former_buckets)
1523 {
1524 // Restore previous buckets.
1525 _M_deallocate_buckets();
1526 _M_buckets = __former_buckets;
1527 _M_bucket_count = __former_bucket_count;
1528 }
1529 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
1530 __throw_exception_again;
1531 }
1532 }
1533
1534 template<typename _Key, typename _Value, typename _Alloc,
1535 typename _ExtractKey, typename _Equal,
1536 typename _Hash, typename _RangeHash, typename _Unused,
1537 typename _RehashPolicy, typename _Traits>
1538 template<typename _Ht, typename _NodeGenerator>
1539 void
1540 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1541 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1542 _M_assign(_Ht&& __ht, _NodeGenerator& __node_gen)
1543 {
1544 struct _Guard
1545 {
1546 ~_Guard()
1547 {
1548 if (_M_ht)
1549 {
1550 _M_ht->clear();
1551 if (_M_dealloc_buckets)
1552 _M_ht->_M_deallocate_buckets();
1553 }
1554 }
1555 _Hashtable* _M_ht = nullptr;
1556 bool _M_dealloc_buckets = false;
1557 };
1558 _Guard __guard;
1559
1560 if (!_M_buckets)
1561 {
1562 _M_buckets = _M_allocate_buckets(_M_bucket_count);
1563 __guard._M_dealloc_buckets = true;
1564 }
1565
1566 if (!__ht._M_before_begin._M_nxt)
1567 return;
1568
1569 __guard._M_ht = this;
1570
1571 using _FromVal = __conditional_t<is_lvalue_reference<_Ht>::value,
1572 const value_type&, value_type&&>;
1573
1574 // First deal with the special first node pointed to by
1575 // _M_before_begin.
1576 __node_ptr __ht_n = __ht._M_begin();
1577 __node_ptr __this_n
1578 = __node_gen(static_cast<_FromVal>(__ht_n->_M_v()));
1579 this->_M_copy_code(*__this_n, *__ht_n);
1580 _M_update_bbegin(__this_n);
1581
1582 // Then deal with other nodes.
1583 __node_ptr __prev_n = __this_n;
1584 for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
1585 {
1586 __this_n = __node_gen(static_cast<_FromVal>(__ht_n->_M_v()));
1587 __prev_n->_M_nxt = __this_n;
1588 this->_M_copy_code(*__this_n, *__ht_n);
1589 size_type __bkt = _M_bucket_index(*__this_n);
1590 if (!_M_buckets[__bkt])
1591 _M_buckets[__bkt] = __prev_n;
1592 __prev_n = __this_n;
1593 }
1594 __guard._M_ht = nullptr;
1595 }
1596
1597 template<typename _Key, typename _Value, typename _Alloc,
1598 typename _ExtractKey, typename _Equal,
1599 typename _Hash, typename _RangeHash, typename _Unused,
1600 typename _RehashPolicy, typename _Traits>
1601 void
1602 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1603 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1604 _M_reset() noexcept
1605 {
1606 _M_rehash_policy._M_reset();
1607 _M_bucket_count = 1;
1608 _M_single_bucket = nullptr;
1609 _M_buckets = &_M_single_bucket;
1610 _M_before_begin._M_nxt = nullptr;
1611 _M_element_count = 0;
1612 }
1613
1614 template<typename _Key, typename _Value, typename _Alloc,
1615 typename _ExtractKey, typename _Equal,
1616 typename _Hash, typename _RangeHash, typename _Unused,
1617 typename _RehashPolicy, typename _Traits>
1618 void
1619 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1620 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1621 _M_move_assign(_Hashtable&& __ht, true_type)
1622 {
1623 if (__builtin_expect(std::__addressof(__ht) == this, false))
1624 return;
1625
1626 this->_M_deallocate_nodes(_M_begin());
1627 _M_deallocate_buckets();
1628 __hashtable_base::operator=(std::move(__ht));
1629 _M_rehash_policy = __ht._M_rehash_policy;
1630 if (!__ht._M_uses_single_bucket())
1631 _M_buckets = __ht._M_buckets;
1632 else
1633 {
1634 _M_buckets = &_M_single_bucket;
1635 _M_single_bucket = __ht._M_single_bucket;
1636 }
1637
1638 _M_bucket_count = __ht._M_bucket_count;
1639 _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1640 _M_element_count = __ht._M_element_count;
1641 std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1642
1643 // Fix bucket containing the _M_before_begin pointer that can't be moved.
1644 _M_update_bbegin();
1645 __ht._M_reset();
1646 }
1647
1648 template<typename _Key, typename _Value, typename _Alloc,
1649 typename _ExtractKey, typename _Equal,
1650 typename _Hash, typename _RangeHash, typename _Unused,
1651 typename _RehashPolicy, typename _Traits>
1652 void
1653 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1654 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1655 _M_move_assign(_Hashtable&& __ht, false_type)
1656 {
1657 if (__ht._M_node_allocator() == this->_M_node_allocator())
1658 _M_move_assign(std::move(__ht), true_type{});
1659 else
1660 {
1661 // Can't move memory, move elements then.
1662 _M_assign_elements(std::move(__ht));
1663 __ht.clear();
1664 }
1665 }
1666
1667 template<typename _Key, typename _Value, typename _Alloc,
1668 typename _ExtractKey, typename _Equal,
1669 typename _Hash, typename _RangeHash, typename _Unused,
1670 typename _RehashPolicy, typename _Traits>
1671 inline
1672 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1673 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1674 _Hashtable(const _Hashtable& __ht)
1675 : __hashtable_base(__ht),
1676 __map_base(__ht),
1677 __rehash_base(__ht),
1678 __hashtable_alloc(
1679 __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1680 __enable_default_ctor(__ht),
1681 _M_buckets(nullptr),
1682 _M_bucket_count(__ht._M_bucket_count),
1683 _M_element_count(__ht._M_element_count),
1684 _M_rehash_policy(__ht._M_rehash_policy)
1685 {
1686 _M_assign(__ht);
1687 }
1688
1689 template<typename _Key, typename _Value, typename _Alloc,
1690 typename _ExtractKey, typename _Equal,
1691 typename _Hash, typename _RangeHash, typename _Unused,
1692 typename _RehashPolicy, typename _Traits>
1693 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1694 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1695 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1696 true_type /* alloc always equal */)
1697 noexcept(_S_nothrow_move())
1698 : __hashtable_base(__ht),
1699 __map_base(__ht),
1700 __rehash_base(__ht),
1701 __hashtable_alloc(std::move(__a)),
1702 __enable_default_ctor(__ht),
1703 _M_buckets(__ht._M_buckets),
1704 _M_bucket_count(__ht._M_bucket_count),
1705 _M_before_begin(__ht._M_before_begin._M_nxt),
1706 _M_element_count(__ht._M_element_count),
1707 _M_rehash_policy(__ht._M_rehash_policy)
1708 {
1709 // Update buckets if __ht is using its single bucket.
