libstdc++
hashtable_policy.h
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00001 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
00002 
00003 // Copyright (C) 2010-2014 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_policy.h
00026  *  This is an internal header file, included by other library headers.
00027  *  Do not attempt to use it directly.
00028  *  @headername{unordered_map,unordered_set}
00029  */
00030 
00031 #ifndef _HASHTABLE_POLICY_H
00032 #define _HASHTABLE_POLICY_H 1
00033 
00034 namespace std _GLIBCXX_VISIBILITY(default)
00035 {
00036 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00037 
00038   template<typename _Key, typename _Value, typename _Alloc,
00039        typename _ExtractKey, typename _Equal,
00040        typename _H1, typename _H2, typename _Hash,
00041        typename _RehashPolicy, typename _Traits>
00042     class _Hashtable;
00043 
00044 _GLIBCXX_END_NAMESPACE_VERSION
00045 
00046 namespace __detail
00047 {
00048 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00049 
00050   /**
00051    *  @defgroup hashtable-detail Base and Implementation Classes
00052    *  @ingroup unordered_associative_containers
00053    *  @{
00054    */
00055   template<typename _Key, typename _Value,
00056        typename _ExtractKey, typename _Equal,
00057        typename _H1, typename _H2, typename _Hash, typename _Traits>
00058     struct _Hashtable_base;
00059 
00060   // Helper function: return distance(first, last) for forward
00061   // iterators, or 0 for input iterators.
00062   template<class _Iterator>
00063     inline typename std::iterator_traits<_Iterator>::difference_type
00064     __distance_fw(_Iterator __first, _Iterator __last,
00065           std::input_iterator_tag)
00066     { return 0; }
00067 
00068   template<class _Iterator>
00069     inline typename std::iterator_traits<_Iterator>::difference_type
00070     __distance_fw(_Iterator __first, _Iterator __last,
00071           std::forward_iterator_tag)
00072     { return std::distance(__first, __last); }
00073 
00074   template<class _Iterator>
00075     inline typename std::iterator_traits<_Iterator>::difference_type
00076     __distance_fw(_Iterator __first, _Iterator __last)
00077     {
00078       typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag;
00079       return __distance_fw(__first, __last, _Tag());
00080     }
00081 
00082   // Helper type used to detect whether the hash functor is noexcept.
00083   template <typename _Key, typename _Hash>
00084     struct __is_noexcept_hash : std::integral_constant<bool,
00085     noexcept(declval<const _Hash&>()(declval<const _Key&>()))>
00086     { };
00087 
00088   struct _Identity
00089   {
00090     template<typename _Tp>
00091       _Tp&&
00092       operator()(_Tp&& __x) const
00093       { return std::forward<_Tp>(__x); }
00094   };
00095 
00096   struct _Select1st
00097   {
00098     template<typename _Tp>
00099       auto
00100       operator()(_Tp&& __x) const
00101       -> decltype(std::get<0>(std::forward<_Tp>(__x)))
00102       { return std::get<0>(std::forward<_Tp>(__x)); }
00103   };
00104 
00105   template<typename _NodeAlloc>
00106     struct _Hashtable_alloc;
00107 
00108   // Functor recycling a pool of nodes and using allocation once the pool is
00109   // empty.
00110   template<typename _NodeAlloc>
00111     struct _ReuseOrAllocNode
00112     {
00113     private:
00114       using __node_alloc_type = _NodeAlloc;
00115       using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
00116       using __value_alloc_type = typename __hashtable_alloc::__value_alloc_type;
00117       using __value_alloc_traits =
00118     typename __hashtable_alloc::__value_alloc_traits;
00119       using __node_alloc_traits =
00120     typename __hashtable_alloc::__node_alloc_traits;
00121       using __node_type = typename __hashtable_alloc::__node_type;
00122 
00123     public:
00124       _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
00125     : _M_nodes(__nodes), _M_h(__h) { }
00126       _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
00127 
00128       ~_ReuseOrAllocNode()
00129       { _M_h._M_deallocate_nodes(_M_nodes); }
00130 
00131       template<typename _Arg>
00132     __node_type*
00133     operator()(_Arg&& __arg) const
00134     {
00135       if (_M_nodes)
00136         {
00137           __node_type* __node = _M_nodes;
00138           _M_nodes = _M_nodes->_M_next();
00139           __node->_M_nxt = nullptr;
00140           __value_alloc_type __a(_M_h._M_node_allocator());
00141           __value_alloc_traits::destroy(__a, __node->_M_valptr());
00142           __try
00143         {
00144           __value_alloc_traits::construct(__a, __node->_M_valptr(),
00145                           std::forward<_Arg>(__arg));
00146         }
00147           __catch(...)
00148         {
00149           __node->~__node_type();
00150           __node_alloc_traits::deallocate(_M_h._M_node_allocator(),
00151                           __node, 1);
00152           __throw_exception_again;
00153         }
00154           return __node;
00155         }
00156       return _M_h._M_allocate_node(std::forward<_Arg>(__arg));
00157     }
00158 
00159     private:
00160       mutable __node_type* _M_nodes;
00161       __hashtable_alloc& _M_h;
00162     };
00163 
00164   // Functor similar to the previous one but without any pool of nodes to
00165   // recycle.
00166   template<typename _NodeAlloc>
00167     struct _AllocNode
00168     {
00169     private:
00170       using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
00171       using __node_type = typename __hashtable_alloc::__node_type;
00172 
00173     public:
00174       _AllocNode(__hashtable_alloc& __h)
00175     : _M_h(__h) { }
00176 
00177       template<typename _Arg>
00178     __node_type*
00179     operator()(_Arg&& __arg) const
00180     { return _M_h._M_allocate_node(std::forward<_Arg>(__arg)); }
00181 
00182     private:
00183       __hashtable_alloc& _M_h;
00184     };
00185 
00186   // Auxiliary types used for all instantiations of _Hashtable nodes
00187   // and iterators.
00188 
00189   /**
00190    *  struct _Hashtable_traits
00191    *
00192    *  Important traits for hash tables.
00193    *
00194    *  @tparam _Cache_hash_code  Boolean value. True if the value of
00195    *  the hash function is stored along with the value. This is a
00196    *  time-space tradeoff.  Storing it may improve lookup speed by
00197    *  reducing the number of times we need to call the _Equal
00198    *  function.
00199    *
00200    *  @tparam _Constant_iterators  Boolean value. True if iterator and
00201    *  const_iterator are both constant iterator types. This is true
00202    *  for unordered_set and unordered_multiset, false for
00203    *  unordered_map and unordered_multimap.
00204    *
00205    *  @tparam _Unique_keys  Boolean value. True if the return value
00206    *  of _Hashtable::count(k) is always at most one, false if it may
00207    *  be an arbitrary number. This is true for unordered_set and
00208    *  unordered_map, false for unordered_multiset and
00209    *  unordered_multimap.
00210    */
00211   template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
00212     struct _Hashtable_traits
00213     {
00214       template<bool _Cond>
00215     using __bool_constant = integral_constant<bool, _Cond>;
00216 
00217       using __hash_cached = __bool_constant<_Cache_hash_code>;
00218       using __constant_iterators = __bool_constant<_Constant_iterators>;
00219       using __unique_keys = __bool_constant<_Unique_keys>;
00220     };
00221 
00222   /**
00223    *  struct _Hash_node_base
00224    *
00225    *  Nodes, used to wrap elements stored in the hash table.  A policy
00226    *  template parameter of class template _Hashtable controls whether
00227    *  nodes also store a hash code. In some cases (e.g. strings) this
00228    *  may be a performance win.
00229    */
00230   struct _Hash_node_base
00231   {
00232     _Hash_node_base* _M_nxt;
00233 
00234     _Hash_node_base() noexcept : _M_nxt() { }
00235 
00236     _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
00237   };
00238 
00239   /**
00240    *  struct _Hash_node_value_base
00241    *
00242    *  Node type with the value to store.
00243    */
00244   template<typename _Value>
00245     struct _Hash_node_value_base : _Hash_node_base
00246     {
00247       typedef _Value value_type;
00248 
00249       __gnu_cxx::__aligned_buffer<_Value> _M_storage;
00250 
00251       _Value*
00252       _M_valptr() noexcept
00253       { return _M_storage._M_ptr(); }
00254 
00255       const _Value*
00256       _M_valptr() const noexcept
00257       { return _M_storage._M_ptr(); }
00258 
00259       _Value&
00260       _M_v() noexcept
00261       { return *_M_valptr(); }
00262 
00263       const _Value&
00264       _M_v() const noexcept
00265       { return *_M_valptr(); }
00266     };
00267 
00268   /**
00269    *  Primary template struct _Hash_node.
00270    */
00271   template<typename _Value, bool _Cache_hash_code>
00272     struct _Hash_node;
00273 
00274   /**
00275    *  Specialization for nodes with caches, struct _Hash_node.
