libstdc++
bits/hashtable.h
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00001 // hashtable.h header -*- C++ -*-
00002 
00003 // Copyright (C) 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /** @file bits/hashtable.h
00026  *  This is an internal header file, included by other library headers.
00027  *  Do not attempt to use it directly. @headername{unordered_map, unordered_set}
00028  */
00029 
00030 #ifndef _HASHTABLE_H
00031 #define _HASHTABLE_H 1
00032 
00033 #pragma GCC system_header
00034 
00035 #include <bits/hashtable_policy.h>
00036 
00037 namespace std _GLIBCXX_VISIBILITY(default)
00038 {
00039 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00040 
00041   // Class template _Hashtable, class definition.
00042 
00043   // Meaning of class template _Hashtable's template parameters
00044 
00045   // _Key and _Value: arbitrary CopyConstructible types.
00046 
00047   // _Allocator: an allocator type ([lib.allocator.requirements]) whose
00048   // value type is Value.  As a conforming extension, we allow for
00049   // value type != Value.
00050 
00051   // _ExtractKey: function object that takes an object of type Value
00052   // and returns a value of type _Key.
00053 
00054   // _Equal: function object that takes two objects of type k and returns
00055   // a bool-like value that is true if the two objects are considered equal.
00056 
00057   // _H1: the hash function.  A unary function object with argument type
00058   // Key and result type size_t.  Return values should be distributed
00059   // over the entire range [0, numeric_limits<size_t>:::max()].
00060 
00061   // _H2: the range-hashing function (in the terminology of Tavori and
00062   // Dreizin).  A binary function object whose argument types and result
00063   // type are all size_t.  Given arguments r and N, the return value is
00064   // in the range [0, N).
00065 
00066   // _Hash: the ranged hash function (Tavori and Dreizin). A binary function
00067   // whose argument types are _Key and size_t and whose result type is
00068   // size_t.  Given arguments k and N, the return value is in the range
00069   // [0, N).  Default: hash(k, N) = h2(h1(k), N).  If _Hash is anything other
00070   // than the default, _H1 and _H2 are ignored.
00071 
00072   // _RehashPolicy: Policy class with three members, all of which govern
00073   // the bucket count. _M_next_bkt(n) returns a bucket count no smaller
00074   // than n.  _M_bkt_for_elements(n) returns a bucket count appropriate
00075   // for an element count of n.  _M_need_rehash(n_bkt, n_elt, n_ins)
00076   // determines whether, if the current bucket count is n_bkt and the
00077   // current element count is n_elt, we need to increase the bucket
00078   // count.  If so, returns make_pair(true, n), where n is the new
00079   // bucket count.  If not, returns make_pair(false, <anything>).
00080 
00081   // __cache_hash_code: bool.  true if we store the value of the hash
00082   // function along with the value.  This is a time-space tradeoff.
00083   // Storing it may improve lookup speed by reducing the number of times
00084   // we need to call the Equal function.
00085 
00086   // __constant_iterators: bool.  true if iterator and const_iterator are
00087   // both constant iterator types.  This is true for unordered_set and
00088   // unordered_multiset, false for unordered_map and unordered_multimap.
00089 
00090   // __unique_keys: bool.  true if the return value of _Hashtable::count(k)
00091   // is always at most one, false if it may be an arbitrary number.  This
00092   // true for unordered_set and unordered_map, false for unordered_multiset
00093   // and unordered_multimap.
00094   /**
00095    * Here's _Hashtable data structure, each _Hashtable has:
00096    * - _Bucket[]       _M_buckets
00097    * - _Hash_node_base _M_before_begin
00098    * - size_type       _M_bucket_count
00099    * - size_type       _M_element_count
00100    *
00101    * with _Bucket being _Hash_node* and _Hash_node constaining:
00102    * - _Hash_node*   _M_next
00103    * - Tp            _M_value
00104    * - size_t        _M_code if cache_hash_code is true
00105    *
00106    * In terms of Standard containers the hastable is like the aggregation of:
00107    * - std::forward_list<_Node> containing the elements
00108    * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
00109    *
00110    * The non-empty buckets contain the node before the first bucket node. This
00111    * design allow to implement something like a std::forward_list::insert_after
00112    * on container insertion and std::forward_list::erase_after on container
00113    * erase calls. _M_before_begin is equivalent to
00114    * std::foward_list::before_begin. Empty buckets are containing nullptr.
00115    * Note that one of the non-empty bucket contains &_M_before_begin which is
00116    * not a derefenrenceable node so the node pointers in buckets shall never be
00117    * derefenrenced, only its next node can be.
00118    * 
00119    * Walk through a bucket nodes require a check on the hash code to see if the
00120    * node is still in the bucket. Such a design impose a quite efficient hash
00121    * functor and is one of the reasons it is highly advise to set
00122    * __cache_hash_code to true.
00123    *
00124    * The container iterators are simply built from nodes. This way incrementing
00125    * the iterator is perfectly efficient independent of how many empty buckets
00126    * there are in the container.
00127    *
00128    * On insert we compute element hash code and thanks to it find the bucket
00129    * index. If the element must be inserted on an empty bucket we add it at the
00130    * beginning of the singly linked list and make the bucket point to
00131    * _M_before_begin. The bucket that used to point to _M_before_begin, if any,
00132    * is updated to point to its new before begin node.
00133    *
00134    * On erase, the simple iterator design impose to use the hash functor to get
00135    * the index of the bucket to update. For this reason, when __cache_hash_code
00136    * is set to false, there is a static assertion that the hash functor cannot
00137    * throw.
00138    */
00139 
00140   template<typename _Key, typename _Value, typename _Allocator,
00141        typename _ExtractKey, typename _Equal,
00142        typename _H1, typename _H2, typename _Hash,
00143        typename _RehashPolicy,
00144        bool __cache_hash_code,
00145        bool __constant_iterators,
00146        bool __unique_keys>
00147     class _Hashtable
00148     : public __detail::_Rehash_base<_RehashPolicy,
00149                     _Hashtable<_Key, _Value, _Allocator,
00150                            _ExtractKey,
00151                            _Equal, _H1, _H2, _Hash,
00152                            _RehashPolicy,
00153                            __cache_hash_code,
00154                            __constant_iterators,
00155                            __unique_keys> >,
00156       public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
00157                        _H1, _H2, _Hash, __cache_hash_code>,
00158       public __detail::_Map_base<_Key, _Value, _ExtractKey, __unique_keys,
00159                  _Hashtable<_Key, _Value, _Allocator,
00160                         _ExtractKey,
00161                         _Equal, _H1, _H2, _Hash,
00162                         _RehashPolicy,
00163                         __cache_hash_code,
00164                         __constant_iterators,
00165                         __unique_keys> >,
00166       public __detail::_Equality_base<_ExtractKey, __unique_keys,
00167                       _Hashtable<_Key, _Value, _Allocator,
00168                          _ExtractKey,
00169                          _Equal, _H1, _H2, _Hash,
00170                          _RehashPolicy,
00171                          __cache_hash_code,
00172                          __constant_iterators,
00173                          __unique_keys> >
00174     {
00175       template<typename _Cond>
00176     using __if_hash_code_cached
00177       = __or_<__not_<integral_constant<bool, __cache_hash_code>>, _Cond>;
00178 
00179       template<typename _Cond>
00180     using __if_hash_code_not_cached
00181       = __or_<integral_constant<bool, __cache_hash_code>, _Cond>;
00182 
00183       // When hash codes are not cached the hash functor shall not throw
00184       // because it is used in methods (erase, swap...) that shall not throw.
00185       static_assert(__if_hash_code_not_cached<__detail::__is_noexcept_hash<_Key,
00186                                 _H1>>::value,
00187             "Cache the hash code or qualify your hash functor with noexcept");
00188 
00189       // Following two static assertions are necessary to guarantee that
00190       // swapping two hashtable instances won't invalidate associated local
00191       // iterators.
00192 
00193       // When hash codes are cached local iterator only uses H2 which must then
00194       // be empty.