1710 if (__ht._M_uses_single_bucket())
1711 {
1712 _M_buckets = &_M_single_bucket;
1713 _M_single_bucket = __ht._M_single_bucket;
1714 }
1715
1716 // Fix bucket containing the _M_before_begin pointer that can't be moved.
1717 _M_update_bbegin();
1718
1719 __ht._M_reset();
1720 }
1721
1722 template<typename _Key, typename _Value, typename _Alloc,
1723 typename _ExtractKey, typename _Equal,
1724 typename _Hash, typename _RangeHash, typename _Unused,
1725 typename _RehashPolicy, typename _Traits>
1726 inline
1727 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1728 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1729 _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1730 : __hashtable_base(__ht),
1731 __map_base(__ht),
1732 __rehash_base(__ht),
1733 __hashtable_alloc(__node_alloc_type(__a)),
1734 __enable_default_ctor(__ht),
1735 _M_buckets(),
1736 _M_bucket_count(__ht._M_bucket_count),
1737 _M_element_count(__ht._M_element_count),
1738 _M_rehash_policy(__ht._M_rehash_policy)
1739 {
1740 _M_assign(__ht);
1741 }
1742
1743 template<typename _Key, typename _Value, typename _Alloc,
1744 typename _ExtractKey, typename _Equal,
1745 typename _Hash, typename _RangeHash, typename _Unused,
1746 typename _RehashPolicy, typename _Traits>
1747 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1748 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1749 _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1750 false_type /* alloc always equal */)
1751 : __hashtable_base(__ht),
1752 __map_base(__ht),
1753 __rehash_base(__ht),
1754 __hashtable_alloc(std::move(__a)),
1755 __enable_default_ctor(__ht),
1756 _M_buckets(nullptr),
1757 _M_bucket_count(__ht._M_bucket_count),
1758 _M_element_count(__ht._M_element_count),
1759 _M_rehash_policy(__ht._M_rehash_policy)
1760 {
1761 if (__ht._M_node_allocator() == this->_M_node_allocator())
1762 {
1763 if (__ht._M_uses_single_bucket())
1764 {
1765 _M_buckets = &_M_single_bucket;
1766 _M_single_bucket = __ht._M_single_bucket;
1767 }
1768 else
1769 _M_buckets = __ht._M_buckets;
1770
1771 // Fix bucket containing the _M_before_begin pointer that can't be
1772 // moved.
1773 _M_update_bbegin(__ht._M_begin());
1774
1775 __ht._M_reset();
1776 }
1777 else
1778 {
1779 using _Fwd_Ht = __conditional_t<
1780 __move_if_noexcept_cond<value_type>::value,
1781 const _Hashtable&, _Hashtable&&>;
1782 _M_assign(std::forward<_Fwd_Ht>(__ht));
1783 __ht.clear();
1784 }
1785 }
1786
1787 template<typename _Key, typename _Value, typename _Alloc,
1788 typename _ExtractKey, typename _Equal,
1789 typename _Hash, typename _RangeHash, typename _Unused,
1790 typename _RehashPolicy, typename _Traits>
1791 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1792 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1793 ~_Hashtable() noexcept
1794 {
1795 // Getting a bucket index from a node shall not throw because it is used
1796 // during the rehash process. This static_assert purpose is limited to usage
1797 // of _Hashtable with _Hashtable_traits requesting non-cached hash code.
1798 // Need a complete type to check this, so do it in the destructor not at
1799 // class scope.
1800 static_assert(noexcept(declval<const __hash_code_base_access&>()
1801 ._M_bucket_index(declval<const __node_value_type&>(),
1802 (std::size_t)0)),
1803 "Cache the hash code or qualify your functors involved"
1804 " in hash code and bucket index computation with noexcept");
1805
1806 this->_M_deallocate_nodes(_M_begin());
1807 _M_deallocate_buckets();
1808 }
1809
1810 template<typename _Key, typename _Value, typename _Alloc,
1811 typename _ExtractKey, typename _Equal,
1812 typename _Hash, typename _RangeHash, typename _Unused,
1813 typename _RehashPolicy, typename _Traits>
1814 void
1815 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1816 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1817 swap(_Hashtable& __x)
1818 noexcept(__and_<__is_nothrow_swappable<_Hash>,
1819 __is_nothrow_swappable<_Equal>>::value)
1820 {
1821 // The only base class with member variables is hash_code_base.
1822 // We define _Hash_code_base::_M_swap because different
1823 // specializations have different members.
1824 this->_M_swap(__x);
1825
1826 std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1827 std::swap(_M_rehash_policy, __x._M_rehash_policy);
1828
1829 // Deal properly with potentially moved instances.
1830 if (this->_M_uses_single_bucket())
1831 {
1832 if (!__x._M_uses_single_bucket())
1833 {
1834 _M_buckets = __x._M_buckets;
1835 __x._M_buckets = &__x._M_single_bucket;
1836 }
1837 }
1838 else if (__x._M_uses_single_bucket())
1839 {
1840 __x._M_buckets = _M_buckets;
1841 _M_buckets = &_M_single_bucket;
1842 }
1843 else
1844 std::swap(_M_buckets, __x._M_buckets);
1845
1846 std::swap(_M_bucket_count, __x._M_bucket_count);
1847 std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1848 std::swap(_M_element_count, __x._M_element_count);
1849 std::swap(_M_single_bucket, __x._M_single_bucket);
1850
1851 // Fix buckets containing the _M_before_begin pointers that can't be
1852 // swapped.