00276    *
00277    *  Base class is __detail::_Hash_node_value_base.
00278    */
00279   template<typename _Value>
00280     struct _Hash_node<_Value, true> : _Hash_node_value_base<_Value>
00281     {
00282       std::size_t  _M_hash_code;
00283 
00284       _Hash_node*
00285       _M_next() const noexcept
00286       { return static_cast<_Hash_node*>(this->_M_nxt); }
00287     };
00288 
00289   /**
00290    *  Specialization for nodes without caches, struct _Hash_node.
00291    *
00292    *  Base class is __detail::_Hash_node_value_base.
00293    */
00294   template<typename _Value>
00295     struct _Hash_node<_Value, false> : _Hash_node_value_base<_Value>
00296     {
00297       _Hash_node*
00298       _M_next() const noexcept
00299       { return static_cast<_Hash_node*>(this->_M_nxt); }
00300     };
00301 
00302   /// Base class for node iterators.
00303   template<typename _Value, bool _Cache_hash_code>
00304     struct _Node_iterator_base
00305     {
00306       using __node_type = _Hash_node<_Value, _Cache_hash_code>;
00307 
00308       __node_type*  _M_cur;
00309 
00310       _Node_iterator_base(__node_type* __p) noexcept
00311       : _M_cur(__p) { }
00312 
00313       void
00314       _M_incr() noexcept
00315       { _M_cur = _M_cur->_M_next(); }
00316     };
00317 
00318   template<typename _Value, bool _Cache_hash_code>
00319     inline bool
00320     operator==(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
00321            const _Node_iterator_base<_Value, _Cache_hash_code >& __y)
00322     noexcept
00323     { return __x._M_cur == __y._M_cur; }
00324 
00325   template<typename _Value, bool _Cache_hash_code>
00326     inline bool
00327     operator!=(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
00328            const _Node_iterator_base<_Value, _Cache_hash_code>& __y)
00329     noexcept
00330     { return __x._M_cur != __y._M_cur; }
00331 
00332   /// Node iterators, used to iterate through all the hashtable.
00333   template<typename _Value, bool __constant_iterators, bool __cache>
00334     struct _Node_iterator
00335     : public _Node_iterator_base<_Value, __cache>
00336     {
00337     private:
00338       using __base_type = _Node_iterator_base<_Value, __cache>;
00339       using __node_type = typename __base_type::__node_type;
00340 
00341     public:
00342       typedef _Value                    value_type;
00343       typedef std::ptrdiff_t                difference_type;
00344       typedef std::forward_iterator_tag         iterator_category;
00345 
00346       using pointer = typename std::conditional<__constant_iterators,
00347                         const _Value*, _Value*>::type;
00348 
00349       using reference = typename std::conditional<__constant_iterators,
00350                           const _Value&, _Value&>::type;
00351 
00352       _Node_iterator() noexcept
00353       : __base_type(0) { }
00354 
00355       explicit
00356       _Node_iterator(__node_type* __p) noexcept
00357       : __base_type(__p) { }
00358 
00359       reference
00360       operator*() const noexcept
00361       { return this->_M_cur->_M_v(); }
00362 
00363       pointer
00364       operator->() const noexcept
00365       { return this->_M_cur->_M_valptr(); }
00366 
00367       _Node_iterator&
00368       operator++() noexcept
00369       {
00370     this->_M_incr();
00371     return *this;
00372       }
00373 
00374       _Node_iterator
00375       operator++(int) noexcept
00376       {
00377     _Node_iterator __tmp(*this);
00378     this->_M_incr();
00379     return __tmp;
00380       }
00381     };
00382 
00383   /// Node const_iterators, used to iterate through all the hashtable.
00384   template<typename _Value, bool __constant_iterators, bool __cache>
00385     struct _Node_const_iterator
00386     : public _Node_iterator_base<_Value, __cache>
00387     {
00388     private:
00389       using __base_type = _Node_iterator_base<_Value, __cache>;
00390       using __node_type = typename __base_type::__node_type;
00391 
00392     public:
00393       typedef _Value                    value_type;
00394       typedef std::ptrdiff_t                difference_type;
00395       typedef std::forward_iterator_tag         iterator_category;
00396 
00397       typedef const _Value*             pointer;
00398       typedef const _Value&             reference;
00399 
00400       _Node_const_iterator() noexcept
00401       : __base_type(0) { }
00402 
00403       explicit
00404       _Node_const_iterator(__node_type* __p) noexcept
00405       : __base_type(__p) { }
00406 
00407       _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
00408                __cache>& __x) noexcept
00409       : __base_type(__x._M_cur) { }
00410 
00411       reference
00412       operator*() const noexcept
00413       { return this->_M_cur->_M_v(); }
00414 
00415       pointer
00416       operator->() const noexcept
00417       { return this->_M_cur->_M_valptr(); }
00418 
00419       _Node_const_iterator&
00420       operator++() noexcept
00421       {
00422     this->_M_incr();
00423     return *this;
00424       }
00425 
00426       _Node_const_iterator
00427       operator++(int) noexcept
00428       {
00429     _Node_const_iterator __tmp(*this);
00430     this->_M_incr();
00431     return __tmp;
00432       }
00433     };
00434 
00435   // Many of class template _Hashtable's template parameters are policy
00436   // classes.  These are defaults for the policies.
00437 
00438   /// Default range hashing function: use division to fold a large number
00439   /// into the range [0, N).
00440   struct _Mod_range_hashing
00441   {
00442     typedef std::size_t first_argument_type;
00443     typedef std::size_t second_argument_type;
00444     typedef std::size_t result_type;
00445 
00446     result_type
00447     operator()(first_argument_type __num,
00448            second_argument_type __den) const noexcept
00449     { return __num % __den; }
00450   };
00451 
00452   /// Default ranged hash function H.  In principle it should be a
00453   /// function object composed from objects of type H1 and H2 such that
00454   /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
00455   /// h1 and h2.  So instead we'll just use a tag to tell class template
00456   /// hashtable to do that composition.
00457   struct _Default_ranged_hash { };
00458 
00459   /// Default value for rehash policy.  Bucket size is (usually) the
00460   /// smallest prime that keeps the load factor small enough.
00461   struct _Prime_rehash_policy
00462   {
00463     _Prime_rehash_policy(float __z = 1.0)
00464     : _M_max_load_factor(__z), _M_next_resize(0) { }
00465 
00466     float
00467     max_load_factor() const noexcept
00468     { return _M_max_load_factor; }
00469 
00470     // Return a bucket size no smaller than n.
00471     std::size_t
00472     _M_next_bkt(std::size_t __n) const;
00473 
00474     // Return a bucket count appropriate for n elements
00475     std::size_t
00476     _M_bkt_for_elements(std::size_t __n) const
00477     { return __builtin_ceil(__n / (long double)_M_max_load_factor); }
00478 
00479     // __n_bkt is current bucket count, __n_elt is current element count,
00480     // and __n_ins is number of elements to be inserted.  Do we need to
00481     // increase bucket count?  If so, return make_pair(true, n), where n
00482     // is the new bucket count.  If not, return make_pair(false, 0).
00483     std::pair<bool, std::size_t>
00484     _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
00485            std::size_t __n_ins) const;
00486 
00487     typedef std::size_t _State;
00488 
00489     _State
00490     _M_state() const
00491     { return _M_next_resize; }
00492 
00493     void
00494     _M_reset() noexcept
00495     { _M_next_resize = 0; }
00496 
00497     void
00498     _M_reset(_State __state)
00499     { _M_next_resize = __state; }
00500 
00501     enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 };
00502 
00503     static const std::size_t _S_growth_factor = 2;
00504 
00505     float       _M_max_load_factor;
00506     mutable std::size_t _M_next_resize;
00507   };
00508 
00509   // Base classes for std::_Hashtable.  We define these base classes
00510   // because in some cases we want to do different things depending on
00511   // the value of a policy class.  In some cases the policy class
00512   // affects which member functions and nested typedefs are defined;
00513   // we handle that by specializing base class templates.  Several of
00514   // the base class templates need to access other members of class
00515   // template _Hashtable, so we use a variant of the "Curiously
00516   // Recurring Template Pattern" (CRTP) technique.
00517 
00518   /**
00519    *  Primary class template _Map_base.
00520    *
00521    *  If the hashtable has a value type of the form pair<T1, T2> and a
00522    *  key extraction policy (_ExtractKey) that returns the first part
00523    *  of the pair, the hashtable gets a mapped_type typedef.  If it
00524    *  satisfies those criteria and also has unique keys, then it also
00525    *  gets an operator[].