00195       static_assert(__if_hash_code_cached<is_empty<_H2>>::value,
00196         "Functor used to map hash code to bucket index must be empty");
00197 
00198       typedef __detail::_Hash_code_base<_Key, _Value, _ExtractKey,
00199                     _H1, _H2, _Hash,
00200                         __cache_hash_code> _HCBase;
00201 
00202       // When hash codes are not cached local iterator is going to use _HCBase
00203       // above to compute node bucket index so it has to be empty.
00204       static_assert(__if_hash_code_not_cached<is_empty<_HCBase>>::value,
00205         "Cache the hash code or make functors involved in hash code"
00206         " and bucket index computation empty");
00207 
00208     public:
00209       typedef _Allocator                                  allocator_type;
00210       typedef _Value                                      value_type;
00211       typedef _Key                                        key_type;
00212       typedef _Equal                                      key_equal;
00213       // mapped_type, if present, comes from _Map_base.
00214       // hasher, if present, comes from _Hash_code_base.
00215       typedef typename _Allocator::pointer                pointer;
00216       typedef typename _Allocator::const_pointer          const_pointer;
00217       typedef typename _Allocator::reference              reference;
00218       typedef typename _Allocator::const_reference        const_reference;
00219 
00220       typedef std::size_t                                 size_type;
00221       typedef std::ptrdiff_t                              difference_type;
00222       typedef __detail::_Local_iterator<key_type, value_type, _ExtractKey,
00223                     _H1, _H2, _Hash,
00224                     __constant_iterators,
00225                     __cache_hash_code>
00226                               local_iterator;
00227       typedef __detail::_Local_const_iterator<key_type, value_type, _ExtractKey,
00228                           _H1, _H2, _Hash,
00229                           __constant_iterators,
00230                           __cache_hash_code>
00231                               const_local_iterator;
00232       typedef __detail::_Node_iterator<value_type, __constant_iterators,
00233                        __cache_hash_code>
00234                               iterator;
00235       typedef __detail::_Node_const_iterator<value_type,
00236                          __constant_iterators,
00237                          __cache_hash_code>
00238                               const_iterator;
00239 
00240       template<typename _Key2, typename _Value2, typename _Ex2, bool __unique2,
00241            typename _Hashtable2>
00242     friend struct __detail::_Map_base;
00243 
00244     private:
00245       typedef typename _RehashPolicy::_State _RehashPolicyState;
00246       typedef __detail::_Hash_node<_Value, __cache_hash_code> _Node;
00247       typedef typename _Allocator::template rebind<_Node>::other
00248                             _Node_allocator_type;
00249       typedef __detail::_Hash_node_base _BaseNode;
00250       typedef _BaseNode* _Bucket;
00251       typedef typename _Allocator::template rebind<_Bucket>::other
00252                             _Bucket_allocator_type;
00253 
00254       typedef typename _Allocator::template rebind<_Value>::other
00255                             _Value_allocator_type;
00256 
00257       _Node_allocator_type  _M_node_allocator;
00258       _Bucket*          _M_buckets;
00259       size_type         _M_bucket_count;
00260       _BaseNode         _M_before_begin;
00261       size_type         _M_element_count;
00262       _RehashPolicy     _M_rehash_policy;
00263 
00264       template<typename... _Args>
00265     _Node*
00266     _M_allocate_node(_Args&&... __args);
00267 
00268       void
00269       _M_deallocate_node(_Node* __n);
00270 
00271       // Deallocate the linked list of nodes pointed to by __n
00272       void
00273       _M_deallocate_nodes(_Node* __n);
00274 
00275       _Bucket*
00276       _M_allocate_buckets(size_type __n);
00277 
00278       void
00279       _M_deallocate_buckets(_Bucket*, size_type __n);
00280 
00281       // Gets bucket begin, deals with the fact that non-empty buckets contain
00282       // their before begin node.
00283       _Node*
00284       _M_bucket_begin(size_type __bkt) const;
00285 
00286       _Node*
00287       _M_begin() const
00288       { return static_cast<_Node*>(_M_before_begin._M_nxt); }
00289 
00290     public:
00291       // Constructor, destructor, assignment, swap
00292       _Hashtable(size_type __bucket_hint,
00293          const _H1&, const _H2&, const _Hash&,
00294          const _Equal&, const _ExtractKey&,
00295          const allocator_type&);
00296 
00297       template<typename _InputIterator>
00298     _Hashtable(_InputIterator __first, _InputIterator __last,
00299            size_type __bucket_hint,
00300            const _H1&, const _H2&, const _Hash&,
00301            const _Equal&, const _ExtractKey&,
00302            const allocator_type&);
00303 
00304       _Hashtable(const _Hashtable&);
00305 
00306       _Hashtable(_Hashtable&&);
00307 
00308       _Hashtable&
00309       operator=(const _Hashtable& __ht)
00310       {
00311     _Hashtable __tmp(__ht);
00312     this->swap(__tmp);
00313     return *this;
00314       }
00315 
00316       _Hashtable&
00317       operator=(_Hashtable&& __ht)
00318       {
00319     // NB: DR 1204.
00320     // NB: DR 675.
00321     this->clear();
00322     this->swap(__ht);
00323     return *this;
00324       }
00325 
00326       ~_Hashtable() noexcept;
00327 
00328       void swap(_Hashtable&);
00329 
00330       // Basic container operations
00331       iterator
00332       begin() noexcept
00333       { return iterator(_M_begin()); }
00334 
00335       const_iterator
00336       begin() const noexcept
00337       { return const_iterator(_M_begin()); }
00338 
00339       iterator
00340       end() noexcept
00341       { return iterator(nullptr); }
00342 
00343       const_iterator
00344       end() const noexcept
00345       { return const_iterator(nullptr); }
00346 
00347       const_iterator
00348       cbegin() const noexcept
00349       { return const_iterator(_M_begin()); }
00350 
00351       const_iterator
00352       cend() const noexcept
00353       { return const_iterator(nullptr); }
00354 
00355       size_type
00356       size() const noexcept
00357       { return _M_element_count; }
00358 
00359       bool
00360       empty() const noexcept
00361       { return size() == 0; }
00362 
00363       allocator_type
00364       get_allocator() const noexcept
00365       { return allocator_type(_M_node_allocator); }
00366 
00367       size_type
00368       max_size() const noexcept
00369       { return _M_node_allocator.max_size(); }
00370 
00371       // Observers
00372       key_equal
00373       key_eq() const
00374       { return this->_M_eq(); }
00375 
00376       // hash_function, if present, comes from _Hash_code_base.
00377 
00378       // Bucket operations
00379       size_type
00380       bucket_count() const noexcept
00381       { return _M_bucket_count; }
00382 
00383       size_type
00384       max_bucket_count() const noexcept
00385       { return max_size(); }
00386 
00387       size_type
00388       bucket_size(size_type __n) const
00389       { return std::distance(begin(__n), end(__n)); }
00390 
00391       size_type
00392       bucket(const key_type& __k) const
00393       { return _M_bucket_index(__k, this->_M_hash_code(__k)); }
00394 
00395       local_iterator
00396       begin(size_type __n)
00397       { return local_iterator(_M_bucket_begin(__n), __n,
00398                   _M_bucket_count); }
00399 
00400       local_iterator
00401       end(size_type __n)
00402       { return local_iterator(nullptr, __n, _M_bucket_count); }
00403 
00404       const_local_iterator
00405       begin(size_type __n) const
00406       { return const_local_iterator(_M_bucket_begin(__n), __n,
00407                     _M_bucket_count); }
00408 
00409       const_local_iterator
00410       end(size_type __n) const
00411       { return const_local_iterator(nullptr, __n, _M_bucket_count); }
00412 
00413       // DR 691.
00414       const_local_iterator
00415       cbegin(size_type __n) const
00416       { return const_local_iterator(_M_bucket_begin(__n), __n,
00417                     _M_bucket_count); }
00418 
00419       const_local_iterator
00420       cend(size_type __n) const
00421       { return const_local_iterator(nullptr, __n, _M_bucket_count); }
00422 
00423       float
00424       load_factor() const noexcept
00425       {
00426     return static_cast<float>(size()) / static_cast<float>(bucket_count());
00427       }
00428 
00429       // max_load_factor, if present, comes from _Rehash_base.
00430 
00431       // Generalization of max_load_factor.  Extension, not found in TR1.  Only
00432       // useful if _RehashPolicy is something other than the default.
