libstdc++
hashtable_policy.h
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00001 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
00002 
00003 // Copyright (C) 2010-2016 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::__bool_constant<
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       using __hash_cached = __bool_constant<_Cache_hash_code>;
00215       using __constant_iterators = __bool_constant<_Constant_iterators>;
00216       using __unique_keys = __bool_constant<_Unique_keys>;
00217     };
00218 
00219   /**
00220    *  struct _Hash_node_base
00221    *
00222    *  Nodes, used to wrap elements stored in the hash table.  A policy
00223    *  template parameter of class template _Hashtable controls whether
00224    *  nodes also store a hash code. In some cases (e.g. strings) this
00225    *  may be a performance win.
00226    */
00227   struct _Hash_node_base
00228   {
00229     _Hash_node_base* _M_nxt;
00230 
00231     _Hash_node_base() noexcept : _M_nxt() { }
00232 
00233     _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
00234   };
00235 
00236   /**
00237    *  struct _Hash_node_value_base
00238    *
00239    *  Node type with the value to store.
00240    */
00241   template<typename _Value>
00242     struct _Hash_node_value_base : _Hash_node_base
00243     {
00244       typedef _Value value_type;
00245 
00246       __gnu_cxx::__aligned_buffer<_Value> _M_storage;
00247 
00248       _Value*
00249       _M_valptr() noexcept
00250       { return _M_storage._M_ptr(); }
00251 
00252       const _Value*
00253       _M_valptr() const noexcept
00254       { return _M_storage._M_ptr(); }
00255 
00256       _Value&
00257       _M_v() noexcept
00258       { return *_M_valptr(); }
00259 
00260       const _Value&
00261       _M_v() const noexcept
00262       { return *_M_valptr(); }
00263     };
00264 
00265   /**
00266    *  Primary template struct _Hash_node.
00267    */
00268   template<typename _Value, bool _Cache_hash_code>
00269     struct _Hash_node;
00270 
00271   /**
00272    *  Specialization for nodes with caches, struct _Hash_node.
00273    *
00274    *  Base class is __detail::_Hash_node_value_base.
00275    */
00276   template<typename _Value>
00277     struct _Hash_node<_Value, true> : _Hash_node_value_base<_Value>
00278     {
00279       std::size_t  _M_hash_code;
00280 
00281       _Hash_node*
00282       _M_next() const noexcept
00283       { return static_cast<_Hash_node*>(this->_M_nxt); }
00284     };
00285 
00286   /**
00287    *  Specialization for nodes without caches, struct _Hash_node.
00288    *
00289    *  Base class is __detail::_Hash_node_value_base.
00290    */
00291   template<typename _Value>
00292     struct _Hash_node<_Value, false> : _Hash_node_value_base<_Value>
00293     {
00294       _Hash_node*
00295       _M_next() const noexcept
00296       { return static_cast<_Hash_node*>(this->_M_nxt); }
00297     };
00298 
00299   /// Base class for node iterators.
00300   template<typename _Value, bool _Cache_hash_code>
00301     struct _Node_iterator_base
00302     {
00303       using __node_type = _Hash_node<_Value, _Cache_hash_code>;
00304 
00305       __node_type*  _M_cur;
00306 
00307       _Node_iterator_base(__node_type* __p) noexcept
00308       : _M_cur(__p) { }
00309 
00310       void
00311       _M_incr() noexcept
00312       { _M_cur = _M_cur->_M_next(); }
00313     };
00314 
00315   template<typename _Value, bool _Cache_hash_code>
00316     inline bool
00317     operator==(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
00318                const _Node_iterator_base<_Value, _Cache_hash_code >& __y)
00319     noexcept
00320     { return __x._M_cur == __y._M_cur; }
00321 
00322   template<typename _Value, bool _Cache_hash_code>
00323     inline bool
00324     operator!=(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
00325                const _Node_iterator_base<_Value, _Cache_hash_code>& __y)
00326     noexcept
00327     { return __x._M_cur != __y._M_cur; }
00328 
00329   /// Node iterators, used to iterate through all the hashtable.
00330   template<typename _Value, bool __constant_iterators, bool __cache>
00331     struct _Node_iterator
00332     : public _Node_iterator_base<_Value, __cache>
00333     {
00334     private:
00335       using __base_type = _Node_iterator_base<_Value, __cache>;
00336       using __node_type = typename __base_type::__node_type;
00337 
00338     public:
00339       typedef _Value                                    value_type;
00340       typedef std::ptrdiff_t                            difference_type;
00341       typedef std::forward_iterator_tag                 iterator_category;
00342 
00343       using pointer = typename std::conditional<__constant_iterators,
00344                                                 const _Value*, _Value*>::type;
00345 
00346       using reference = typename std::conditional<__constant_iterators,
00347                                                   const _Value&, _Value&>::type;
00348 
00349       _Node_iterator() noexcept
00350       : __base_type(0) { }
00351 
00352       explicit
00353       _Node_iterator(__node_type* __p) noexcept
00354       : __base_type(__p) { }
00355 
00356       reference
00357       operator*() const noexcept
00358       { return this->_M_cur->_M_v(); }
00359 
00360       pointer
00361       operator->() const noexcept
00362       { return this->_M_cur->_M_valptr(); }
00363 
00364       _Node_iterator&
00365       operator++() noexcept
00366       {
00367         this->_M_incr();
00368         return *this;
00369       }
00370 
00371       _Node_iterator
00372       operator++(int) noexcept
00373       {
00374         _Node_iterator __tmp(*this);
00375         this->_M_incr();
00376         return __tmp;
00377       }
00378     };
00379 
00380   /// Node const_iterators, used to iterate through all the hashtable.