00526    */
00527   template<typename _Key, typename _Value, typename _Alloc,
00528        typename _ExtractKey, typename _Equal,
00529        typename _H1, typename _H2, typename _Hash,
00530        typename _RehashPolicy, typename _Traits,
00531        bool _Unique_keys = _Traits::__unique_keys::value>
00532     struct _Map_base { };
00533 
00534   /// Partial specialization, __unique_keys set to false.
00535   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00536        typename _H1, typename _H2, typename _Hash,
00537        typename _RehashPolicy, typename _Traits>
00538     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00539              _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
00540     {
00541       using mapped_type = typename std::tuple_element<1, _Pair>::type;
00542     };
00543 
00544   /// Partial specialization, __unique_keys set to true.
00545   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00546        typename _H1, typename _H2, typename _Hash,
00547        typename _RehashPolicy, typename _Traits>
00548     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00549              _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
00550     {
00551     private:
00552       using __hashtable_base = __detail::_Hashtable_base<_Key, _Pair,
00553                              _Select1st,
00554                             _Equal, _H1, _H2, _Hash,
00555                               _Traits>;
00556 
00557       using __hashtable = _Hashtable<_Key, _Pair, _Alloc,
00558                      _Select1st, _Equal,
00559                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
00560 
00561       using __hash_code = typename __hashtable_base::__hash_code;
00562       using __node_type = typename __hashtable_base::__node_type;
00563 
00564     public:
00565       using key_type = typename __hashtable_base::key_type;
00566       using iterator = typename __hashtable_base::iterator;
00567       using mapped_type = typename std::tuple_element<1, _Pair>::type;
00568 
00569       mapped_type&
00570       operator[](const key_type& __k);
00571 
00572       mapped_type&
00573       operator[](key_type&& __k);
00574 
00575       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00576       // DR 761. unordered_map needs an at() member function.
00577       mapped_type&
00578       at(const key_type& __k);
00579 
00580       const mapped_type&
00581       at(const key_type& __k) const;
00582     };
00583 
00584   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00585        typename _H1, typename _H2, typename _Hash,
00586        typename _RehashPolicy, typename _Traits>
00587     typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00588                _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
00589                ::mapped_type&
00590     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00591           _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00592     operator[](const key_type& __k)
00593     {
00594       __hashtable* __h = static_cast<__hashtable*>(this);
00595       __hash_code __code = __h->_M_hash_code(__k);
00596       std::size_t __n = __h->_M_bucket_index(__k, __code);
00597       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00598 
00599       if (!__p)
00600     {
00601       __p = __h->_M_allocate_node(std::piecewise_construct,
00602                       std::tuple<const key_type&>(__k),
00603                       std::tuple<>());
00604       return __h->_M_insert_unique_node(__n, __code, __p)->second;
00605     }
00606 
00607       return __p->_M_v().second;
00608     }
00609 
00610   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00611        typename _H1, typename _H2, typename _Hash,
00612        typename _RehashPolicy, typename _Traits>
00613     typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00614                _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
00615                ::mapped_type&
00616     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00617           _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00618     operator[](key_type&& __k)
00619     {
00620       __hashtable* __h = static_cast<__hashtable*>(this);
00621       __hash_code __code = __h->_M_hash_code(__k);
00622       std::size_t __n = __h->_M_bucket_index(__k, __code);
00623       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00624 
00625       if (!__p)
00626     {
00627       __p = __h->_M_allocate_node(std::piecewise_construct,
00628                       std::forward_as_tuple(std::move(__k)),
00629                       std::tuple<>());
00630       return __h->_M_insert_unique_node(__n, __code, __p)->second;
00631     }
00632 
00633       return __p->_M_v().second;
00634     }
00635 
00636   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00637        typename _H1, typename _H2, typename _Hash,
00638        typename _RehashPolicy, typename _Traits>
00639     typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00640                _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
00641                ::mapped_type&
00642     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00643           _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00644     at(const key_type& __k)
00645     {
00646       __hashtable* __h = static_cast<__hashtable*>(this);
00647       __hash_code __code = __h->_M_hash_code(__k);
00648       std::size_t __n = __h->_M_bucket_index(__k, __code);
00649       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00650 
00651       if (!__p)
00652     __throw_out_of_range(__N("_Map_base::at"));
00653       return __p->_M_v().second;
00654     }
00655 
00656   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00657        typename _H1, typename _H2, typename _Hash,
00658        typename _RehashPolicy, typename _Traits>
00659     const typename _Map_base<_Key, _Pair, _Alloc, _Select1st,
00660                  _Equal, _H1, _H2, _Hash, _RehashPolicy,
00661                  _Traits, true>::mapped_type&
00662     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00663           _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00664     at(const key_type& __k) const
00665     {
00666       const __hashtable* __h = static_cast<const __hashtable*>(this);
00667       __hash_code __code = __h->_M_hash_code(__k);
00668       std::size_t __n = __h->_M_bucket_index(__k, __code);
00669       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00670 
00671       if (!__p)
00672     __throw_out_of_range(__N("_Map_base::at"));
00673       return __p->_M_v().second;
00674     }
00675 
00676   /**
00677    *  Primary class template _Insert_base.
00678    *
00679    *  insert member functions appropriate to all _Hashtables.
00680    */
00681   template<typename _Key, typename _Value, typename _Alloc,
00682        typename _ExtractKey, typename _Equal,
00683        typename _H1, typename _H2, typename _Hash,
00684        typename _RehashPolicy, typename _Traits>
00685     struct _Insert_base
00686     {
00687     protected:
00688       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
00689                      _Equal, _H1, _H2, _Hash,
00690                      _RehashPolicy, _Traits>;
00691 
00692       using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
00693                            _Equal, _H1, _H2, _Hash,
00694                            _Traits>;
00695 
00696       using value_type = typename __hashtable_base::value_type;
00697       using iterator = typename __hashtable_base::iterator;
00698       using const_iterator =  typename __hashtable_base::const_iterator;
00699       using size_type = typename __hashtable_base::size_type;
00700 
00701       using __unique_keys = typename __hashtable_base::__unique_keys;
00702       using __ireturn_type = typename __hashtable_base::__ireturn_type;
00703       using __node_type = _Hash_node<_Value, _Traits::__hash_cached::value>;
00704       using __node_alloc_type =
00705     typename __alloctr_rebind<_Alloc, __node_type>::__type;
00706       using __node_gen_type = _AllocNode<__node_alloc_type>;
00707 
00708       __hashtable&
00709       _M_conjure_hashtable()
00710       { return *(static_cast<__hashtable*>(this)); }
00711 
00712       template<typename _InputIterator, typename _NodeGetter>
00713     void
00714     _M_insert_range(_InputIterator __first, _InputIterator __last,
00715             const _NodeGetter&);
00716 
00717     public:
00718       __ireturn_type
00719       insert(const value_type& __v)
00720       {
00721     __hashtable& __h = _M_conjure_hashtable();
00722     __node_gen_type __node_gen(__h);
00723     return __h._M_insert(__v, __node_gen, __unique_keys());
00724       }
00725 
00726       iterator
00727       insert(const_iterator __hint, const value_type& __v)
00728       {
00729     __hashtable& __h = _M_conjure_hashtable();
00730     __node_gen_type __node_gen(__h);    
00731     return __h._M_insert(__hint, __v, __node_gen, __unique_keys());
00732       }
00733 
00734       void
00735       insert(initializer_list<value_type> __l)
00736       { this->insert(__l.begin(), __l.end()); }
00737 
00738       template<typename _InputIterator>
00739     void
00740     insert(_InputIterator __first, _InputIterator __last)
00741     {
00742       __hashtable& __h = _M_conjure_hashtable();
00743       __node_gen_type __node_gen(__h);
00744       return _M_insert_range(__first, __last, __node_gen);
00745     }
00746     };
00747 
00748   template<typename _Key, typename _Value, typename _Alloc,
00749        typename _ExtractKey, typename _Equal,
00750        typename _H1, typename _H2, typename _Hash,
00751        typename _RehashPolicy, typename _Traits>
00752     template<typename _InputIterator, typename _NodeGetter>
00753       void
00754       _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00755             _RehashPolicy, _Traits>::
00756       _M_insert_range(_InputIterator __first, _InputIterator __last,
00757               const _NodeGetter& __node_gen)
00758       {
00759     using __rehash_type = typename __hashtable::__rehash_type;
00760     using __rehash_state = typename __hashtable::__rehash_state;
00761     using pair_type = std::pair<bool, std::size_t>;
00762 
00763     size_type __n_elt = __detail::__distance_fw(__first, __last);
00764 
00765     __hashtable& __h = _M_conjure_hashtable();
00766     __rehash_type& __rehash = __h._M_rehash_policy;
00767     const __rehash_state& __saved_state = __rehash._M_state();
00768     pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
00769                             __h._M_element_count,
00770                             __n_elt);
00771 
00772     if (__do_rehash.first)
00773       __h._M_rehash(__do_rehash.second, __saved_state);
00774 
00775     for (; __first != __last; ++__first)
00776       __h._M_insert(*__first, __node_gen, __unique_keys());
00777       }
00778 
00779   /**
00780    *  Primary class template _Insert.