1853 _M_update_bbegin();
1854 __x._M_update_bbegin();
1855 }
1856
1857 template<typename _Key, typename _Value, typename _Alloc,
1858 typename _ExtractKey, typename _Equal,
1859 typename _Hash, typename _RangeHash, typename _Unused,
1860 typename _RehashPolicy, typename _Traits>
1861 auto
1862 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1863 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1864 find(const key_type& __k)
1865 -> iterator
1866 { return iterator(_M_locate(__k)); }
1867
1868 template<typename _Key, typename _Value, typename _Alloc,
1869 typename _ExtractKey, typename _Equal,
1870 typename _Hash, typename _RangeHash, typename _Unused,
1871 typename _RehashPolicy, typename _Traits>
1872 auto
1873 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1874 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1875 find(const key_type& __k) const
1876 -> const_iterator
1877 { return const_iterator(_M_locate(__k)); }
1878
1879#if __cplusplus > 201703L
1880 template<typename _Key, typename _Value, typename _Alloc,
1881 typename _ExtractKey, typename _Equal,
1882 typename _Hash, typename _RangeHash, typename _Unused,
1883 typename _RehashPolicy, typename _Traits>
1884 template<typename _Kt, typename, typename>
1885 auto
1886 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1887 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1888 _M_find_tr(const _Kt& __k)
1889 -> iterator
1890 {
1891 if (size() <= __small_size_threshold())
1892 {
1893 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1894 if (this->_M_key_equals_tr(__k, *__n))
1895 return iterator(__n);
1896 return end();
1897 }
1898
1899 __hash_code __code = this->_M_hash_code_tr(__k);
1900 std::size_t __bkt = _M_bucket_index(__code);
1901 return iterator(_M_find_node_tr(__bkt, __k, __code));
1902 }
1903
1904 template<typename _Key, typename _Value, typename _Alloc,
1905 typename _ExtractKey, typename _Equal,
1906 typename _Hash, typename _RangeHash, typename _Unused,
1907 typename _RehashPolicy, typename _Traits>
1908 template<typename _Kt, typename, typename>
1909 auto
1910 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1911 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1912 _M_find_tr(const _Kt& __k) const
1913 -> const_iterator
1914 {
1915 if (size() <= __small_size_threshold())
1916 {
1917 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1918 if (this->_M_key_equals_tr(__k, *__n))
1919 return const_iterator(__n);
1920 return end();
1921 }
1922
1923 __hash_code __code = this->_M_hash_code_tr(__k);
1924 std::size_t __bkt = _M_bucket_index(__code);
1925 return const_iterator(_M_find_node_tr(__bkt, __k, __code));
1926 }
1927#endif
1928
1929 template<typename _Key, typename _Value, typename _Alloc,
1930 typename _ExtractKey, typename _Equal,
1931 typename _Hash, typename _RangeHash, typename _Unused,
1932 typename _RehashPolicy, typename _Traits>
1933 auto
1934 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1935 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1936 count(const key_type& __k) const
1937 -> size_type
1938 {
1939 auto __it = find(__k);
1940 if (!__it._M_cur)
1941 return 0;
1942
1943 if (__unique_keys::value)
1944 return 1;
1945
1946 size_type __result = 1;
1947 for (auto __ref = __it++;
1948 __it._M_cur && this->_M_node_equals(*__ref._M_cur, *__it._M_cur);
1949 ++__it)
1950 ++__result;
1951
1952 return __result;
1953 }
1954
1955#if __cplusplus > 201703L
1956 template<typename _Key, typename _Value, typename _Alloc,
1957 typename _ExtractKey, typename _Equal,
1958 typename _Hash, typename _RangeHash, typename _Unused,
1959 typename _RehashPolicy, typename _Traits>
1960 template<typename _Kt, typename, typename>
1961 auto
1962 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1963 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1964 _M_count_tr(const _Kt& __k) const
1965 -> size_type
1966 {
1967 if (size() <= __small_size_threshold())
1968 {
1969 size_type __result = 0;
1970 for (auto __n = _M_begin(); __n; __n = __n->_M_next())
1971 {
1972 if (this->_M_key_equals_tr(__k, *__n))
1973 {
1974 ++__result;
1975 continue;
1976 }
1977
1978 if (__result)
1979 break;
1980 }
1981
1982 return __result;
1983 }
1984
1985 __hash_code __code = this->_M_hash_code_tr(__k);
1986 std::size_t __bkt = _M_bucket_index(__code);
1987 auto __n = _M_find_node_tr(__bkt, __k, __code);
1988 if (!__n)
1989 return 0;
1990
1991 iterator __it(__n);
1992 size_type __result = 1;
1993 for (++__it;
1994 __it._M_cur && this->_M_equals_tr(__k, __code, *__it._M_cur);
1995 ++__it)
1996 ++__result;
1997
1998 return __result;
1999 }
2000#endif
2001
2002 template<typename _Key, typename _Value, typename _Alloc,
2003 typename _ExtractKey, typename _Equal,
2004 typename _Hash, typename _RangeHash, typename _Unused,
2005 typename _RehashPolicy, typename _Traits>
2006 auto
2007 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2008 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2009 equal_range(const key_type& __k)
2010 -> pair<iterator, iterator>
2011 {
2012 auto __ite = find(__k);
2013 if (!__ite._M_cur)
2014 return { __ite, __ite };
2015
2016 auto __beg = __ite++;
2017 if (__unique_keys::value)
2018 return { __beg, __ite };
2019
2020 while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
2021 ++__ite;
2022
2023 return { __beg, __ite };
2024 }
2025
2026 template<typename _Key, typename _Value, typename _Alloc,
2027 typename _ExtractKey, typename _Equal,
2028 typename _Hash, typename _RangeHash, typename _Unused,
2029 typename _RehashPolicy, typename _Traits>
2030 auto
2031 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2032 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2033 equal_range(const key_type& __k) const