00433       const _RehashPolicy&
00434       __rehash_policy() const
00435       { return _M_rehash_policy; }
00436 
00437       void
00438       __rehash_policy(const _RehashPolicy&);
00439 
00440       // Lookup.
00441       iterator
00442       find(const key_type& __k);
00443 
00444       const_iterator
00445       find(const key_type& __k) const;
00446 
00447       size_type
00448       count(const key_type& __k) const;
00449 
00450       std::pair<iterator, iterator>
00451       equal_range(const key_type& __k);
00452 
00453       std::pair<const_iterator, const_iterator>
00454       equal_range(const key_type& __k) const;
00455 
00456     private:
00457       // Bucket index computation helpers.
00458       size_type
00459       _M_bucket_index(_Node* __n) const
00460       { return _HCBase::_M_bucket_index(__n, _M_bucket_count); }
00461 
00462       size_type
00463       _M_bucket_index(const key_type& __k,
00464               typename _Hashtable::_Hash_code_type __c) const
00465       { return _HCBase::_M_bucket_index(__k, __c, _M_bucket_count); }
00466 
00467       // Find and insert helper functions and types
00468       // Find the node before the one matching the criteria.
00469       _BaseNode*
00470       _M_find_before_node(size_type, const key_type&,
00471               typename _Hashtable::_Hash_code_type) const;
00472 
00473       _Node*
00474       _M_find_node(size_type __bkt, const key_type& __key,
00475            typename _Hashtable::_Hash_code_type __c) const
00476       {
00477     _BaseNode* __before_n = _M_find_before_node(__bkt, __key, __c);
00478     if (__before_n)
00479       return static_cast<_Node*>(__before_n->_M_nxt);
00480     return nullptr;
00481       }
00482 
00483       // Insert a node at the beginning of a bucket.
00484       void
00485       _M_insert_bucket_begin(size_type, _Node*);
00486 
00487       // Remove the bucket first node
00488       void
00489       _M_remove_bucket_begin(size_type __bkt, _Node* __next_n,
00490                  size_type __next_bkt);
00491 
00492       // Get the node before __n in the bucket __bkt
00493       _BaseNode*
00494       _M_get_previous_node(size_type __bkt, _BaseNode* __n);
00495 
00496       template<typename _Arg>
00497     iterator
00498     _M_insert_bucket(_Arg&&, size_type,
00499              typename _Hashtable::_Hash_code_type);
00500 
00501       typedef typename std::conditional<__unique_keys,
00502                     std::pair<iterator, bool>,
00503                     iterator>::type
00504     _Insert_Return_Type;
00505 
00506       typedef typename std::conditional<__unique_keys,
00507                     std::_Select1st<_Insert_Return_Type>,
00508                     std::_Identity<_Insert_Return_Type>
00509                    >::type
00510     _Insert_Conv_Type;
00511 
00512     protected:
00513       template<typename... _Args>
00514     std::pair<iterator, bool>
00515     _M_emplace(std::true_type, _Args&&... __args);
00516 
00517       template<typename... _Args>
00518     iterator
00519     _M_emplace(std::false_type, _Args&&... __args);
00520 
00521       template<typename _Arg>
00522     std::pair<iterator, bool>
00523     _M_insert(_Arg&&, std::true_type);
00524 
00525       template<typename _Arg>
00526     iterator
00527     _M_insert(_Arg&&, std::false_type);
00528 
00529     public:
00530       // Emplace, insert and erase
00531       template<typename... _Args>
00532     _Insert_Return_Type
00533     emplace(_Args&&... __args)
00534     { return _M_emplace(integral_constant<bool, __unique_keys>(),
00535                 std::forward<_Args>(__args)...); }
00536 
00537       template<typename... _Args>
00538     iterator
00539     emplace_hint(const_iterator, _Args&&... __args)
00540     { return _Insert_Conv_Type()(emplace(std::forward<_Args>(__args)...)); }
00541 
00542       _Insert_Return_Type
00543       insert(const value_type& __v)
00544       { return _M_insert(__v, integral_constant<bool, __unique_keys>()); }
00545 
00546       iterator
00547       insert(const_iterator, const value_type& __v)
00548       { return _Insert_Conv_Type()(insert(__v)); }
00549 
00550       template<typename _Pair, typename = typename
00551     std::enable_if<__and_<integral_constant<bool, !__constant_iterators>,
00552                   std::is_convertible<_Pair,
00553                           value_type>>::value>::type>
00554     _Insert_Return_Type
00555     insert(_Pair&& __v)
00556     { return _M_insert(std::forward<_Pair>(__v),
00557                integral_constant<bool, __unique_keys>()); }
00558 
00559       template<typename _Pair, typename = typename
00560         std::enable_if<__and_<integral_constant<bool, !__constant_iterators>,
00561                   std::is_convertible<_Pair,
00562                           value_type>>::value>::type>
00563     iterator
00564     insert(const_iterator, _Pair&& __v)
00565     { return _Insert_Conv_Type()(insert(std::forward<_Pair>(__v))); }
00566 
00567       template<typename _InputIterator>
00568     void
00569     insert(_InputIterator __first, _InputIterator __last);
00570 
00571       void
00572       insert(initializer_list<value_type> __l)
00573       { this->insert(__l.begin(), __l.end()); }
00574 
00575       iterator
00576       erase(const_iterator);
00577 
00578       // LWG 2059.
00579       iterator
00580       erase(iterator __it)
00581       { return erase(const_iterator(__it)); }
00582 
00583       size_type
00584       erase(const key_type&);
00585 
00586       iterator
00587       erase(const_iterator, const_iterator);
00588 
00589       void
00590       clear() noexcept;
00591 
00592       // Set number of buckets to be appropriate for container of n element.
00593       void rehash(size_type __n);
00594 
00595       // DR 1189.
00596       // reserve, if present, comes from _Rehash_base.
00597 
00598     private:
00599       // Helper rehash method used when keys are unique.
00600       void _M_rehash_aux(size_type __n, std::true_type);
00601 
00602       // Helper rehash method used when keys can be non-unique.
00603       void _M_rehash_aux(size_type __n, std::false_type);
00604 
00605       // Unconditionally change size of bucket array to n, restore hash policy
00606       // state to __state on exception.
00607       void _M_rehash(size_type __n, const _RehashPolicyState& __state);
00608     };
00609 
00610 
00611   // Definitions of class template _Hashtable's out-of-line member functions.
00612   template<typename _Key, typename _Value,
00613        typename _Allocator, typename _ExtractKey, typename _Equal,
00614        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00615        bool __chc, bool __cit, bool __uk>
00616     template<typename... _Args>
00617       typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00618               _H1, _H2, _Hash, _RehashPolicy,
00619               __chc, __cit, __uk>::_Node*
00620       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00621          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00622       _M_allocate_node(_Args&&... __args)
00623       {
00624     _Node* __n = _M_node_allocator.allocate(1);
00625     __try
00626       {
00627         _M_node_allocator.construct(__n, std::forward<_Args>(__args)...);
00628         return __n;
00629       }
00630     __catch(...)