00781    *
00782    *  Select insert member functions appropriate to _Hashtable policy choices.
00783    */
00784   template<typename _Key, typename _Value, typename _Alloc,
00785        typename _ExtractKey, typename _Equal,
00786        typename _H1, typename _H2, typename _Hash,
00787        typename _RehashPolicy, typename _Traits,
00788        bool _Constant_iterators = _Traits::__constant_iterators::value,
00789        bool _Unique_keys = _Traits::__unique_keys::value>
00790     struct _Insert;
00791 
00792   /// Specialization.
00793   template<typename _Key, typename _Value, typename _Alloc,
00794        typename _ExtractKey, typename _Equal,
00795        typename _H1, typename _H2, typename _Hash,
00796        typename _RehashPolicy, typename _Traits>
00797     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00798            _RehashPolicy, _Traits, true, true>
00799     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00800                _H1, _H2, _Hash, _RehashPolicy, _Traits>
00801     {
00802       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00803                     _Equal, _H1, _H2, _Hash,
00804                     _RehashPolicy, _Traits>;
00805       using value_type = typename __base_type::value_type;
00806       using iterator = typename __base_type::iterator;
00807       using const_iterator =  typename __base_type::const_iterator;
00808 
00809       using __unique_keys = typename __base_type::__unique_keys;
00810       using __hashtable = typename __base_type::__hashtable;
00811       using __node_gen_type = typename __base_type::__node_gen_type;
00812 
00813       using __base_type::insert;
00814 
00815       std::pair<iterator, bool>
00816       insert(value_type&& __v)
00817       {
00818     __hashtable& __h = this->_M_conjure_hashtable();
00819     __node_gen_type __node_gen(__h);
00820     return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
00821       }
00822 
00823       iterator
00824       insert(const_iterator __hint, value_type&& __v)
00825       {
00826     __hashtable& __h = this->_M_conjure_hashtable();
00827     __node_gen_type __node_gen(__h);
00828     return __h._M_insert(__hint, std::move(__v), __node_gen,
00829                  __unique_keys());
00830       }
00831     };
00832 
00833   /// Specialization.
00834   template<typename _Key, typename _Value, typename _Alloc,
00835        typename _ExtractKey, typename _Equal,
00836        typename _H1, typename _H2, typename _Hash,
00837        typename _RehashPolicy, typename _Traits>
00838     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00839            _RehashPolicy, _Traits, true, false>
00840     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00841                _H1, _H2, _Hash, _RehashPolicy, _Traits>
00842     {
00843       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00844                     _Equal, _H1, _H2, _Hash,
00845                     _RehashPolicy, _Traits>;
00846       using value_type = typename __base_type::value_type;
00847       using iterator = typename __base_type::iterator;
00848       using const_iterator =  typename __base_type::const_iterator;
00849 
00850       using __unique_keys = typename __base_type::__unique_keys;
00851       using __hashtable = typename __base_type::__hashtable;
00852       using __node_gen_type = typename __base_type::__node_gen_type;
00853 
00854       using __base_type::insert;
00855 
00856       iterator
00857       insert(value_type&& __v)
00858       {
00859     __hashtable& __h = this->_M_conjure_hashtable();
00860     __node_gen_type __node_gen(__h);
00861     return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
00862       }
00863 
00864       iterator
00865       insert(const_iterator __hint, value_type&& __v)
00866       {
00867     __hashtable& __h = this->_M_conjure_hashtable();
00868     __node_gen_type __node_gen(__h);
00869     return __h._M_insert(__hint, std::move(__v), __node_gen,
00870                  __unique_keys());
00871       }
00872     };
00873 
00874   /// Specialization.
00875   template<typename _Key, typename _Value, typename _Alloc,
00876        typename _ExtractKey, typename _Equal,
00877        typename _H1, typename _H2, typename _Hash,
00878        typename _RehashPolicy, typename _Traits, bool _Unique_keys>
00879     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00880            _RehashPolicy, _Traits, false, _Unique_keys>
00881     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00882                _H1, _H2, _Hash, _RehashPolicy, _Traits>
00883     {
00884       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00885                        _Equal, _H1, _H2, _Hash,
00886                        _RehashPolicy, _Traits>;
00887       using value_type = typename __base_type::value_type;
00888       using iterator = typename __base_type::iterator;
00889       using const_iterator =  typename __base_type::const_iterator;
00890 
00891       using __unique_keys = typename __base_type::__unique_keys;
00892       using __hashtable = typename __base_type::__hashtable;
00893       using __ireturn_type = typename __base_type::__ireturn_type;
00894 
00895       using __base_type::insert;
00896 
00897       template<typename _Pair>
00898     using __is_cons = std::is_constructible<value_type, _Pair&&>;
00899 
00900       template<typename _Pair>
00901     using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
00902 
00903       template<typename _Pair>
00904     using _IFconsp = typename _IFcons<_Pair>::type;
00905 
00906       template<typename _Pair, typename = _IFconsp<_Pair>>
00907     __ireturn_type
00908     insert(_Pair&& __v)
00909     {
00910       __hashtable& __h = this->_M_conjure_hashtable();
00911       return __h._M_emplace(__unique_keys(), std::forward<_Pair>(__v));
00912     }
00913 
00914       template<typename _Pair, typename = _IFconsp<_Pair>>
00915     iterator
00916     insert(const_iterator __hint, _Pair&& __v)
00917     {
00918       __hashtable& __h = this->_M_conjure_hashtable();
00919       return __h._M_emplace(__hint, __unique_keys(),
00920                 std::forward<_Pair>(__v));
00921     }
00922    };
00923 
00924   /**
00925    *  Primary class template  _Rehash_base.
00926    *
00927    *  Give hashtable the max_load_factor functions and reserve iff the
00928    *  rehash policy is _Prime_rehash_policy.
00929   */
00930   template<typename _Key, typename _Value, typename _Alloc,
00931        typename _ExtractKey, typename _Equal,
00932        typename _H1, typename _H2, typename _Hash,
00933        typename _RehashPolicy, typename _Traits>
00934     struct _Rehash_base;
00935 
00936   /// Specialization.
00937   template<typename _Key, typename _Value, typename _Alloc,
00938        typename _ExtractKey, typename _Equal,
00939        typename _H1, typename _H2, typename _Hash, typename _Traits>
00940     struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00941             _H1, _H2, _Hash, _Prime_rehash_policy, _Traits>
00942     {
00943       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
00944                      _Equal, _H1, _H2, _Hash,
00945                      _Prime_rehash_policy, _Traits>;
00946 
00947       float
00948       max_load_factor() const noexcept
00949       {
00950     const __hashtable* __this = static_cast<const __hashtable*>(this);
00951     return __this->__rehash_policy().max_load_factor();
00952       }
00953 
00954       void
00955       max_load_factor(float __z)
00956       {
00957     __hashtable* __this = static_cast<__hashtable*>(this);
00958     __this->__rehash_policy(_Prime_rehash_policy(__z));
00959       }
00960 
00961       void
00962       reserve(std::size_t __n)
00963       {
00964     __hashtable* __this = static_cast<__hashtable*>(this);
00965     __this->rehash(__builtin_ceil(__n / max_load_factor()));
00966       }
00967     };
00968 
00969   /**
00970    *  Primary class template _Hashtable_ebo_helper.
00971    *
00972    *  Helper class using EBO when it is not forbidden (the type is not
00973    *  final) and when it is worth it (the type is empty.)
00974    */
00975   template<int _Nm, typename _Tp,
00976        bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
00977     struct _Hashtable_ebo_helper;
00978 
00979   /// Specialization using EBO.
00980   template<int _Nm, typename _Tp>
00981     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
00982     : private _Tp
00983     {
00984       _Hashtable_ebo_helper() = default;
00985 
00986       template<typename _OtherTp>
00987     _Hashtable_ebo_helper(_OtherTp&& __tp)
00988       : _Tp(std::forward<_OtherTp>(__tp))
00989     { }
00990 
00991       static const _Tp&
00992       _S_cget(const _Hashtable_ebo_helper& __eboh)
00993       { return static_cast<const _Tp&>(__eboh); }
00994 
00995       static _Tp&
00996       _S_get(_Hashtable_ebo_helper& __eboh)
00997       { return static_cast<_Tp&>(__eboh); }
00998     };
00999 
01000   /// Specialization not using EBO.