2034 -> pair<const_iterator, const_iterator>
2035 {
2036 auto __ite = find(__k);
2037 if (!__ite._M_cur)
2038 return { __ite, __ite };
2039
2040 auto __beg = __ite++;
2041 if (__unique_keys::value)
2042 return { __beg, __ite };
2043
2044 while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
2045 ++__ite;
2046
2047 return { __beg, __ite };
2048 }
2049
2050#if __cplusplus > 201703L
2051 template<typename _Key, typename _Value, typename _Alloc,
2052 typename _ExtractKey, typename _Equal,
2053 typename _Hash, typename _RangeHash, typename _Unused,
2054 typename _RehashPolicy, typename _Traits>
2055 template<typename _Kt, typename, typename>
2056 auto
2057 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2058 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2059 _M_equal_range_tr(const _Kt& __k)
2060 -> pair<iterator, iterator>
2061 {
2062 if (size() <= __small_size_threshold())
2063 {
2064 __node_ptr __n, __beg = nullptr;
2065 for (__n = _M_begin(); __n; __n = __n->_M_next())
2066 {
2067 if (this->_M_key_equals_tr(__k, *__n))
2068 {
2069 if (!__beg)
2070 __beg = __n;
2071 continue;
2072 }
2073
2074 if (__beg)
2075 break;
2076 }
2077
2078 return { iterator(__beg), iterator(__n) };
2079 }
2080
2081 __hash_code __code = this->_M_hash_code_tr(__k);
2082 std::size_t __bkt = _M_bucket_index(__code);
2083 auto __n = _M_find_node_tr(__bkt, __k, __code);
2084 iterator __ite(__n);
2085 if (!__n)
2086 return { __ite, __ite };
2087
2088 auto __beg = __ite++;
2089 while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
2090 ++__ite;
2091
2092 return { __beg, __ite };
2093 }
2094
2095 template<typename _Key, typename _Value, typename _Alloc,
2096 typename _ExtractKey, typename _Equal,
2097 typename _Hash, typename _RangeHash, typename _Unused,
2098 typename _RehashPolicy, typename _Traits>
2099 template<typename _Kt, typename, typename>
2100 auto
2101 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2102 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2103 _M_equal_range_tr(const _Kt& __k) const
2104 -> pair<const_iterator, const_iterator>
2105 {
2106 if (size() <= __small_size_threshold())
2107 {
2108 __node_ptr __n, __beg = nullptr;
2109 for (__n = _M_begin(); __n; __n = __n->_M_next())
2110 {
2111 if (this->_M_key_equals_tr(__k, *__n))
2112 {
2113 if (!__beg)
2114 __beg = __n;
2115 continue;
2116 }
2117
2118 if (__beg)
2119 break;
2120 }
2121
2122 return { const_iterator(__beg), const_iterator(__n) };
2123 }
2124
2125 __hash_code __code = this->_M_hash_code_tr(__k);
2126 std::size_t __bkt = _M_bucket_index(__code);
2127 auto __n = _M_find_node_tr(__bkt, __k, __code);
2128 const_iterator __ite(__n);
2129 if (!__n)
2130 return { __ite, __ite };
2131
2132 auto __beg = __ite++;
2133 while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
2134 ++__ite;
2135
2136 return { __beg, __ite };
2137 }
2138#endif
2139
2140 // Find the node before the one whose key compares equal to k in the bucket
2141 // bkt. Return nullptr if no node is found.
2142 template<typename _Key, typename _Value, typename _Alloc,
2143 typename _ExtractKey, typename _Equal,
2144 typename _Hash, typename _RangeHash, typename _Unused,
2145 typename _RehashPolicy, typename _Traits>
2146 auto
2147 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2148 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2149 _M_find_before_node(size_type __bkt, const key_type& __k,
2150 __hash_code __code) const
2151 -> __node_base_ptr
2152 {
2153 __node_base_ptr __prev_p = _M_buckets[__bkt];
2154 if (!__prev_p)
2155 return nullptr;
2156
2157 for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
2158 __p = __p->_M_next())
2159 {
2160 if (this->_M_equals(__k, __code, *__p))
2161 return __prev_p;
2162
2163 if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
2164 break;
2165 __prev_p = __p;
2166 }
2167
2168 return nullptr;
2169 }
2170
2171 template<typename _Key, typename _Value, typename _Alloc,
2172 typename _ExtractKey, typename _Equal,
2173 typename _Hash, typename _RangeHash, typename _Unused,
2174 typename _RehashPolicy, typename _Traits>
2175 template<typename _Kt>
2176 auto
2177 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2178 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2179 _M_find_before_node_tr(size_type __bkt, const _Kt& __k,
2180 __hash_code __code) const
2181 -> __node_base_ptr
2182 {
2183 __node_base_ptr __prev_p = _M_buckets[__bkt];
2184 if (!__prev_p)
2185 return nullptr;
2186
2187 for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
2188 __p = __p->_M_next())
2189 {
2190 if (this->_M_equals_tr(__k, __code, *__p))
2191 return __prev_p;
2192
2193 if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
2194 break;
2195 __prev_p = __p;
2196 }
2197
2198 return nullptr;
2199 }
2200
2201 template<typename _Key, typename _Value, typename _Alloc,
2202 typename _ExtractKey, typename _Equal,
2203 typename _Hash, typename _RangeHash, typename _Unused,
2204 typename _RehashPolicy, typename _Traits>
2205 auto
2206 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2207 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2208 _M_locate(const key_type& __k) const
2209 -> __location_type
2210 {
2211 __location_type __loc;
2212 const auto __size = size();
2213
2214 if (__size <= __small_size_threshold())
2215 {
2216 __loc._M_before = pointer_traits<__node_base_ptr>::
2217 pointer_to(const_cast<__node_base&>(_M_before_begin));
2218 while (__loc._M_before->_M_nxt)
2219 {
2220 if (this->_M_key_equals(__k, *__loc._M_node()))
2221 return __loc;
2222 __loc._M_before = __loc._M_before->_M_nxt;
2223 }
2224 __loc._M_before = nullptr; // Didn't find it.