00631       {
00632         _M_node_allocator.deallocate(__n, 1);
00633         __throw_exception_again;
00634       }
00635       }
00636 
00637   template<typename _Key, typename _Value,
00638        typename _Allocator, typename _ExtractKey, typename _Equal,
00639        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00640        bool __chc, bool __cit, bool __uk>
00641     void
00642     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00643            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00644     _M_deallocate_node(_Node* __n)
00645     {
00646       _M_node_allocator.destroy(__n);
00647       _M_node_allocator.deallocate(__n, 1);
00648     }
00649 
00650   template<typename _Key, typename _Value,
00651        typename _Allocator, typename _ExtractKey, typename _Equal,
00652        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00653        bool __chc, bool __cit, bool __uk>
00654     void
00655     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00656            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00657     _M_deallocate_nodes(_Node* __n)
00658     {
00659       while (__n)
00660     {
00661       _Node* __tmp = __n;
00662       __n = __n->_M_next();
00663       _M_deallocate_node(__tmp);
00664     }
00665     }
00666 
00667   template<typename _Key, typename _Value,
00668        typename _Allocator, typename _ExtractKey, typename _Equal,
00669        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00670        bool __chc, bool __cit, bool __uk>
00671     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00672             _H1, _H2, _Hash, _RehashPolicy,
00673             __chc, __cit, __uk>::_Bucket*
00674     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00675            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00676     _M_allocate_buckets(size_type __n)
00677     {
00678       _Bucket_allocator_type __alloc(_M_node_allocator);
00679 
00680       _Bucket* __p = __alloc.allocate(__n);
00681       __builtin_memset(__p, 0, __n * sizeof(_Bucket));
00682       return __p;
00683     }
00684 
00685   template<typename _Key, typename _Value,
00686        typename _Allocator, typename _ExtractKey, typename _Equal,
00687        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00688        bool __chc, bool __cit, bool __uk>
00689     void
00690     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00691            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00692     _M_deallocate_buckets(_Bucket* __p, size_type __n)
00693     {
00694       _Bucket_allocator_type __alloc(_M_node_allocator);
00695       __alloc.deallocate(__p, __n);
00696     }
00697 
00698   template<typename _Key, typename _Value,
00699        typename _Allocator, typename _ExtractKey, typename _Equal,
00700        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00701        bool __chc, bool __cit, bool __uk>
00702     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
00703             _Equal, _H1, _H2, _Hash, _RehashPolicy,
00704             __chc, __cit, __uk>::_Node*
00705     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00706            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00707     _M_bucket_begin(size_type __bkt) const
00708     {
00709       _BaseNode* __n = _M_buckets[__bkt];
00710       return __n ? static_cast<_Node*>(__n->_M_nxt) : nullptr;
00711     }
00712 
00713   template<typename _Key, typename _Value,
00714        typename _Allocator, typename _ExtractKey, typename _Equal,
00715        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00716        bool __chc, bool __cit, bool __uk>
00717     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00718            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00719     _Hashtable(size_type __bucket_hint,
00720            const _H1& __h1, const _H2& __h2, const _Hash& __h,
00721            const _Equal& __eq, const _ExtractKey& __exk,
00722            const allocator_type& __a)
00723     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
00724       __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
00725                 _H1, _H2, _Hash, __chc>(__exk, __h1, __h2, __h,
00726                             __eq),
00727       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
00728       _M_node_allocator(__a),
00729       _M_bucket_count(0),
00730       _M_element_count(0),
00731       _M_rehash_policy()
00732     {
00733       _M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
00734       // We don't want the rehash policy to ask for the hashtable to shrink
00735       // on the first insertion so we need to reset its previous resize level.
00736       _M_rehash_policy._M_prev_resize = 0;
00737       _M_buckets = _M_allocate_buckets(_M_bucket_count);
00738     }
00739 
00740   template<typename _Key, typename _Value,
00741        typename _Allocator, typename _ExtractKey, typename _Equal,
00742        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00743        bool __chc, bool __cit, bool __uk>
00744     template<typename _InputIterator>
00745       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00746          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00747       _Hashtable(_InputIterator __f, _InputIterator __l,
00748          size_type __bucket_hint,
00749          const _H1& __h1, const _H2& __h2, const _Hash& __h,
00750          const _Equal& __eq, const _ExtractKey& __exk,
00751          const allocator_type& __a)
00752       : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(),
00753     __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
00754                   _H1, _H2, _Hash, __chc>(__exk, __h1, __h2, __h,
00755                               __eq),
00756     __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(),
00757     _M_node_allocator(__a),
00758     _M_bucket_count(0),
00759     _M_element_count(0),
00760     _M_rehash_policy()
00761       {
00762     _M_bucket_count = std::max(_M_rehash_policy._M_next_bkt(__bucket_hint),
00763                    _M_rehash_policy.
00764                    _M_bkt_for_elements(__detail::
00765                                __distance_fw(__f,
00766                                      __l)));
00767         // We don't want the rehash policy to ask for the hashtable to shrink
00768         // on the first insertion so we need to reset its previous resize
00769     // level.
00770     _M_rehash_policy._M_prev_resize = 0;
00771     _M_buckets = _M_allocate_buckets(_M_bucket_count);
00772     __try
00773       {
00774         for (; __f != __l; ++__f)
00775           this->insert(*__f);
00776       }
00777     __catch(...)
00778       {
00779         clear();
00780         _M_deallocate_buckets(_M_buckets, _M_bucket_count);
00781         __throw_exception_again;
00782       }
00783       }
00784 
00785   template<typename _Key, typename _Value,
00786        typename _Allocator, typename _ExtractKey, typename _Equal,
00787        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00788        bool __chc, bool __cit, bool __uk>
00789     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00790            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00791     _Hashtable(const _Hashtable& __ht)
00792     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
00793       __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
00794                 _H1, _H2, _Hash, __chc>(__ht),
00795       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
00796       _M_node_allocator(__ht._M_node_allocator),
00797       _M_bucket_count(__ht._M_bucket_count),
00798       _M_element_count(__ht._M_element_count),
00799       _M_rehash_policy(__ht._M_rehash_policy)
00800     {
00801       _M_buckets = _M_allocate_buckets(_M_bucket_count);
00802       __try
00803     {
00804       if (!__ht._M_before_begin._M_nxt)
00805         return;
00806 
00807       // First deal with the special first node pointed to by
00808       // _M_before_begin.
00809       const _Node* __ht_n = __ht._M_begin();
00810       _Node* __this_n = _M_allocate_node(__ht_n->_M_v);
00811       this->_M_copy_code(__this_n, __ht_n);
00812       _M_before_begin._M_nxt = __this_n;
00813       _M_buckets[_M_bucket_index(__this_n)] = &_M_before_begin;
00814 
00815       // Then deal with other nodes.
00816       _BaseNode* __prev_n = __this_n;
00817       for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
00818         {
00819           __this_n = _M_allocate_node(__ht_n->_M_v);
00820           __prev_n->_M_nxt = __this_n;
00821           this->_M_copy_code(__this_n, __ht_n);
00822           size_type __bkt = _M_bucket_index(__this_n);
00823           if (!_M_buckets[__bkt])
00824         _M_buckets[__bkt] = __prev_n;
00825           __prev_n = __this_n;
00826         }
00827     }
00828       __catch(...)
00829     {
00830       clear();
00831       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
00832       __throw_exception_again;
00833     }
00834     }
00835 
00836   template<typename _Key, typename _Value,
00837        typename _Allocator, typename _ExtractKey, typename _Equal,
00838        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00839        bool __chc, bool __cit, bool __uk>
00840     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00841            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00842     _Hashtable(_Hashtable&& __ht)
00843     : __detail::_Rehash_base<_RehashPolicy, _Hashtable>(__ht),
00844       __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
00845                 _H1, _H2, _Hash, __chc>(__ht),
00846       __detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
00847       _M_node_allocator(std::move(__ht._M_node_allocator)),
00848       _M_buckets(__ht._M_buckets),
00849       _M_bucket_count(__ht._M_bucket_count),
00850       _M_before_begin(__ht._M_before_begin._M_nxt),
00851       _M_element_count(__ht._M_element_count),
00852       _M_rehash_policy(__ht._M_rehash_policy)
00853     {
00854       // Update, if necessary, bucket pointing to before begin that hasn't move.
00855       if (_M_begin())
00856     _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
00857       __ht._M_rehash_policy = _RehashPolicy();
00858       __ht._M_bucket_count = __ht._M_rehash_policy._M_next_bkt(0);
00859       __ht._M_buckets = __ht._M_allocate_buckets(__ht._M_bucket_count);
00860       __ht._M_before_begin._M_nxt = nullptr;
00861       __ht._M_element_count = 0;
00862     }
00863 
00864   template<typename _Key, typename _Value,
00865        typename _Allocator, typename _ExtractKey, typename _Equal,
00866        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00867        bool __chc, bool __cit, bool __uk>
00868     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00869            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00870     ~_Hashtable() noexcept
00871     {
00872       clear();
00873       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
00874     }
00875 
00876   template<typename _Key, typename _Value,
00877        typename _Allocator, typename _ExtractKey, typename _Equal,
00878        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00879        bool __chc, bool __cit, bool __uk>
00880     void
00881     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00882            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00883     swap(_Hashtable& __x)
00884     {
00885       // The only base class with member variables is hash_code_base.  We
00886       // define _Hash_code_base::_M_swap because different specializations
00887       // have different members.