01001   template<int _Nm, typename _Tp>
01002     struct _Hashtable_ebo_helper<_Nm, _Tp, false>
01003     {
01004       _Hashtable_ebo_helper() = default;
01005 
01006       template<typename _OtherTp>
01007     _Hashtable_ebo_helper(_OtherTp&& __tp)
01008       : _M_tp(std::forward<_OtherTp>(__tp))
01009     { }
01010 
01011       static const _Tp&
01012       _S_cget(const _Hashtable_ebo_helper& __eboh)
01013       { return __eboh._M_tp; }
01014 
01015       static _Tp&
01016       _S_get(_Hashtable_ebo_helper& __eboh)
01017       { return __eboh._M_tp; }
01018 
01019     private:
01020       _Tp _M_tp;
01021     };
01022 
01023   /**
01024    *  Primary class template _Local_iterator_base.
01025    *
01026    *  Base class for local iterators, used to iterate within a bucket
01027    *  but not between buckets.
01028    */
01029   template<typename _Key, typename _Value, typename _ExtractKey,
01030        typename _H1, typename _H2, typename _Hash,
01031        bool __cache_hash_code>
01032     struct _Local_iterator_base;
01033 
01034   /**
01035    *  Primary class template _Hash_code_base.
01036    *
01037    *  Encapsulates two policy issues that aren't quite orthogonal.
01038    *   (1) the difference between using a ranged hash function and using
01039    *       the combination of a hash function and a range-hashing function.
01040    *       In the former case we don't have such things as hash codes, so
01041    *       we have a dummy type as placeholder.
01042    *   (2) Whether or not we cache hash codes.  Caching hash codes is
01043    *       meaningless if we have a ranged hash function.
01044    *
01045    *  We also put the key extraction objects here, for convenience.
01046    *  Each specialization derives from one or more of the template
01047    *  parameters to benefit from Ebo. This is important as this type
01048    *  is inherited in some cases by the _Local_iterator_base type used
01049    *  to implement local_iterator and const_local_iterator. As with
01050    *  any iterator type we prefer to make it as small as possible.
01051    *
01052    *  Primary template is unused except as a hook for specializations.
01053    */
01054   template<typename _Key, typename _Value, typename _ExtractKey,
01055        typename _H1, typename _H2, typename _Hash,
01056        bool __cache_hash_code>
01057     struct _Hash_code_base;
01058 
01059   /// Specialization: ranged hash function, no caching hash codes.  H1
01060   /// and H2 are provided but ignored.  We define a dummy hash code type.
01061   template<typename _Key, typename _Value, typename _ExtractKey,
01062        typename _H1, typename _H2, typename _Hash>
01063     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, false>
01064     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01065       private _Hashtable_ebo_helper<1, _Hash>
01066     {
01067     private:
01068       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01069       using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
01070 
01071     protected:
01072       typedef void*                     __hash_code;
01073       typedef _Hash_node<_Value, false>         __node_type;
01074 
01075       // We need the default constructor for the local iterators.
01076       _Hash_code_base() = default;
01077 
01078       _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,
01079               const _Hash& __h)
01080       : __ebo_extract_key(__ex), __ebo_hash(__h) { }
01081 
01082       __hash_code
01083       _M_hash_code(const _Key& __key) const
01084       { return 0; }
01085 
01086       std::size_t
01087       _M_bucket_index(const _Key& __k, __hash_code, std::size_t __n) const
01088       { return _M_ranged_hash()(__k, __n); }
01089 
01090       std::size_t
01091       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01092     noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>(),
01093                            (std::size_t)0)) )
01094       { return _M_ranged_hash()(_M_extract()(__p->_M_v()), __n); }
01095 
01096       void
01097       _M_store_code(__node_type*, __hash_code) const
01098       { }
01099 
01100       void
01101       _M_copy_code(__node_type*, const __node_type*) const
01102       { }
01103 
01104       void
01105       _M_swap(_Hash_code_base& __x)
01106       {
01107     std::swap(_M_extract(), __x._M_extract());
01108     std::swap(_M_ranged_hash(), __x._M_ranged_hash());
01109       }
01110 
01111       const _ExtractKey&
01112       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01113 
01114       _ExtractKey&
01115       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01116 
01117       const _Hash&
01118       _M_ranged_hash() const { return __ebo_hash::_S_cget(*this); }
01119 
01120       _Hash&
01121       _M_ranged_hash() { return __ebo_hash::_S_get(*this); }
01122     };
01123 
01124   // No specialization for ranged hash function while caching hash codes.
01125   // That combination is meaningless, and trying to do it is an error.
01126 
01127   /// Specialization: ranged hash function, cache hash codes.  This
01128   /// combination is meaningless, so we provide only a declaration
01129   /// and no definition.
01130   template<typename _Key, typename _Value, typename _ExtractKey,
01131        typename _H1, typename _H2, typename _Hash>
01132     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, true>;
01133 
01134   /// Specialization: hash function and range-hashing function, no
01135   /// caching of hash codes.
01136   /// Provides typedef and accessor required by C++ 11.
01137   template<typename _Key, typename _Value, typename _ExtractKey,
01138        typename _H1, typename _H2>
01139     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
01140                _Default_ranged_hash, false>
01141     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01142       private _Hashtable_ebo_helper<1, _H1>,
01143       private _Hashtable_ebo_helper<2, _H2>
01144     {
01145     private:
01146       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01147       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
01148       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
01149 
01150       // Gives the local iterator implementation access to _M_bucket_index().
01151       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
01152                      _Default_ranged_hash, false>;
01153 
01154     public:
01155       typedef _H1                   hasher;
01156 
01157       hasher
01158       hash_function() const
01159       { return _M_h1(); }
01160 
01161     protected:
01162       typedef std::size_t               __hash_code;
01163       typedef _Hash_node<_Value, false>         __node_type;
01164 
01165       // We need the default constructor for the local iterators.
01166       _Hash_code_base() = default;
01167 
01168       _Hash_code_base(const _ExtractKey& __ex,
01169               const _H1& __h1, const _H2& __h2,
01170               const _Default_ranged_hash&)
01171       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
01172 
01173       __hash_code
01174       _M_hash_code(const _Key& __k) const
01175       { return _M_h1()(__k); }
01176 
01177       std::size_t
01178       _M_bucket_index(const _Key&, __hash_code __c, std::size_t __n) const
01179       { return _M_h2()(__c, __n); }
01180 
01181       std::size_t
01182       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01183     noexcept( noexcept(declval<const _H1&>()(declval<const _Key&>()))
01184           && noexcept(declval<const _H2&>()((__hash_code)0,
01185                             (std::size_t)0)) )
01186       { return _M_h2()(_M_h1()(_M_extract()(__p->_M_v())), __n); }
01187 
01188       void
01189       _M_store_code(__node_type*, __hash_code) const
01190       { }
01191 
01192       void
01193       _M_copy_code(__node_type*, const __node_type*) const
01194       { }
01195 
01196       void
01197       _M_swap(_Hash_code_base& __x)
01198       {
01199     std::swap(_M_extract(), __x._M_extract());
01200     std::swap(_M_h1(), __x._M_h1());
01201     std::swap(_M_h2(), __x._M_h2());
01202       }
01203 
01204       const _ExtractKey&
01205       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01206 
01207       _ExtractKey&
01208       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01209 
01210       const _H1&
01211       _M_h1() const { return __ebo_h1::_S_cget(*this); }
01212 
01213       _H1&
01214       _M_h1() { return __ebo_h1::_S_get(*this); }
01215 
01216       const _H2&
01217       _M_h2() const { return __ebo_h2::_S_cget(*this); }
01218 
01219       _H2&
01220       _M_h2() { return __ebo_h2::_S_get(*this); }
01221     };
01222 
01223   /// Specialization: hash function and range-hashing function,
01224   /// caching hash codes.  H is provided but ignored.  Provides
01225   /// typedef and accessor required by C++ 11.
01226   template<typename _Key, typename _Value, typename _ExtractKey,
01227        typename _H1, typename _H2>
01228     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
01229                _Default_ranged_hash, true>
01230     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01231       private _Hashtable_ebo_helper<1, _H1>,
01232       private _Hashtable_ebo_helper<2, _H2>
01233     {
01234     private:
01235       // Gives the local iterator implementation access to _M_h2().