2225 }
2226
2227 __loc._M_hash_code = this->_M_hash_code(__k);
2228 __loc._M_bucket_index = _M_bucket_index(__loc._M_hash_code);
2229
2230 if (__size > __small_size_threshold())
2231 __loc._M_before = _M_find_before_node(__loc._M_bucket_index, __k,
2232 __loc._M_hash_code);
2233
2234 return __loc;
2235 }
2236
2237 template<typename _Key, typename _Value, typename _Alloc,
2238 typename _ExtractKey, typename _Equal,
2239 typename _Hash, typename _RangeHash, typename _Unused,
2240 typename _RehashPolicy, typename _Traits>
2241 auto
2242 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2243 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2244 _M_get_previous_node(size_type __bkt, __node_ptr __n)
2245 -> __node_base_ptr
2246 {
2247 __node_base_ptr __prev_n = _M_buckets[__bkt];
2248 while (__prev_n->_M_nxt != __n)
2249 __prev_n = __prev_n->_M_nxt;
2250 return __prev_n;
2251 }
2252
2253#pragma GCC diagnostic push
2254#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2255 template<typename _Key, typename _Value, typename _Alloc,
2256 typename _ExtractKey, typename _Equal,
2257 typename _Hash, typename _RangeHash, typename _Unused,
2258 typename _RehashPolicy, typename _Traits>
2259 template<typename... _Args>
2260 auto
2261 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2262 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2263 _M_emplace_uniq(_Args&&... __args)
2264 -> pair<iterator, bool>
2265 {
2266 const key_type* __kp = nullptr;
2267
2268 if constexpr (sizeof...(_Args) == 1)
2269 {
2270 if constexpr (__is_key_type<_Args...>)
2271 {
2272 const auto& __key = _ExtractKey{}(__args...);
2273 __kp = std::__addressof(__key);
2274 }
2275 }
2276 else if constexpr (sizeof...(_Args) == 2)
2277 {
2278 pair<const _Args&...> __refs(__args...);
2279 if constexpr (__is_key_type<pair<_Args...>>)
2280 {
2281 const auto& __key = _ExtractKey{}(__refs);
2282 __kp = std::__addressof(__key);
2283 }
2284 }
2285
2286 _Scoped_node __node { __node_ptr(), this }; // Do not create node yet.
2287 __hash_code __code = 0;
2288 size_type __bkt = 0;
2289
2290 if (__kp == nullptr)
2291 {
2292 // Didn't extract a key from the args, so build the node.
2293 __node._M_node
2294 = this->_M_allocate_node(std::forward<_Args>(__args)...);
2295 const key_type& __key = _ExtractKey{}(__node._M_node->_M_v());
2296 __kp = std::__addressof(__key);
2297 }
2298
2299 if (auto __loc = _M_locate(*__kp))
2300 // There is already an equivalent node, no insertion.
2301 return { iterator(__loc), false };
2302 else
2303 {
2304 __code = __loc._M_hash_code;
2305 __bkt = __loc._M_bucket_index;
2306 }
2307
2308 if (!__node._M_node)
2309 __node._M_node
2310 = this->_M_allocate_node(std::forward<_Args>(__args)...);
2311
2312 // Insert the node
2313 auto __pos = _M_insert_unique_node(__bkt, __code, __node._M_node);
2314 __node._M_node = nullptr;
2315 return { __pos, true };
2316 }
2317#pragma GCC diagnostic pop
2318
2319 template<typename _Key, typename _Value, typename _Alloc,
2320 typename _ExtractKey, typename _Equal,
2321 typename _Hash, typename _RangeHash, typename _Unused,
2322 typename _RehashPolicy, typename _Traits>
2323 template<typename... _Args>
2324 auto
2325 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2326 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2327 _M_emplace_multi(const_iterator __hint, _Args&&... __args)
2328 -> iterator
2329 {
2330 // First build the node to get its hash code.
2331 _Scoped_node __node { this, std::forward<_Args>(__args)... };
2332 const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
2333
2334 auto __res = this->_M_compute_hash_code(__hint._M_cur, __k);
2335 auto __pos
2336 = _M_insert_multi_node(__res.first, __res.second, __node._M_node);
2337 __node._M_node = nullptr;
2338 return __pos;
2339 }
2340
2341 template<typename _Key, typename _Value, typename _Alloc,
2342 typename _ExtractKey, typename _Equal,
2343 typename _Hash, typename _RangeHash, typename _Unused,
2344 typename _RehashPolicy, typename _Traits>
2345 template<typename _InputIterator>
2346 void
2347 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2348 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2349 _M_insert_range_multi(_InputIterator __first, _InputIterator __last)
2350 {
2351 using __pair_type = std::pair<bool, std::size_t>;
2352
2353 size_type __n_elt = __detail::__distance_fw(__first, __last);
2354 if (__n_elt == 0)
2355 return;
2356
2357 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2358 __pair_type __do_rehash
2359 = _M_rehash_policy._M_need_rehash(_M_bucket_count,
2360 _M_element_count,
2361 __n_elt);
2362
2363 if (__do_rehash.first)
2364 _M_rehash(__do_rehash.second, false_type{});
2365
2366 __rehash_guard._M_guarded_obj = nullptr;
2367 for (; __first != __last; ++__first)
2368 _M_emplace_multi(cend(), *__first);
2369 }
2370
2371 template<typename _Key, typename _Value, typename _Alloc,
2372 typename _ExtractKey, typename _Equal,
2373 typename _Hash, typename _RangeHash, typename _Unused,
2374 typename _RehashPolicy, typename _Traits>
2375 auto
2376 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2377 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2378 _M_compute_hash_code(__node_ptr __hint, const key_type& __k) const
2379 -> pair<__node_ptr, __hash_code>
2380 {
2381 if (size() <= __small_size_threshold())
2382 {
2383 if (__hint)
2384 {
2385 for (auto __it = __hint; __it; __it = __it->_M_next())
2386 if (this->_M_key_equals(__k, *__it))
2387 return { __it, this->_M_hash_code(*__it) };
2388 }
2389
2390 for (auto __it = _M_begin(); __it != __hint; __it = __it->_M_next())
2391 if (this->_M_key_equals(__k, *__it))
2392 return { __it, this->_M_hash_code(*__it) };
2393
2394 __hint = nullptr;
2395 }
2396
2397 return { __hint, this->_M_hash_code(__k) };
2398 }
2399
2400 template<typename _Key, typename _Value, typename _Alloc,
2401 typename _ExtractKey, typename _Equal,
2402 typename _Hash, typename _RangeHash, typename _Unused,
2403 typename _RehashPolicy, typename _Traits>
2404 auto
2405 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2406 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2407 _M_insert_unique_node(size_type __bkt, __hash_code __code,
2408 __node_ptr __node, size_type __n_elt)
2409 -> iterator
2410 {
2411 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2413 = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count,
2414 __n_elt);
2415
2416 if (__do_rehash.first)
2417 {
2418 _M_rehash(__do_rehash.second, true_type{});
2419 __bkt = _M_bucket_index(__code);
2420 }
2421
2422 __rehash_guard._M_guarded_obj = nullptr;
2423 this->_M_store_code(*__node, __code);
2424
2425 // Always insert at the beginning of the bucket.