00888       this->_M_swap(__x);
00889 
00890       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00891       // 431. Swapping containers with unequal allocators.
00892       std::__alloc_swap<_Node_allocator_type>::_S_do_it(_M_node_allocator,
00893                             __x._M_node_allocator);
00894 
00895       std::swap(_M_rehash_policy, __x._M_rehash_policy);
00896       std::swap(_M_buckets, __x._M_buckets);
00897       std::swap(_M_bucket_count, __x._M_bucket_count);
00898       std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
00899       std::swap(_M_element_count, __x._M_element_count);
00900       // Fix buckets containing the _M_before_begin pointers that can't be
00901       // swapped.
00902       if (_M_begin())
00903     _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
00904       if (__x._M_begin())
00905     __x._M_buckets[__x._M_bucket_index(__x._M_begin())]
00906       = &(__x._M_before_begin);
00907     }
00908 
00909   template<typename _Key, typename _Value,
00910        typename _Allocator, typename _ExtractKey, typename _Equal,
00911        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00912        bool __chc, bool __cit, bool __uk>
00913     void
00914     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00915            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00916     __rehash_policy(const _RehashPolicy& __pol)
00917     {
00918       size_type __n_bkt = __pol._M_bkt_for_elements(_M_element_count);
00919       if (__n_bkt != _M_bucket_count)
00920     _M_rehash(__n_bkt, _M_rehash_policy._M_state());
00921       _M_rehash_policy = __pol;
00922     }
00923 
00924   template<typename _Key, typename _Value,
00925        typename _Allocator, typename _ExtractKey, typename _Equal,
00926        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00927        bool __chc, bool __cit, bool __uk>
00928     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00929             _H1, _H2, _Hash, _RehashPolicy,
00930             __chc, __cit, __uk>::iterator
00931     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00932            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00933     find(const key_type& __k)
00934     {
00935       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
00936       std::size_t __n = _M_bucket_index(__k, __code);
00937       _Node* __p = _M_find_node(__n, __k, __code);
00938       return __p ? iterator(__p) : this->end();
00939     }
00940 
00941   template<typename _Key, typename _Value,
00942        typename _Allocator, typename _ExtractKey, typename _Equal,
00943        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00944        bool __chc, bool __cit, bool __uk>
00945     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00946             _H1, _H2, _Hash, _RehashPolicy,
00947             __chc, __cit, __uk>::const_iterator
00948     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00949            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00950     find(const key_type& __k) const
00951     {
00952       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
00953       std::size_t __n = _M_bucket_index(__k, __code);
00954       _Node* __p = _M_find_node(__n, __k, __code);
00955       return __p ? const_iterator(__p) : this->end();
00956     }
00957 
00958   template<typename _Key, typename _Value,
00959        typename _Allocator, typename _ExtractKey, typename _Equal,
00960        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00961        bool __chc, bool __cit, bool __uk>
00962     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00963             _H1, _H2, _Hash, _RehashPolicy,
00964             __chc, __cit, __uk>::size_type
00965     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
00966            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
00967     count(const key_type& __k) const
00968     {
00969       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
00970       std::size_t __n = _M_bucket_index(__k, __code);
00971       _Node* __p = _M_bucket_begin(__n);
00972       if (!__p)
00973     return 0;
00974 
00975       std::size_t __result = 0;
00976       for (;; __p = __p->_M_next())
00977     {
00978       if (this->_M_equals(__k, __code, __p))
00979         ++__result;
00980       else if (__result)
00981         // All equivalent values are next to each other, if we found a not
00982         // equivalent value after an equivalent one it means that we won't
00983         // find anymore an equivalent value.
00984         break;
00985       if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
00986         break;
00987     }
00988       return __result;
00989     }
00990 
00991   template<typename _Key, typename _Value,
00992        typename _Allocator, typename _ExtractKey, typename _Equal,
00993        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
00994        bool __chc, bool __cit, bool __uk>
00995     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
00996                   _ExtractKey, _Equal, _H1,
00997                   _H2, _Hash, _RehashPolicy,
00998                   __chc, __cit, __uk>::iterator,
00999           typename _Hashtable<_Key, _Value, _Allocator,
01000                   _ExtractKey, _Equal, _H1,
01001                   _H2, _Hash, _RehashPolicy,
01002                   __chc, __cit, __uk>::iterator>
01003     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01004            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01005     equal_range(const key_type& __k)
01006     {
01007       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
01008       std::size_t __n = _M_bucket_index(__k, __code);
01009       _Node* __p = _M_find_node(__n, __k, __code);
01010 
01011       if (__p)
01012     {
01013       _Node* __p1 = __p->_M_next();
01014       while (__p1 && _M_bucket_index(__p1) == __n
01015          && this->_M_equals(__k, __code, __p1))
01016         __p1 = __p1->_M_next();
01017 
01018       return std::make_pair(iterator(__p), iterator(__p1));
01019     }
01020       else
01021     return std::make_pair(this->end(), this->end());
01022     }
01023 
01024   template<typename _Key, typename _Value,
01025        typename _Allocator, typename _ExtractKey, typename _Equal,
01026        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01027        bool __chc, bool __cit, bool __uk>
01028     std::pair<typename _Hashtable<_Key, _Value, _Allocator,
01029                   _ExtractKey, _Equal, _H1,
01030                   _H2, _Hash, _RehashPolicy,
01031                   __chc, __cit, __uk>::const_iterator,
01032           typename _Hashtable<_Key, _Value, _Allocator,
01033                   _ExtractKey, _Equal, _H1,
01034                   _H2, _Hash, _RehashPolicy,
01035                   __chc, __cit, __uk>::const_iterator>
01036     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01037            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01038     equal_range(const key_type& __k) const
01039     {
01040       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
01041       std::size_t __n = _M_bucket_index(__k, __code);
01042       _Node* __p = _M_find_node(__n, __k, __code);
01043 
01044       if (__p)
01045     {
01046       _Node* __p1 = __p->_M_next();
01047       while (__p1 && _M_bucket_index(__p1) == __n
01048          && this->_M_equals(__k, __code, __p1))
01049         __p1 = __p1->_M_next();
01050 
01051       return std::make_pair(const_iterator(__p), const_iterator(__p1));
01052     }
01053       else
01054     return std::make_pair(this->end(), this->end());
01055     }
01056 
01057   // Find the node whose key compares equal to k in the bucket n. Return nullptr
01058   // if no node is found.
01059   template<typename _Key, typename _Value,
01060        typename _Allocator, typename _ExtractKey, typename _Equal,
01061        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01062        bool __chc, bool __cit, bool __uk>
01063     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
01064             _Equal, _H1, _H2, _Hash, _RehashPolicy,
01065             __chc, __cit, __uk>::_BaseNode*
01066     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01067            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01068     _M_find_before_node(size_type __n, const key_type& __k,
01069             typename _Hashtable::_Hash_code_type __code) const
01070     {
01071       _BaseNode* __prev_p = _M_buckets[__n];
01072       if (!__prev_p)
01073     return nullptr;
01074       _Node* __p = static_cast<_Node*>(__prev_p->_M_nxt);
01075       for (;; __p = __p->_M_next())
01076     {
01077       if (this->_M_equals(__k, __code, __p))
01078         return __prev_p;
01079       if (!(__p->_M_nxt) || _M_bucket_index(__p->_M_next()) != __n)
01080         break;
01081       __prev_p = __p;
01082     }
01083       return nullptr;
01084     }
01085 
01086   template<typename _Key, typename _Value,
01087        typename _Allocator, typename _ExtractKey, typename _Equal,
01088        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01089        bool __chc, bool __cit, bool __uk>
01090     void
01091     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01092            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01093     _M_insert_bucket_begin(size_type __bkt, _Node* __new_node)
01094     {
01095       if (_M_buckets[__bkt])
01096     {
01097       // Bucket is not empty, we just need to insert the new node after the
01098       // bucket before begin.