01236       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
01237                      _Default_ranged_hash, true>;
01238 
01239       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01240       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
01241       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
01242 
01243     public:
01244       typedef _H1                   hasher;
01245 
01246       hasher
01247       hash_function() const
01248       { return _M_h1(); }
01249 
01250     protected:
01251       typedef std::size_t               __hash_code;
01252       typedef _Hash_node<_Value, true>          __node_type;
01253 
01254       _Hash_code_base(const _ExtractKey& __ex,
01255               const _H1& __h1, const _H2& __h2,
01256               const _Default_ranged_hash&)
01257       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
01258 
01259       __hash_code
01260       _M_hash_code(const _Key& __k) const
01261       { return _M_h1()(__k); }
01262 
01263       std::size_t
01264       _M_bucket_index(const _Key&, __hash_code __c,
01265               std::size_t __n) const
01266       { return _M_h2()(__c, __n); }
01267 
01268       std::size_t
01269       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01270     noexcept( noexcept(declval<const _H2&>()((__hash_code)0,
01271                          (std::size_t)0)) )
01272       { return _M_h2()(__p->_M_hash_code, __n); }
01273 
01274       void
01275       _M_store_code(__node_type* __n, __hash_code __c) const
01276       { __n->_M_hash_code = __c; }
01277 
01278       void
01279       _M_copy_code(__node_type* __to, const __node_type* __from) const
01280       { __to->_M_hash_code = __from->_M_hash_code; }
01281 
01282       void
01283       _M_swap(_Hash_code_base& __x)
01284       {
01285     std::swap(_M_extract(), __x._M_extract());
01286     std::swap(_M_h1(), __x._M_h1());
01287     std::swap(_M_h2(), __x._M_h2());
01288       }
01289 
01290       const _ExtractKey&
01291       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01292 
01293       _ExtractKey&
01294       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01295 
01296       const _H1&
01297       _M_h1() const { return __ebo_h1::_S_cget(*this); }
01298 
01299       _H1&
01300       _M_h1() { return __ebo_h1::_S_get(*this); }
01301 
01302       const _H2&
01303       _M_h2() const { return __ebo_h2::_S_cget(*this); }
01304 
01305       _H2&
01306       _M_h2() { return __ebo_h2::_S_get(*this); }
01307     };
01308 
01309   /**
01310    *  Primary class template _Equal_helper.
01311    *
01312    */
01313   template <typename _Key, typename _Value, typename _ExtractKey,
01314         typename _Equal, typename _HashCodeType,
01315         bool __cache_hash_code>
01316   struct _Equal_helper;
01317 
01318   /// Specialization.
01319   template<typename _Key, typename _Value, typename _ExtractKey,
01320        typename _Equal, typename _HashCodeType>
01321   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, true>
01322   {
01323     static bool
01324     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
01325           const _Key& __k, _HashCodeType __c, _Hash_node<_Value, true>* __n)
01326     { return __c == __n->_M_hash_code && __eq(__k, __extract(__n->_M_v())); }
01327   };
01328 
01329   /// Specialization.
01330   template<typename _Key, typename _Value, typename _ExtractKey,
01331        typename _Equal, typename _HashCodeType>
01332   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, false>
01333   {
01334     static bool
01335     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
01336           const _Key& __k, _HashCodeType, _Hash_node<_Value, false>* __n)
01337     { return __eq(__k, __extract(__n->_M_v())); }
01338   };
01339 
01340 
01341   /// Partial specialization used when nodes contain a cached hash code.
01342   template<typename _Key, typename _Value, typename _ExtractKey,
01343        typename _H1, typename _H2, typename _Hash>
01344     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
01345                 _H1, _H2, _Hash, true>
01346     : private _Hashtable_ebo_helper<0, _H2>
01347     {
01348     protected:
01349       using __base_type = _Hashtable_ebo_helper<0, _H2>;
01350       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01351                            _H1, _H2, _Hash, true>;
01352 
01353       _Local_iterator_base() = default;
01354       _Local_iterator_base(const __hash_code_base& __base,
01355                _Hash_node<_Value, true>* __p,
01356                std::size_t __bkt, std::size_t __bkt_count)
01357       : __base_type(__base._M_h2()),
01358     _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count) { }
01359 
01360       void
01361       _M_incr()
01362       {
01363     _M_cur = _M_cur->_M_next();
01364     if (_M_cur)
01365       {
01366         std::size_t __bkt
01367           = __base_type::_S_get(*this)(_M_cur->_M_hash_code,
01368                        _M_bucket_count);
01369         if (__bkt != _M_bucket)
01370           _M_cur = nullptr;
01371       }
01372       }
01373 
01374       _Hash_node<_Value, true>*  _M_cur;
01375       std::size_t _M_bucket;
01376       std::size_t _M_bucket_count;
01377 
01378     public:
01379       const void*
01380       _M_curr() const { return _M_cur; }  // for equality ops
01381 
01382       std::size_t
01383       _M_get_bucket() const { return _M_bucket; }  // for debug mode
01384     };
01385 
01386   // Uninitialized storage for a _Hash_code_base.
01387   // This type is DefaultConstructible and Assignable even if the
01388   // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
01389   // can be DefaultConstructible and Assignable.
01390   template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
01391     struct _Hash_code_storage
01392     {
01393       __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
01394 
01395       _Tp*
01396       _M_h() { return _M_storage._M_ptr(); }
01397 
01398       const _Tp*
01399       _M_h() const { return _M_storage._M_ptr(); }
01400     };
01401 
01402   // Empty partial specialization for empty _Hash_code_base types.
01403   template<typename _Tp>
01404     struct _Hash_code_storage<_Tp, true>
01405     {
01406       static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
01407 
01408       // As _Tp is an empty type there will be no bytes written/read through
01409       // the cast pointer, so no strict-aliasing violation.
01410       _Tp*
01411       _M_h() { return reinterpret_cast<_Tp*>(this); }
01412 
01413       const _Tp*
01414       _M_h() const { return reinterpret_cast<const _Tp*>(this); }
01415     };
01416 
01417   template<typename _Key, typename _Value, typename _ExtractKey,
01418        typename _H1, typename _H2, typename _Hash>
01419     using __hash_code_for_local_iter
01420       = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
01421                        _H1, _H2, _Hash, false>>;
01422 
01423   // Partial specialization used when hash codes are not cached
01424   template<typename _Key, typename _Value, typename _ExtractKey,
01425        typename _H1, typename _H2, typename _Hash>
01426     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
01427                 _H1, _H2, _Hash, false>
01428     : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _H1, _H2, _Hash>
01429     {
01430     protected:
01431       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01432                            _H1, _H2, _Hash, false>;
01433 
01434       _Local_iterator_base() : _M_bucket_count(-1) { }
01435 
01436       _Local_iterator_base(const __hash_code_base& __base,
01437                _Hash_node<_Value, false>* __p,
01438                std::size_t __bkt, std::size_t __bkt_count)
01439       : _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
01440       { _M_init(__base); }
01441 
01442       ~_Local_iterator_base()
01443       {
01444     if (_M_bucket_count != -1)
01445       _M_destroy();
01446       }
01447 
01448       _Local_iterator_base(const _Local_iterator_base& __iter)
01449       : _M_cur(__iter._M_cur), _M_bucket(__iter._M_bucket),
01450         _M_bucket_count(__iter._M_bucket_count)
01451       {
01452     if (_M_bucket_count != -1)
01453       _M_init(*__iter._M_h());
01454       }
01455 
01456       _Local_iterator_base&
01457       operator=(const _Local_iterator_base& __iter)
01458       {
01459     if (_M_bucket_count != -1)
01460       _M_destroy();
01461     _M_cur = __iter._M_cur;
01462     _M_bucket = __iter._M_bucket;
01463     _M_bucket_count = __iter._M_bucket_count;
01464     if (_M_bucket_count != -1)
01465       _M_init(*__iter._M_h());
01466     return *this;
01467       }
01468 
01469       void
01470       _M_incr()
01471       {
01472     _M_cur = _M_cur->_M_next();
01473     if (_M_cur)
01474       {
01475         std::size_t __bkt = this->_M_h()->_M_bucket_index(_M_cur,
01476                                   _M_bucket_count);
01477         if (__bkt != _M_bucket)
01478           _M_cur = nullptr;
01479       }
01480       }
01481 
01482       _Hash_node<_Value, false>*  _M_cur;
01483       std::size_t _M_bucket;
01484       std::size_t _M_bucket_count;
01485 
01486       void
01487       _M_init(const __hash_code_base& __base)
01488       { ::new(this->_M_h()) __hash_code_base(__base); }
01489 
01490       void
01491       _M_destroy() { this->_M_h()->~__hash_code_base(); }
01492 
01493     public:
01494       const void*
01495       _M_curr() const { return _M_cur; }  // for equality ops and debug mode
01496 
01497       std::size_t
01498       _M_get_bucket() const { return _M_bucket; }  // for debug mode
01499     };
01500 
01501   template<typename _Key, typename _Value, typename _ExtractKey,
01502        typename _H1, typename _H2, typename _Hash, bool __cache>
01503     inline bool