2426 _M_insert_bucket_begin(__bkt, __node);
2427 ++_M_element_count;
2428 return iterator(__node);
2429 }
2430
2431 template<typename _Key, typename _Value, typename _Alloc,
2432 typename _ExtractKey, typename _Equal,
2433 typename _Hash, typename _RangeHash, typename _Unused,
2434 typename _RehashPolicy, typename _Traits>
2435 auto
2436 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2437 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2438 _M_insert_multi_node(__node_ptr __hint,
2439 __hash_code __code, __node_ptr __node)
2440 -> iterator
2441 {
2442 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2444 = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
2445
2446 if (__do_rehash.first)
2447 _M_rehash(__do_rehash.second, false_type{});
2448
2449 __rehash_guard._M_guarded_obj = nullptr;
2450 this->_M_store_code(*__node, __code);
2451 const key_type& __k = _ExtractKey{}(__node->_M_v());
2452 size_type __bkt = _M_bucket_index(__code);
2453
2454 // Find the node before an equivalent one or use hint if it exists and
2455 // if it is equivalent.
2456 __node_base_ptr __prev
2457 = __builtin_expect(__hint != nullptr, false)
2458 && this->_M_equals(__k, __code, *__hint)
2459 ? __hint
2460 : _M_find_before_node(__bkt, __k, __code);
2461
2462 if (__prev)
2463 {
2464 // Insert after the node before the equivalent one.
2465 __node->_M_nxt = __prev->_M_nxt;
2466 __prev->_M_nxt = __node;
2467 if (__builtin_expect(__prev == __hint, false))
2468 // hint might be the last bucket node, in this case we need to
2469 // update next bucket.
2470 if (__node->_M_nxt
2471 && !this->_M_equals(__k, __code, *__node->_M_next()))
2472 {
2473 size_type __next_bkt = _M_bucket_index(*__node->_M_next());
2474 if (__next_bkt != __bkt)
2475 _M_buckets[__next_bkt] = __node;
2476 }
2477 }
2478 else
2479 // The inserted node has no equivalent in the hashtable. We must
2480 // insert the new node at the beginning of the bucket to preserve
2481 // equivalent elements' relative positions.
2482 _M_insert_bucket_begin(__bkt, __node);
2483 ++_M_element_count;
2484 return iterator(__node);
2485 }
2486
2487 template<typename _Key, typename _Value, typename _Alloc,
2488 typename _ExtractKey, typename _Equal,
2489 typename _Hash, typename _RangeHash, typename _Unused,
2490 typename _RehashPolicy, typename _Traits>
2491 auto
2492 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2493 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2494 erase(const_iterator __it)
2495 -> iterator
2496 {
2497 __node_ptr __n = __it._M_cur;
2498 std::size_t __bkt = _M_bucket_index(*__n);
2499
2500 // Look for previous node to unlink it from the erased one, this
2501 // is why we need buckets to contain the before begin to make
2502 // this search fast.
2503 __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2504 return _M_erase(__bkt, __prev_n, __n);
2505 }
2506
2507 template<typename _Key, typename _Value, typename _Alloc,
2508 typename _ExtractKey, typename _Equal,
2509 typename _Hash, typename _RangeHash, typename _Unused,
2510 typename _RehashPolicy, typename _Traits>
2511 auto
2512 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2513 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2514 _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n)
2515 -> iterator
2516 {
2517 if (__prev_n == _M_buckets[__bkt])
2518 _M_remove_bucket_begin(__bkt, __n->_M_next(),
2519 __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
2520 else if (__n->_M_nxt)
2521 {
2522 size_type __next_bkt = _M_bucket_index(*__n->_M_next());
2523 if (__next_bkt != __bkt)
2524 _M_buckets[__next_bkt] = __prev_n;
2525 }
2526
2527 __prev_n->_M_nxt = __n->_M_nxt;
2528 iterator __result(__n->_M_next());
2529 this->_M_deallocate_node(__n);
2530 --_M_element_count;
2531
2532 return __result;
2533 }
2534
2535#pragma GCC diagnostic push
2536#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2537 template<typename _Key, typename _Value, typename _Alloc,
2538 typename _ExtractKey, typename _Equal,
2539 typename _Hash, typename _RangeHash, typename _Unused,
2540 typename _RehashPolicy, typename _Traits>
2541 auto
2542 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2543 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2544 erase(const key_type& __k)
2545 -> size_type
2546 {
2547 auto __loc = _M_locate(__k);
2548 if (!__loc)
2549 return 0;
2550
2551 __node_base_ptr __prev_n = __loc._M_before;
2552 __node_ptr __n = __loc._M_node();
2553 auto __bkt = __loc._M_bucket_index;
2554 if (__bkt == size_type(-1))
2555 __bkt = _M_bucket_index(*__n);
2556
2557 if constexpr (__unique_keys::value)
2558 {
2559 _M_erase(__bkt, __prev_n, __n);
2560 return 1;
2561 }
2562 else
2563 {
2564 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2565 // 526. Is it undefined if a function in the standard changes
2566 // in parameters?
2567 // We use one loop to find all matching nodes and another to
2568 // deallocate them so that the key stays valid during the first loop.
2569 // It might be invalidated indirectly when destroying nodes.
2570 __node_ptr __n_last = __n->_M_next();
2571 while (__n_last && this->_M_node_equals(*__n, *__n_last))
2572 __n_last = __n_last->_M_next();
2573
2574 std::size_t __n_last_bkt
2575 = __n_last ? _M_bucket_index(*__n_last) : __bkt;
2576
2577 // Deallocate nodes.