01099       __new_node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
01100       _M_buckets[__bkt]->_M_nxt = __new_node;
01101     }
01102       else
01103     {
01104       // The bucket is empty, the new node is inserted at the beginning of
01105       // the singly linked list and the bucket will contain _M_before_begin
01106       // pointer.
01107       __new_node->_M_nxt = _M_before_begin._M_nxt;
01108       _M_before_begin._M_nxt = __new_node;
01109       if (__new_node->_M_nxt)
01110         // We must update former begin bucket that is pointing to
01111         // _M_before_begin.
01112         _M_buckets[_M_bucket_index(__new_node->_M_next())] = __new_node;
01113       _M_buckets[__bkt] = &_M_before_begin;
01114     }
01115     }
01116 
01117   template<typename _Key, typename _Value,
01118        typename _Allocator, typename _ExtractKey, typename _Equal,
01119        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01120        bool __chc, bool __cit, bool __uk>
01121     void
01122     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01123            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01124     _M_remove_bucket_begin(size_type __bkt, _Node* __next, size_type __next_bkt)
01125     {
01126       if (!__next || __next_bkt != __bkt)
01127     {
01128       // Bucket is now empty
01129       // First update next bucket if any
01130       if (__next)
01131         _M_buckets[__next_bkt] = _M_buckets[__bkt];
01132       // Second update before begin node if necessary
01133       if (&_M_before_begin == _M_buckets[__bkt])
01134         _M_before_begin._M_nxt = __next;
01135       _M_buckets[__bkt] = nullptr;
01136     }
01137     }
01138 
01139   template<typename _Key, typename _Value,
01140        typename _Allocator, typename _ExtractKey, typename _Equal,
01141        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01142        bool __chc, bool __cit, bool __uk>
01143     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
01144             _Equal, _H1, _H2, _Hash, _RehashPolicy,
01145             __chc, __cit, __uk>::_BaseNode*
01146     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01147            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01148     _M_get_previous_node(size_type __bkt, _BaseNode* __n)
01149     {
01150       _BaseNode* __prev_n = _M_buckets[__bkt];
01151       while (__prev_n->_M_nxt != __n)
01152     __prev_n = __prev_n->_M_nxt;
01153       return __prev_n;
01154     }
01155 
01156   template<typename _Key, typename _Value,
01157        typename _Allocator, typename _ExtractKey, typename _Equal,
01158        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01159        bool __chc, bool __cit, bool __uk>
01160     template<typename... _Args>
01161       std::pair<typename _Hashtable<_Key, _Value, _Allocator,
01162                     _ExtractKey, _Equal, _H1,
01163                     _H2, _Hash, _RehashPolicy,
01164                     __chc, __cit, __uk>::iterator, bool>
01165       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01166          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01167       _M_emplace(std::true_type, _Args&&... __args)
01168       {
01169     // First build the node to get access to the hash code
01170     _Node* __new_node = _M_allocate_node(std::forward<_Args>(__args)...);
01171     __try
01172       {
01173         const key_type& __k = this->_M_extract()(__new_node->_M_v);
01174         typename _Hashtable::_Hash_code_type __code
01175           = this->_M_hash_code(__k);
01176         size_type __bkt = _M_bucket_index(__k, __code);
01177 
01178         if (_Node* __p = _M_find_node(__bkt, __k, __code))
01179           {
01180         // There is already an equivalent node, no insertion
01181         _M_deallocate_node(__new_node);
01182         return std::make_pair(iterator(__p), false);
01183           }
01184 
01185         // We are going to insert this node
01186         this->_M_store_code(__new_node, __code);
01187         const _RehashPolicyState& __saved_state
01188           = _M_rehash_policy._M_state();
01189         std::pair<bool, std::size_t> __do_rehash
01190           = _M_rehash_policy._M_need_rehash(_M_bucket_count,
01191                         _M_element_count, 1);
01192 
01193         if (__do_rehash.first)
01194           {
01195         _M_rehash(__do_rehash.second, __saved_state);
01196         __bkt = _M_bucket_index(__k, __code);
01197           }
01198 
01199         _M_insert_bucket_begin(__bkt, __new_node);
01200         ++_M_element_count;
01201         return std::make_pair(iterator(__new_node), true);
01202       }
01203     __catch(...)
01204       {
01205         _M_deallocate_node(__new_node);
01206         __throw_exception_again;
01207       }
01208       }
01209 
01210   template<typename _Key, typename _Value,
01211        typename _Allocator, typename _ExtractKey, typename _Equal,
01212        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01213        bool __chc, bool __cit, bool __uk>
01214     template<typename... _Args>
01215       typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01216               _H1, _H2, _Hash, _RehashPolicy,
01217               __chc, __cit, __uk>::iterator
01218       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01219          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01220       _M_emplace(std::false_type, _Args&&... __args)
01221       {
01222     const _RehashPolicyState& __saved_state = _M_rehash_policy._M_state();
01223     std::pair<bool, std::size_t> __do_rehash
01224       = _M_rehash_policy._M_need_rehash(_M_bucket_count,
01225                         _M_element_count, 1);
01226 
01227     // First build the node to get its hash code.
01228     _Node* __new_node = _M_allocate_node(std::forward<_Args>(__args)...);
01229     __try
01230       {
01231         const key_type& __k = this->_M_extract()(__new_node->_M_v);
01232         typename _Hashtable::_Hash_code_type __code
01233           = this->_M_hash_code(__k);
01234         this->_M_store_code(__new_node, __code);
01235 
01236         // Second, do rehash if necessary.
01237         if (__do_rehash.first)
01238         _M_rehash(__do_rehash.second, __saved_state);
01239 
01240         // Third, find the node before an equivalent one.
01241         size_type __bkt = _M_bucket_index(__k, __code);
01242         _BaseNode* __prev = _M_find_before_node(__bkt, __k, __code);
01243         
01244         if (__prev)
01245           {
01246         // Insert after the node before the equivalent one.
01247         __new_node->_M_nxt = __prev->_M_nxt;
01248         __prev->_M_nxt = __new_node;
01249           }
01250         else
01251           // The inserted node has no equivalent in the hashtable. We must
01252           // insert the new node at the beginning of the bucket to preserve
01253           // equivalent elements relative positions.
01254           _M_insert_bucket_begin(__bkt, __new_node);
01255         ++_M_element_count;
01256         return iterator(__new_node);
01257       }
01258     __catch(...)
01259       {
01260         _M_deallocate_node(__new_node);
01261         __throw_exception_again;
01262       }
01263       }
01264 
01265   // Insert v in bucket n (assumes no element with its key already present).
01266   template<typename _Key, typename _Value,
01267        typename _Allocator, typename _ExtractKey, typename _Equal,
01268        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01269        bool __chc, bool __cit, bool __uk>
01270     template<typename _Arg>
01271       typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01272               _H1, _H2, _Hash, _RehashPolicy,
01273               __chc, __cit, __uk>::iterator
01274       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01275          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01276       _M_insert_bucket(_Arg&& __v, size_type __n,
01277                typename _Hashtable::_Hash_code_type __code)
01278       {
01279     const _RehashPolicyState& __saved_state = _M_rehash_policy._M_state();
01280     std::pair<bool, std::size_t> __do_rehash
01281       = _M_rehash_policy._M_need_rehash(_M_bucket_count,
01282                         _M_element_count, 1);
01283 
01284     if (__do_rehash.first)
01285       {
01286         const key_type& __k = this->_M_extract()(__v);
01287         __n = _HCBase::_M_bucket_index(__k, __code, __do_rehash.second);
01288       }
01289 
01290     _Node* __new_node = nullptr;
01291     __try
01292       {
01293         // Allocate the new node before doing the rehash so that we
01294         // don't do a rehash if the allocation throws.
01295         __new_node = _M_allocate_node(std::forward<_Arg>(__v));
01296         this->_M_store_code(__new_node, __code);
01297         if (__do_rehash.first)
01298           _M_rehash(__do_rehash.second, __saved_state);
01299 
01300         _M_insert_bucket_begin(__n, __new_node);
01301         ++_M_element_count;
01302         return iterator(__new_node);
01303       }
01304     __catch(...)