01504     operator==(const _Local_iterator_base<_Key, _Value, _ExtractKey,
01505                       _H1, _H2, _Hash, __cache>& __x,
01506            const _Local_iterator_base<_Key, _Value, _ExtractKey,
01507                       _H1, _H2, _Hash, __cache>& __y)
01508     { return __x._M_curr() == __y._M_curr(); }
01509 
01510   template<typename _Key, typename _Value, typename _ExtractKey,
01511        typename _H1, typename _H2, typename _Hash, bool __cache>
01512     inline bool
01513     operator!=(const _Local_iterator_base<_Key, _Value, _ExtractKey,
01514                       _H1, _H2, _Hash, __cache>& __x,
01515            const _Local_iterator_base<_Key, _Value, _ExtractKey,
01516                       _H1, _H2, _Hash, __cache>& __y)
01517     { return __x._M_curr() != __y._M_curr(); }
01518 
01519   /// local iterators
01520   template<typename _Key, typename _Value, typename _ExtractKey,
01521        typename _H1, typename _H2, typename _Hash,
01522        bool __constant_iterators, bool __cache>
01523     struct _Local_iterator
01524     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
01525                   _H1, _H2, _Hash, __cache>
01526     {
01527     private:
01528       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
01529                            _H1, _H2, _Hash, __cache>;
01530       using __hash_code_base = typename __base_type::__hash_code_base;
01531     public:
01532       typedef _Value                    value_type;
01533       typedef typename std::conditional<__constant_iterators,
01534                     const _Value*, _Value*>::type
01535                                pointer;
01536       typedef typename std::conditional<__constant_iterators,
01537                     const _Value&, _Value&>::type
01538                                reference;
01539       typedef std::ptrdiff_t                difference_type;
01540       typedef std::forward_iterator_tag         iterator_category;
01541 
01542       _Local_iterator() = default;
01543 
01544       _Local_iterator(const __hash_code_base& __base,
01545               _Hash_node<_Value, __cache>* __p,
01546               std::size_t __bkt, std::size_t __bkt_count)
01547     : __base_type(__base, __p, __bkt, __bkt_count)
01548       { }
01549 
01550       reference
01551       operator*() const
01552       { return this->_M_cur->_M_v(); }
01553 
01554       pointer
01555       operator->() const
01556       { return this->_M_cur->_M_valptr(); }
01557 
01558       _Local_iterator&
01559       operator++()
01560       {
01561     this->_M_incr();
01562     return *this;
01563       }
01564 
01565       _Local_iterator
01566       operator++(int)
01567       {
01568     _Local_iterator __tmp(*this);
01569     this->_M_incr();
01570     return __tmp;
01571       }
01572     };
01573 
01574   /// local const_iterators
01575   template<typename _Key, typename _Value, typename _ExtractKey,
01576        typename _H1, typename _H2, typename _Hash,
01577        bool __constant_iterators, bool __cache>
01578     struct _Local_const_iterator
01579     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
01580                   _H1, _H2, _Hash, __cache>
01581     {
01582     private:
01583       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
01584                            _H1, _H2, _Hash, __cache>;
01585       using __hash_code_base = typename __base_type::__hash_code_base;
01586 
01587     public:
01588       typedef _Value                    value_type;
01589       typedef const _Value*             pointer;
01590       typedef const _Value&             reference;
01591       typedef std::ptrdiff_t                difference_type;
01592       typedef std::forward_iterator_tag         iterator_category;
01593 
01594       _Local_const_iterator() = default;
01595 
01596       _Local_const_iterator(const __hash_code_base& __base,
01597                 _Hash_node<_Value, __cache>* __p,
01598                 std::size_t __bkt, std::size_t __bkt_count)
01599     : __base_type(__base, __p, __bkt, __bkt_count)
01600       { }
01601 
01602       _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
01603                           _H1, _H2, _Hash,
01604                           __constant_iterators,
01605                           __cache>& __x)
01606     : __base_type(__x)
01607       { }
01608 
01609       reference
01610       operator*() const
01611       { return this->_M_cur->_M_v(); }
01612 
01613       pointer
01614       operator->() const
01615       { return this->_M_cur->_M_valptr(); }
01616 
01617       _Local_const_iterator&
01618       operator++()
01619       {
01620     this->_M_incr();
01621     return *this;
01622       }
01623 
01624       _Local_const_iterator
01625       operator++(int)
01626       {
01627     _Local_const_iterator __tmp(*this);
01628     this->_M_incr();
01629     return __tmp;
01630       }
01631     };
01632 
01633   /**
01634    *  Primary class template _Hashtable_base.
01635    *
01636    *  Helper class adding management of _Equal functor to
01637    *  _Hash_code_base type.
01638    *
01639    *  Base class templates are:
01640    *    - __detail::_Hash_code_base
01641    *    - __detail::_Hashtable_ebo_helper
01642    */
01643   template<typename _Key, typename _Value,
01644        typename _ExtractKey, typename _Equal,
01645        typename _H1, typename _H2, typename _Hash, typename _Traits>
01646   struct _Hashtable_base
01647   : public _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash,
01648                _Traits::__hash_cached::value>,
01649     private _Hashtable_ebo_helper<0, _Equal>
01650   {
01651   public:
01652     typedef _Key                    key_type;
01653     typedef _Value                  value_type;
01654     typedef _Equal                  key_equal;
01655     typedef std::size_t                 size_type;
01656     typedef std::ptrdiff_t              difference_type;
01657 
01658     using __traits_type = _Traits;
01659     using __hash_cached = typename __traits_type::__hash_cached;
01660     using __constant_iterators = typename __traits_type::__constant_iterators;
01661     using __unique_keys = typename __traits_type::__unique_keys;
01662 
01663     using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01664                          _H1, _H2, _Hash,
01665                          __hash_cached::value>;
01666 
01667     using __hash_code = typename __hash_code_base::__hash_code;
01668     using __node_type = typename __hash_code_base::__node_type;
01669 
01670     using iterator = __detail::_Node_iterator<value_type,
01671                           __constant_iterators::value,
01672                           __hash_cached::value>;
01673 
01674     using const_iterator = __detail::_Node_const_iterator<value_type,
01675                            __constant_iterators::value,
01676                            __hash_cached::value>;
01677 
01678     using local_iterator = __detail::_Local_iterator<key_type, value_type,
01679                           _ExtractKey, _H1, _H2, _Hash,
01680                           __constant_iterators::value,
01681                              __hash_cached::value>;
01682 
01683     using const_local_iterator = __detail::_Local_const_iterator<key_type,
01684                                  value_type,
01685                     _ExtractKey, _H1, _H2, _Hash,
01686                     __constant_iterators::value,
01687                     __hash_cached::value>;
01688 
01689     using __ireturn_type = typename std::conditional<__unique_keys::value,
01690                              std::pair<iterator, bool>,
01691                              iterator>::type;
01692   private:
01693     using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
01694     using _EqualHelper =  _Equal_helper<_Key, _Value, _ExtractKey, _Equal,
01695                     __hash_code, __hash_cached::value>;
01696 
01697   protected:
01698     _Hashtable_base(const _ExtractKey& __ex, const _H1& __h1, const _H2& __h2,
01699             const _Hash& __hash, const _Equal& __eq)
01700     : __hash_code_base(__ex, __h1, __h2, __hash), _EqualEBO(__eq)
01701     { }
01702 
01703     bool
01704     _M_equals(const _Key& __k, __hash_code __c, __node_type* __n) const
01705     {
01706       return _EqualHelper::_S_equals(_M_eq(), this->_M_extract(),
01707                      __k, __c, __n);
01708     }
01709 
01710     void
01711     _M_swap(_Hashtable_base& __x)
01712     {
01713       __hash_code_base::_M_swap(__x);
01714       std::swap(_M_eq(), __x._M_eq());
01715     }
01716 
01717     const _Equal&
01718     _M_eq() const { return _EqualEBO::_S_cget(*this); }
01719 
01720     _Equal&
01721     _M_eq() { return _EqualEBO::_S_get(*this); }
01722   };
01723 
01724   /**
01725    *  struct _Equality_base.
01726    *
01727    *  Common types and functions for class _Equality.
01728    */
01729   struct _Equality_base
01730   {
01731   protected:
01732     template<typename _Uiterator>
01733       static bool
01734       _S_is_permutation(_Uiterator, _Uiterator, _Uiterator);
01735   };
01736 
01737   // See std::is_permutation in N3068.
01738   template<typename _Uiterator>
01739     bool
01740     _Equality_base::
01741     _S_is_permutation(_Uiterator __first1, _Uiterator __last1,
01742               _Uiterator __first2)
01743     {
01744       for (; __first1 != __last1; ++__first1, ++__first2)
01745     if (!(*__first1 == *__first2))
01746       break;
01747 
01748       if (__first1 == __last1)
01749     return true;
01750 
01751       _Uiterator __last2 = __first2;
01752       std::advance(__last2, std::distance(__first1, __last1));
01753 
01754       for (_Uiterator __it1 = __first1; __it1 != __last1; ++__it1)
01755     {
01756       _Uiterator __tmp =  __first1;
01757       while (__tmp != __it1 && !bool(*__tmp == *__it1))
01758         ++__tmp;
01759 
01760       // We've seen this one before.