2578 size_type __result = 0;
2579 do
2580 {
2581 __node_ptr __p = __n->_M_next();
2582 this->_M_deallocate_node(__n);
2583 __n = __p;
2584 ++__result;
2585 }
2586 while (__n != __n_last);
2587
2588 _M_element_count -= __result;
2589 if (__prev_n == _M_buckets[__bkt])
2590 _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
2591 else if (__n_last_bkt != __bkt)
2592 _M_buckets[__n_last_bkt] = __prev_n;
2593 __prev_n->_M_nxt = __n_last;
2594 return __result;
2595 }
2596 }
2597#pragma GCC diagnostic pop
2598
2599 template<typename _Key, typename _Value, typename _Alloc,
2600 typename _ExtractKey, typename _Equal,
2601 typename _Hash, typename _RangeHash, typename _Unused,
2602 typename _RehashPolicy, typename _Traits>
2603 auto
2604 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2605 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2606 erase(const_iterator __first, const_iterator __last)
2607 -> iterator
2608 {
2609 __node_ptr __n = __first._M_cur;
2610 __node_ptr __last_n = __last._M_cur;
2611 if (__n == __last_n)
2612 return iterator(__n);
2613
2614 std::size_t __bkt = _M_bucket_index(*__n);
2615
2616 __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2617 bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
2618 std::size_t __n_bkt = __bkt;
2619 for (;;)
2620 {
2621 do
2622 {
2623 __node_ptr __tmp = __n;
2624 __n = __n->_M_next();
2625 this->_M_deallocate_node(__tmp);
2626 --_M_element_count;
2627 if (!__n)
2628 break;
2629 __n_bkt = _M_bucket_index(*__n);
2630 }
2631 while (__n != __last_n && __n_bkt == __bkt);
2632 if (__is_bucket_begin)
2633 _M_remove_bucket_begin(__bkt, __n, __n_bkt);
2634 if (__n == __last_n)
2635 break;
2636 __is_bucket_begin = true;
2637 __bkt = __n_bkt;
2638 }
2639
2640 if (__n && (__n_bkt != __bkt || __is_bucket_begin))
2641 _M_buckets[__n_bkt] = __prev_n;
2642 __prev_n->_M_nxt = __n;
2643 return iterator(__n);
2644 }
2645
2646 template<typename _Key, typename _Value, typename _Alloc,
2647 typename _ExtractKey, typename _Equal,
2648 typename _Hash, typename _RangeHash, typename _Unused,
2649 typename _RehashPolicy, typename _Traits>
2650 void
2651 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2652 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2653 clear() noexcept
2654 {
2655 this->_M_deallocate_nodes(_M_begin());
2656 std::fill_n(_M_buckets, _M_bucket_count, nullptr);
2657 _M_element_count = 0;
2658 _M_before_begin._M_nxt = nullptr;
2659 }
2660
2661 template<typename _Key, typename _Value, typename _Alloc,
2662 typename _ExtractKey, typename _Equal,
2663 typename _Hash, typename _RangeHash, typename _Unused,
2664 typename _RehashPolicy, typename _Traits>
2665 void
2666 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2667 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2668 rehash(size_type __bkt_count)
2669 {
2670 __rehash_guard_t __rehash_guard(_M_rehash_policy);
2671 __bkt_count
2672 = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
2673 __bkt_count);
2674 __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count);
2675
2676 if (__bkt_count != _M_bucket_count)
2677 {
2678 _M_rehash(__bkt_count, __unique_keys{});
2679 __rehash_guard._M_guarded_obj = nullptr;
2680 }
2681 }
2682
2683 // Rehash when there is no equivalent elements.
2684 template<typename _Key, typename _Value, typename _Alloc,
2685 typename _ExtractKey, typename _Equal,
2686 typename _Hash, typename _RangeHash, typename _Unused,
2687 typename _RehashPolicy, typename _Traits>
2688 void
2689 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2690 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2691 _M_rehash(size_type __bkt_count, true_type /* __uks */)
2692 {
2693 __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2694 __node_ptr __p = _M_begin();
2695 _M_before_begin._M_nxt = nullptr;
2696 std::size_t __bbegin_bkt = 0;
2697 while (__p)
2698 {
2699 __node_ptr __next = __p->_M_next();
2700 std::size_t __bkt
2701 = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2702 if (!__new_buckets[__bkt])
2703 {
2704 __p->_M_nxt = _M_before_begin._M_nxt;
2705 _M_before_begin._M_nxt = __p;
2706 __new_buckets[__bkt] = &_M_before_begin;
2707 if (__p->_M_nxt)
2708 __new_buckets[__bbegin_bkt] = __p;
2709 __bbegin_bkt = __bkt;
2710 }
2711 else
2712 {
2713 __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2714 __new_buckets[__bkt]->_M_nxt = __p;
2715 }
2716
2717 __p = __next;
2718 }
2719
2720 _M_deallocate_buckets();
2721 _M_bucket_count = __bkt_count;
2722 _M_buckets = __new_buckets;
2723 }
2724
2725 // Rehash when there can be equivalent elements, preserve their relative
2726 // order.
2727 template<typename _Key, typename _Value, typename _Alloc,
2728 typename _ExtractKey, typename _Equal,
2729 typename _Hash, typename _RangeHash, typename _Unused,
2730 typename _RehashPolicy, typename _Traits>
2731 void
2732 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2733 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2734 _M_rehash(size_type __bkt_count, false_type /* __uks */)
2735 {
2736 __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2737 __node_ptr __p = _M_begin();
2738 _M_before_begin._M_nxt = nullptr;
2739 std::size_t __bbegin_bkt = 0;
2740 std::size_t __prev_bkt = 0;
2741 __node_ptr __prev_p = nullptr;
2742 bool __check_bucket = false;
2743
2744 while (__p)
2745 {
2746 __node_ptr __next = __p->_M_next();
2747 std::size_t __bkt
2748 = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2749
2750 if (__prev_p && __prev_bkt == __bkt)
2751 {
2752 // Previous insert was already in this bucket, we insert after
2753 // the previously inserted one to preserve equivalent elements
2754 // relative order.
2755 __p->_M_nxt = __prev_p->_M_nxt;
2756 __prev_p->_M_nxt = __p;
2757
2758 // Inserting after a node in a bucket require to check that we
2759 // haven't change the bucket last node, in this case next
2760 // bucket containing its before begin node must be updated. We
2761 // schedule a check as soon as we move out of the sequence of
2762 // equivalent nodes to limit the number of checks.
2763 __check_bucket = true;
2764 }
2765 else
2766 {
2767 if (__check_bucket)
2768 {
2769 // Check if we shall update the next bucket because of
2770 // insertions into __prev_bkt bucket.