01305       {
01306         if (!__new_node)
01307           _M_rehash_policy._M_reset(__saved_state);
01308         else
01309           _M_deallocate_node(__new_node);
01310         __throw_exception_again;
01311       }
01312       }
01313 
01314   // Insert v if no element with its key is already present.
01315   template<typename _Key, typename _Value,
01316        typename _Allocator, typename _ExtractKey, typename _Equal,
01317        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01318        bool __chc, bool __cit, bool __uk>
01319     template<typename _Arg>
01320       std::pair<typename _Hashtable<_Key, _Value, _Allocator,
01321                     _ExtractKey, _Equal, _H1,
01322                     _H2, _Hash, _RehashPolicy,
01323                     __chc, __cit, __uk>::iterator, bool>
01324       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01325          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01326       _M_insert(_Arg&& __v, std::true_type)
01327       {
01328     const key_type& __k = this->_M_extract()(__v);
01329     typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
01330     size_type __n = _M_bucket_index(__k, __code);
01331 
01332     if (_Node* __p = _M_find_node(__n, __k, __code))
01333       return std::make_pair(iterator(__p), false);
01334     return std::make_pair(_M_insert_bucket(std::forward<_Arg>(__v),
01335                   __n, __code), true);
01336       }
01337 
01338   // Insert v unconditionally.
01339   template<typename _Key, typename _Value,
01340        typename _Allocator, typename _ExtractKey, typename _Equal,
01341        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01342        bool __chc, bool __cit, bool __uk>
01343     template<typename _Arg>
01344       typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01345               _H1, _H2, _Hash, _RehashPolicy,
01346               __chc, __cit, __uk>::iterator
01347       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01348          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01349       _M_insert(_Arg&& __v, std::false_type)
01350       {
01351     const _RehashPolicyState& __saved_state = _M_rehash_policy._M_state();
01352     std::pair<bool, std::size_t> __do_rehash
01353       = _M_rehash_policy._M_need_rehash(_M_bucket_count,
01354                         _M_element_count, 1);
01355 
01356     // First compute the hash code so that we don't do anything if it throws.
01357     typename _Hashtable::_Hash_code_type __code
01358       = this->_M_hash_code(this->_M_extract()(__v));
01359 
01360     _Node* __new_node = nullptr;
01361     __try
01362       {
01363         // Second allocate new node so that we don't rehash if it throws.
01364         __new_node = _M_allocate_node(std::forward<_Arg>(__v));
01365         this->_M_store_code(__new_node, __code);
01366         if (__do_rehash.first)
01367         _M_rehash(__do_rehash.second, __saved_state);
01368 
01369         // Third, find the node before an equivalent one.
01370         size_type __bkt = _M_bucket_index(__new_node);
01371         _BaseNode* __prev
01372           = _M_find_before_node(__bkt, this->_M_extract()(__new_node->_M_v),
01373                     __code);
01374         if (__prev)
01375           {
01376         // Insert after the node before the equivalent one.
01377         __new_node->_M_nxt = __prev->_M_nxt;
01378         __prev->_M_nxt = __new_node;
01379           }
01380         else
01381           // The inserted node has no equivalent in the hashtable. We must
01382           // insert the new node at the beginning of the bucket to preserve
01383           // equivalent elements relative positions.
01384           _M_insert_bucket_begin(__bkt, __new_node);
01385         ++_M_element_count;
01386         return iterator(__new_node);
01387       }
01388     __catch(...)
01389       {
01390         if (!__new_node)
01391           _M_rehash_policy._M_reset(__saved_state);
01392         else
01393           _M_deallocate_node(__new_node);
01394         __throw_exception_again;
01395       }
01396       }
01397 
01398   template<typename _Key, typename _Value,
01399        typename _Allocator, typename _ExtractKey, typename _Equal,
01400        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01401        bool __chc, bool __cit, bool __uk>
01402     template<typename _InputIterator>
01403       void
01404       _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01405          _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01406       insert(_InputIterator __first, _InputIterator __last)
01407       {
01408     size_type __n_elt = __detail::__distance_fw(__first, __last);
01409     const _RehashPolicyState& __saved_state = _M_rehash_policy._M_state();
01410     std::pair<bool, std::size_t> __do_rehash
01411       = _M_rehash_policy._M_need_rehash(_M_bucket_count,
01412                         _M_element_count, __n_elt);
01413     if (__do_rehash.first)
01414       _M_rehash(__do_rehash.second, __saved_state);
01415 
01416     for (; __first != __last; ++__first)
01417       this->insert(*__first);
01418       }
01419 
01420   template<typename _Key, typename _Value,
01421        typename _Allocator, typename _ExtractKey, typename _Equal,
01422        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01423        bool __chc, bool __cit, bool __uk>
01424     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01425             _H1, _H2, _Hash, _RehashPolicy,
01426             __chc, __cit, __uk>::iterator
01427     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01428            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01429     erase(const_iterator __it)
01430     {
01431       _Node* __n = __it._M_cur;
01432       std::size_t __bkt = _M_bucket_index(__n);
01433 
01434       // Look for previous node to unlink it from the erased one, this is why
01435       // we need buckets to contain the before begin to make this research fast.
01436       _BaseNode* __prev_n = _M_get_previous_node(__bkt, __n);
01437       if (__n == _M_bucket_begin(__bkt))
01438     _M_remove_bucket_begin(__bkt, __n->_M_next(),
01439        __n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
01440       else if (__n->_M_nxt)
01441     {
01442       size_type __next_bkt = _M_bucket_index(__n->_M_next());
01443       if (__next_bkt != __bkt)
01444         _M_buckets[__next_bkt] = __prev_n;
01445     }
01446 
01447       __prev_n->_M_nxt = __n->_M_nxt;
01448       iterator __result(__n->_M_next());
01449       _M_deallocate_node(__n);
01450       --_M_element_count;
01451 
01452       return __result;
01453     }
01454 
01455   template<typename _Key, typename _Value,
01456        typename _Allocator, typename _ExtractKey, typename _Equal,
01457        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01458        bool __chc, bool __cit, bool __uk>
01459     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01460             _H1, _H2, _Hash, _RehashPolicy,
01461             __chc, __cit, __uk>::size_type
01462     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01463            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01464     erase(const key_type& __k)
01465     {
01466       typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
01467       std::size_t __bkt = _M_bucket_index(__k, __code);
01468       // Look for the node before the first matching node.
01469       _BaseNode* __prev_n = _M_find_before_node(__bkt, __k, __code);
01470       if (!__prev_n)
01471     return 0;
01472       _Node* __n = static_cast<_Node*>(__prev_n->_M_nxt);
01473       bool __is_bucket_begin = _M_buckets[__bkt] == __prev_n;
01474 
01475       // We found a matching node, start deallocation loop from it
01476       std::size_t __next_bkt = __bkt;
01477       _Node* __next_n = __n;
01478       size_type __result = 0;
01479       _Node* __saved_n = nullptr;
01480       do
01481     {
01482       _Node* __p = __next_n;
01483       __next_n = __p->_M_next();
01484       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01485       // 526. Is it undefined if a function in the standard changes
01486       // in parameters?