01761       if (__tmp != __it1)
01762         continue;
01763 
01764       std::ptrdiff_t __n2 = 0;
01765       for (__tmp = __first2; __tmp != __last2; ++__tmp)
01766         if (*__tmp == *__it1)
01767           ++__n2;
01768 
01769       if (!__n2)
01770         return false;
01771 
01772       std::ptrdiff_t __n1 = 0;
01773       for (__tmp = __it1; __tmp != __last1; ++__tmp)
01774         if (*__tmp == *__it1)
01775           ++__n1;
01776 
01777       if (__n1 != __n2)
01778         return false;
01779     }
01780       return true;
01781     }
01782 
01783   /**
01784    *  Primary class template  _Equality.
01785    *
01786    *  This is for implementing equality comparison for unordered
01787    *  containers, per N3068, by John Lakos and Pablo Halpern.
01788    *  Algorithmically, we follow closely the reference implementations
01789    *  therein.
01790    */
01791   template<typename _Key, typename _Value, typename _Alloc,
01792        typename _ExtractKey, typename _Equal,
01793        typename _H1, typename _H2, typename _Hash,
01794        typename _RehashPolicy, typename _Traits,
01795        bool _Unique_keys = _Traits::__unique_keys::value>
01796     struct _Equality;
01797 
01798   /// Specialization.
01799   template<typename _Key, typename _Value, typename _Alloc,
01800        typename _ExtractKey, typename _Equal,
01801        typename _H1, typename _H2, typename _Hash,
01802        typename _RehashPolicy, typename _Traits>
01803     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01804              _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
01805     {
01806       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01807                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
01808 
01809       bool
01810       _M_equal(const __hashtable&) const;
01811     };
01812 
01813   template<typename _Key, typename _Value, typename _Alloc,
01814        typename _ExtractKey, typename _Equal,
01815        typename _H1, typename _H2, typename _Hash,
01816        typename _RehashPolicy, typename _Traits>
01817     bool
01818     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01819           _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
01820     _M_equal(const __hashtable& __other) const
01821     {
01822       const __hashtable* __this = static_cast<const __hashtable*>(this);
01823 
01824       if (__this->size() != __other.size())
01825     return false;
01826 
01827       for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
01828     {
01829       const auto __ity = __other.find(_ExtractKey()(*__itx));
01830       if (__ity == __other.end() || !bool(*__ity == *__itx))
01831         return false;
01832     }
01833       return true;
01834     }
01835 
01836   /// Specialization.
01837   template<typename _Key, typename _Value, typename _Alloc,
01838        typename _ExtractKey, typename _Equal,
01839        typename _H1, typename _H2, typename _Hash,
01840        typename _RehashPolicy, typename _Traits>
01841     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01842              _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
01843     : public _Equality_base
01844     {
01845       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01846                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
01847 
01848       bool
01849       _M_equal(const __hashtable&) const;
01850     };
01851 
01852   template<typename _Key, typename _Value, typename _Alloc,
01853        typename _ExtractKey, typename _Equal,
01854        typename _H1, typename _H2, typename _Hash,
01855        typename _RehashPolicy, typename _Traits>
01856     bool
01857     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01858           _H1, _H2, _Hash, _RehashPolicy, _Traits, false>::
01859     _M_equal(const __hashtable& __other) const
01860     {
01861       const __hashtable* __this = static_cast<const __hashtable*>(this);
01862 
01863       if (__this->size() != __other.size())
01864     return false;
01865 
01866       for (auto __itx = __this->begin(); __itx != __this->end();)
01867     {
01868       const auto __xrange = __this->equal_range(_ExtractKey()(*__itx));
01869       const auto __yrange = __other.equal_range(_ExtractKey()(*__itx));
01870 
01871       if (std::distance(__xrange.first, __xrange.second)
01872           != std::distance(__yrange.first, __yrange.second))
01873         return false;
01874 
01875       if (!_S_is_permutation(__xrange.first, __xrange.second,
01876                  __yrange.first))
01877         return false;
01878 
01879       __itx = __xrange.second;
01880     }
01881       return true;
01882     }
01883 
01884   /**
01885    * This type deals with all allocation and keeps an allocator instance through
01886    * inheritance to benefit from EBO when possible.
01887    */
01888   template<typename _NodeAlloc>
01889     struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
01890     {
01891     private:
01892       using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
01893     public:
01894       using __node_type = typename _NodeAlloc::value_type;
01895       using __node_alloc_type = _NodeAlloc;
01896       // Use __gnu_cxx to benefit from _S_always_equal and al.
01897       using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
01898 
01899       using __value_type = typename __node_type::value_type;
01900       using __value_alloc_type =
01901     typename __alloctr_rebind<__node_alloc_type, __value_type>::__type;
01902       using __value_alloc_traits = std::allocator_traits<__value_alloc_type>;
01903 
01904       using __node_base = __detail::_Hash_node_base;
01905       using __bucket_type = __node_base*;      
01906       using __bucket_alloc_type =
01907     typename __alloctr_rebind<__node_alloc_type, __bucket_type>::__type;
01908       using __bucket_alloc_traits = std::allocator_traits<__bucket_alloc_type>;
01909 
01910       _Hashtable_alloc(const _Hashtable_alloc&) = default;
01911       _Hashtable_alloc(_Hashtable_alloc&&) = default;
01912 
01913       template<typename _Alloc>
01914     _Hashtable_alloc(_Alloc&& __a)
01915       : __ebo_node_alloc(std::forward<_Alloc>(__a))
01916     { }
01917 
01918       __node_alloc_type&
01919       _M_node_allocator()
01920       { return __ebo_node_alloc::_S_get(*this); }
01921 
01922       const __node_alloc_type&
01923       _M_node_allocator() const
01924       { return __ebo_node_alloc::_S_cget(*this); }
01925 
01926       template<typename... _Args>
01927     __node_type*
01928     _M_allocate_node(_Args&&... __args);
01929 
01930       void
01931       _M_deallocate_node(__node_type* __n);
01932 
01933       // Deallocate the linked list of nodes pointed to by __n
01934       void
01935       _M_deallocate_nodes(__node_type* __n);
01936 
01937       __bucket_type*
01938       _M_allocate_buckets(std::size_t __n);
01939 
01940       void
01941       _M_deallocate_buckets(__bucket_type*, std::size_t __n);
01942     };
01943 
01944   // Definitions of class template _Hashtable_alloc's out-of-line member
01945   // functions.
01946   template<typename _NodeAlloc>
01947     template<typename... _Args>
01948       typename _Hashtable_alloc<_NodeAlloc>::__node_type*
01949       _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
01950       {
01951     auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
01952     __node_type* __n = std::__addressof(*__nptr);
01953     __try
01954       {
01955         __value_alloc_type __a(_M_node_allocator());
01956         ::new ((void*)__n) __node_type;
01957         __value_alloc_traits::construct(__a, __n->_M_valptr(),
01958                         std::forward<_Args>(__args)...);
01959         return __n;
01960       }
01961     __catch(...)
01962       {
01963         __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
01964         __throw_exception_again;
01965       }
01966       }
01967 
01968   template<typename _NodeAlloc>
01969     void
01970     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_type* __n)
01971     {
01972       typedef typename __node_alloc_traits::pointer _Ptr;
01973       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
01974       __value_alloc_type __a(_M_node_allocator());
01975       __value_alloc_traits::destroy(__a, __n->_M_valptr());
01976       __n->~__node_type();
01977       __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
01978     }
01979 
01980   template<typename _NodeAlloc>
01981     void
01982     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_type* __n)
01983     {
01984       while (__n)
01985     {
01986       __node_type* __tmp = __n;
01987       __n = __n->_M_next();
01988       _M_deallocate_node(__tmp);
01989     }
01990     }
01991 
01992   template<typename _NodeAlloc>
01993     typename _Hashtable_alloc<_NodeAlloc>::__bucket_type*
01994     _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __n)
01995     {
01996       __bucket_alloc_type __alloc(_M_node_allocator());
01997 
01998       auto __ptr = __bucket_alloc_traits::allocate(__alloc, __n);
01999       __bucket_type* __p = std::__addressof(*__ptr);
02000       __builtin_memset(__p, 0, __n * sizeof(__bucket_type));
02001       return __p;
02002     }
02003 
02004   template<typename _NodeAlloc>
02005     void
02006     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_buckets(__bucket_type* __bkts,
02007                             std::size_t __n)
02008     {
02009       typedef typename __bucket_alloc_traits::pointer _Ptr;
02010       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
02011       __bucket_alloc_type __alloc(_M_node_allocator());
02012       __bucket_alloc_traits::deallocate(__alloc, __ptr, __n);
02013     }
02014 
02015  //@} hashtable-detail
02016 _GLIBCXX_END_NAMESPACE_VERSION
02017 } // namespace __detail
02018 } // namespace std
02019 
02020 #endif // _HASHTABLE_POLICY_H