2771 if (__prev_p->_M_nxt)
2772 {
2773 std::size_t __next_bkt
2774 = __hash_code_base::_M_bucket_index(
2775 *__prev_p->_M_next(), __bkt_count);
2776 if (__next_bkt != __prev_bkt)
2777 __new_buckets[__next_bkt] = __prev_p;
2778 }
2779 __check_bucket = false;
2780 }
2781
2782 if (!__new_buckets[__bkt])
2783 {
2784 __p->_M_nxt = _M_before_begin._M_nxt;
2785 _M_before_begin._M_nxt = __p;
2786 __new_buckets[__bkt] = &_M_before_begin;
2787 if (__p->_M_nxt)
2788 __new_buckets[__bbegin_bkt] = __p;
2789 __bbegin_bkt = __bkt;
2790 }
2791 else
2792 {
2793 __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2794 __new_buckets[__bkt]->_M_nxt = __p;
2795 }
2796 }
2797 __prev_p = __p;
2798 __prev_bkt = __bkt;
2799 __p = __next;
2800 }
2801
2802 if (__check_bucket && __prev_p->_M_nxt)
2803 {
2804 std::size_t __next_bkt
2805 = __hash_code_base::_M_bucket_index(*__prev_p->_M_next(),
2806 __bkt_count);
2807 if (__next_bkt != __prev_bkt)
2808 __new_buckets[__next_bkt] = __prev_p;
2809 }
2810
2811 _M_deallocate_buckets();
2812 _M_bucket_count = __bkt_count;
2813 _M_buckets = __new_buckets;
2814 }
2815
2816#pragma GCC diagnostic push
2817#pragma GCC diagnostic ignored "-Wc++17-extensions" // if constexpr
2818
2819 // This is for implementing equality comparison for unordered containers,
2820 // per N3068, by John Lakos and Pablo Halpern.
2821 // Algorithmically, we follow closely the reference implementations therein.
2822 template<typename _Key, typename _Value, typename _Alloc,
2823 typename _ExtractKey, typename _Equal,
2824 typename _Hash, typename _RangeHash, typename _Unused,
2825 typename _RehashPolicy, typename _Traits>
2826 bool
2827 _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2828 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2829 _M_equal(const _Hashtable& __other) const
2830 {
2831 if (size() != __other.size())
2832 return false;
2833
2834 if constexpr (__unique_keys::value)
2835 for (auto __x_n = _M_begin(); __x_n; __x_n = __x_n->_M_next())
2836 {
2837 std::size_t __ybkt = __other._M_bucket_index(*__x_n);
2838 auto __prev_n = __other._M_buckets[__ybkt];
2839 if (!__prev_n)
2840 return false;
2841
2842 for (__node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);;
2843 __n = __n->_M_next())
2844 {
2845 if (__n->_M_v() == __x_n->_M_v())
2846 break;
2847
2848 if (!__n->_M_nxt
2849 || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
2850 return false;
2851 }
2852 }
2853 else // non-unique keys
2854 for (auto __x_n = _M_begin(); __x_n;)
2855 {
2856 std::size_t __x_count = 1;
2857 auto __x_n_end = __x_n->_M_next();
2858 for (; __x_n_end
2859 && key_eq()(_ExtractKey{}(__x_n->_M_v()),
2860 _ExtractKey{}(__x_n_end->_M_v()));
2861 __x_n_end = __x_n_end->_M_next())
2862 ++__x_count;
2863
2864 std::size_t __ybkt = __other._M_bucket_index(*__x_n);
2865 auto __y_prev_n = __other._M_buckets[__ybkt];
2866 if (!__y_prev_n)
2867 return false;
2868
2869 __node_ptr __y_n = static_cast<__node_ptr>(__y_prev_n->_M_nxt);
2870 for (;;)
2871 {
2872 if (key_eq()(_ExtractKey{}(__y_n->_M_v()),
2873 _ExtractKey{}(__x_n->_M_v())))
2874 break;
2875
2876 auto __y_ref_n = __y_n;
2877 for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
2878 if (!__other._M_node_equals(*__y_ref_n, *__y_n))
2879 break;
2880
2881 if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
2882 return false;
2883 }
2884
2885 auto __y_n_end = __y_n;
2886 for (; __y_n_end; __y_n_end = __y_n_end->_M_next())
2887 if (--__x_count == 0)
2888 break;
2889
2890 if (__x_count != 0)
2891 return false;
2892
2893 const_iterator __itx(__x_n), __itx_end(__x_n_end);
2894 const_iterator __ity(__y_n);
2895 if (!std::is_permutation(__itx, __itx_end, __ity))
2896 return false;
2897
2898 __x_n = __x_n_end;
2899 }
2900
2901 return true;
2902 }
2903#pragma GCC diagnostic pop
2904
2905#if __cplusplus > 201402L
2906 template<typename, typename, typename> class _Hash_merge_helper { };
2907#endif // C++17
2908
2909#if __cpp_deduction_guides >= 201606
2910 // Used to constrain deduction guides
2911 template<typename _Hash>
2912 using _RequireNotAllocatorOrIntegral
2913 = __enable_if_t<!__or_<is_integral<_Hash>, __is_allocator<_Hash>>::value>;
2914#endif
2915
2916/// @endcond
2917_GLIBCXX_END_NAMESPACE_VERSION
2918} // namespace std
2919
2920#pragma GCC diagnostic pop
2921
2922#endif // _HASHTABLE_H
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
Definition type_traits:116
constexpr tuple< _Elements &&... > forward_as_tuple(_Elements &&... __args) noexcept
Create a tuple of lvalue or rvalue references to the arguments.
Definition tuple:2678
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition move.h:127
constexpr piecewise_construct_t piecewise_construct
Tag for piecewise construction of std::pair objects.
Definition stl_pair.h:82
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition move.h:51
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition move.h:70
_Tp * end(valarray< _Tp > &__va) noexcept
Return an iterator pointing to one past the last element of the valarray.
Definition valarray:1251
_Tp * begin(valarray< _Tp > &__va) noexcept
Return an iterator pointing to the first element of the valarray.
Definition valarray:1229
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
ISO C++ entities toplevel namespace is std.
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
constexpr auto cend(const _Container &__cont) noexcept(noexcept(std::end(__cont))) -> decltype(std::end(__cont))
Return an iterator pointing to one past the last element of the const container.
constexpr auto empty(const _Container &__cont) noexcept(noexcept(__cont.empty())) -> decltype(__cont.empty())
Return whether a container is empty.
constexpr auto size(const _Container &__cont) noexcept(noexcept(__cont.size())) -> decltype(__cont.size())
Return the size of a container.
constexpr auto cbegin(const _Container &__cont) noexcept(noexcept(std::begin(__cont))) -> decltype(std::begin(__cont))
Return an iterator pointing to the first element of the const container.
Struct holding two objects of arbitrary type.
Definition stl_pair.h:286
_T1 first
The first member.
Definition stl_pair.h:290
_T2 second
The second member.
Definition stl_pair.h:291