01487       if (std::__addressof(this->_M_extract()(__p->_M_v))
01488           != std::__addressof(__k))
01489         _M_deallocate_node(__p);
01490       else
01491         __saved_n = __p;
01492       --_M_element_count;
01493       ++__result;
01494       if (!__next_n)
01495         break;
01496       __next_bkt = _M_bucket_index(__next_n);
01497     }
01498       while (__next_bkt == __bkt && this->_M_equals(__k, __code, __next_n));
01499 
01500       if (__saved_n)
01501     _M_deallocate_node(__saved_n);
01502       if (__is_bucket_begin)
01503     _M_remove_bucket_begin(__bkt, __next_n, __next_bkt);
01504       else if (__next_n && __next_bkt != __bkt)
01505     _M_buckets[__next_bkt] = __prev_n;
01506       if (__prev_n)
01507     __prev_n->_M_nxt = __next_n;
01508       return __result;
01509     }
01510 
01511   template<typename _Key, typename _Value,
01512        typename _Allocator, typename _ExtractKey, typename _Equal,
01513        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01514        bool __chc, bool __cit, bool __uk>
01515     typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01516             _H1, _H2, _Hash, _RehashPolicy,
01517             __chc, __cit, __uk>::iterator
01518     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01519            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01520     erase(const_iterator __first, const_iterator __last)
01521     {
01522       _Node* __n = __first._M_cur;
01523       _Node* __last_n = __last._M_cur;
01524       if (__n == __last_n)
01525     return iterator(__n);
01526 
01527       std::size_t __bkt = _M_bucket_index(__n);
01528 
01529       _BaseNode* __prev_n = _M_get_previous_node(__bkt, __n);
01530       bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
01531       std::size_t __n_bkt = __bkt;
01532       for (;;)
01533     {
01534       do
01535         {
01536           _Node* __tmp = __n;
01537           __n = __n->_M_next();
01538           _M_deallocate_node(__tmp);
01539           --_M_element_count;
01540           if (!__n)
01541         break;
01542           __n_bkt = _M_bucket_index(__n);
01543         }
01544       while (__n != __last_n && __n_bkt == __bkt);
01545       if (__is_bucket_begin)
01546         _M_remove_bucket_begin(__bkt, __n, __n_bkt);
01547       if (__n == __last_n)
01548         break;
01549       __is_bucket_begin = true;
01550       __bkt = __n_bkt;
01551     }
01552 
01553       if (__n && (__n_bkt != __bkt || __is_bucket_begin))
01554     _M_buckets[__n_bkt] = __prev_n;
01555       __prev_n->_M_nxt = __n;
01556       return iterator(__n);
01557     }
01558 
01559   template<typename _Key, typename _Value,
01560        typename _Allocator, typename _ExtractKey, typename _Equal,
01561        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01562        bool __chc, bool __cit, bool __uk>
01563     void
01564     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01565            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01566     clear() noexcept
01567     {
01568       _M_deallocate_nodes(_M_begin());
01569       __builtin_memset(_M_buckets, 0, _M_bucket_count * sizeof(_Bucket));
01570       _M_element_count = 0;
01571       _M_before_begin._M_nxt = nullptr;
01572     }
01573 
01574   template<typename _Key, typename _Value,
01575        typename _Allocator, typename _ExtractKey, typename _Equal,
01576        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01577        bool __chc, bool __cit, bool __uk>
01578     void
01579     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01580            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01581     rehash(size_type __n)
01582     {
01583       const _RehashPolicyState& __saved_state = _M_rehash_policy._M_state();
01584       _M_rehash(std::max(_M_rehash_policy._M_next_bkt(__n),
01585              _M_rehash_policy._M_bkt_for_elements(_M_element_count
01586                                   + 1)),
01587         __saved_state);
01588     }
01589 
01590   template<typename _Key, typename _Value,
01591        typename _Allocator, typename _ExtractKey, typename _Equal,
01592        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01593        bool __chc, bool __cit, bool __uk>
01594     void
01595     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01596            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01597     _M_rehash(size_type __n, const _RehashPolicyState& __state)
01598     {
01599       __try
01600     {
01601       _M_rehash_aux(__n, integral_constant<bool, __uk>());
01602     }
01603       __catch(...)
01604     {
01605       // A failure here means that buckets allocation failed.  We only
01606       // have to restore hash policy previous state.
01607       _M_rehash_policy._M_reset(__state);
01608       __throw_exception_again;
01609     }
01610     }
01611 
01612   // Rehash when there is no equivalent elements.
01613   template<typename _Key, typename _Value,
01614        typename _Allocator, typename _ExtractKey, typename _Equal,
01615        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01616        bool __chc, bool __cit, bool __uk>
01617     void
01618     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01619            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01620     _M_rehash_aux(size_type __n, std::true_type)
01621     {
01622       _Bucket* __new_buckets = _M_allocate_buckets(__n);
01623       _Node* __p = _M_begin();
01624       _M_before_begin._M_nxt = nullptr;
01625       std::size_t __bbegin_bkt;
01626       while (__p)
01627     {
01628       _Node* __next = __p->_M_next();
01629       std::size_t __bkt = _HCBase::_M_bucket_index(__p, __n);
01630       if (!__new_buckets[__bkt])
01631         {
01632           __p->_M_nxt = _M_before_begin._M_nxt;
01633           _M_before_begin._M_nxt = __p;
01634           __new_buckets[__bkt] = &_M_before_begin;
01635           if (__p->_M_nxt)
01636         __new_buckets[__bbegin_bkt] = __p;
01637           __bbegin_bkt = __bkt;
01638         }
01639       else
01640         {
01641           __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
01642           __new_buckets[__bkt]->_M_nxt = __p;
01643         }
01644       __p = __next;
01645     }
01646       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
01647       _M_bucket_count = __n;
01648       _M_buckets = __new_buckets;
01649     }
01650 
01651   // Rehash when there can be equivalent elements, preserve their relative
01652   // order.
01653   template<typename _Key, typename _Value,
01654        typename _Allocator, typename _ExtractKey, typename _Equal,
01655        typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
01656        bool __chc, bool __cit, bool __uk>
01657     void
01658     _Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
01659            _H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
01660     _M_rehash_aux(size_type __n, std::false_type)
01661     {
01662       _Bucket* __new_buckets = _M_allocate_buckets(__n);
01663 
01664       _Node* __p = _M_begin();
01665       _M_before_begin._M_nxt = nullptr;
01666       std::size_t __bbegin_bkt;
01667       std::size_t __prev_bkt;
01668       _Node* __prev_p = nullptr;
01669       bool __check_bucket = false;
01670 
01671       while (__p)
01672     {
01673       bool __check_now = true;
01674       _Node* __next = __p->_M_next();
01675       std::size_t __bkt = _HCBase::_M_bucket_index(__p, __n);
01676 
01677       if (!__new_buckets[__bkt])
01678         {
01679           __p->_M_nxt = _M_before_begin._M_nxt;
01680           _M_before_begin._M_nxt = __p;
01681           __new_buckets[__bkt] = &_M_before_begin;
01682           if (__p->_M_nxt)
01683         __new_buckets[__bbegin_bkt] = __p;
01684           __bbegin_bkt = __bkt;
01685         }
01686       else
01687         {
01688           if (__prev_p && __prev_bkt == __bkt)
01689         {
01690           // Previous insert was already in this bucket, we insert after
01691           // the previously inserted one to preserve equivalent elements
01692           // relative order.
01693           __p->_M_nxt = __prev_p->_M_nxt;
01694           __prev_p->_M_nxt = __p;
01695 
01696           // Inserting after a node in a bucket require to check that we
01697           // haven't change the bucket last node, in this case next
01698           // bucket containing its before begin node must be updated. We
01699           // schedule a check as soon as we move out of the sequence of
01700           // equivalent nodes to limit the number of checks.
01701           __check_bucket = true;
01702           __check_now = false;
01703         }
01704           else
01705         {
01706           __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
01707           __new_buckets[__bkt]->_M_nxt = __p;
01708         }
01709         }
01710       
01711       if (__check_now && __check_bucket)
01712         {
01713           // Check if we shall update the next bucket because of insertions
01714           // into __prev_bkt bucket.
01715           if (__prev_p->_M_nxt)
01716         {
01717           std::size_t __next_bkt
01718             = _HCBase::_M_bucket_index(__prev_p->_M_next(), __n);
01719           if (__next_bkt != __prev_bkt)
01720             __new_buckets[__next_bkt] = __prev_p;
01721         }
01722           __check_bucket = false;
01723         }
01724       __prev_p = __p;
01725       __prev_bkt = __bkt;
01726       __p = __next;
01727     }
01728 
01729       if (__check_bucket && __prev_p->_M_nxt)
01730     {
01731       std::size_t __next_bkt
01732         = _HCBase::_M_bucket_index(__prev_p->_M_next(), __n);
01733       if (__next_bkt != __prev_bkt)
01734         __new_buckets[__next_bkt] = __prev_p;
01735     }
01736 
01737       _M_deallocate_buckets(_M_buckets, _M_bucket_count);
01738       _M_bucket_count = __n;
01739       _M_buckets = __new_buckets;
01740     }
01741 
01742 _GLIBCXX_END_NAMESPACE_VERSION
01743 } // namespace std
01744 
01745 #endif // _HASHTABLE_H