00381   template<typename _Value, bool __constant_iterators, bool __cache>
00382     struct _Node_const_iterator
00383     : public _Node_iterator_base<_Value, __cache>
00384     {
00385     private:
00386       using __base_type = _Node_iterator_base<_Value, __cache>;
00387       using __node_type = typename __base_type::__node_type;
00388 
00389     public:
00390       typedef _Value                                    value_type;
00391       typedef std::ptrdiff_t                            difference_type;
00392       typedef std::forward_iterator_tag                 iterator_category;
00393 
00394       typedef const _Value*                             pointer;
00395       typedef const _Value&                             reference;
00396 
00397       _Node_const_iterator() noexcept
00398       : __base_type(0) { }
00399 
00400       explicit
00401       _Node_const_iterator(__node_type* __p) noexcept
00402       : __base_type(__p) { }
00403 
00404       _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
00405                            __cache>& __x) noexcept
00406       : __base_type(__x._M_cur) { }
00407 
00408       reference
00409       operator*() const noexcept
00410       { return this->_M_cur->_M_v(); }
00411 
00412       pointer
00413       operator->() const noexcept
00414       { return this->_M_cur->_M_valptr(); }
00415 
00416       _Node_const_iterator&
00417       operator++() noexcept
00418       {
00419         this->_M_incr();
00420         return *this;
00421       }
00422 
00423       _Node_const_iterator
00424       operator++(int) noexcept
00425       {
00426         _Node_const_iterator __tmp(*this);
00427         this->_M_incr();
00428         return __tmp;
00429       }
00430     };
00431 
00432   // Many of class template _Hashtable's template parameters are policy
00433   // classes.  These are defaults for the policies.
00434 
00435   /// Default range hashing function: use division to fold a large number
00436   /// into the range [0, N).
00437   struct _Mod_range_hashing
00438   {
00439     typedef std::size_t first_argument_type;
00440     typedef std::size_t second_argument_type;
00441     typedef std::size_t result_type;
00442 
00443     result_type
00444     operator()(first_argument_type __num,
00445                second_argument_type __den) const noexcept
00446     { return __num % __den; }
00447   };
00448 
00449   /// Default ranged hash function H.  In principle it should be a
00450   /// function object composed from objects of type H1 and H2 such that
00451   /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
00452   /// h1 and h2.  So instead we'll just use a tag to tell class template
00453   /// hashtable to do that composition.
00454   struct _Default_ranged_hash { };
00455 
00456   /// Default value for rehash policy.  Bucket size is (usually) the
00457   /// smallest prime that keeps the load factor small enough.
00458   struct _Prime_rehash_policy
00459   {
00460     _Prime_rehash_policy(float __z = 1.0) noexcept
00461     : _M_max_load_factor(__z), _M_next_resize(0) { }
00462 
00463     float
00464     max_load_factor() const noexcept
00465     { return _M_max_load_factor; }
00466 
00467     // Return a bucket size no smaller than n.
00468     std::size_t
00469     _M_next_bkt(std::size_t __n) const;
00470 
00471     // Return a bucket count appropriate for n elements
00472     std::size_t
00473     _M_bkt_for_elements(std::size_t __n) const
00474     { return __builtin_ceil(__n / (long double)_M_max_load_factor); }
00475 
00476     // __n_bkt is current bucket count, __n_elt is current element count,
00477     // and __n_ins is number of elements to be inserted.  Do we need to
00478     // increase bucket count?  If so, return make_pair(true, n), where n
00479     // is the new bucket count.  If not, return make_pair(false, 0).
00480     std::pair<bool, std::size_t>
00481     _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
00482                    std::size_t __n_ins) const;
00483 
00484     typedef std::size_t _State;
00485 
00486     _State
00487     _M_state() const
00488     { return _M_next_resize; }
00489 
00490     void
00491     _M_reset() noexcept
00492     { _M_next_resize = 0; }
00493 
00494     void
00495     _M_reset(_State __state)
00496     { _M_next_resize = __state; }
00497 
00498     static const std::size_t _S_growth_factor = 2;
00499 
00500     float               _M_max_load_factor;
00501     mutable std::size_t _M_next_resize;
00502   };
00503 
00504   // Base classes for std::_Hashtable.  We define these base classes
00505   // because in some cases we want to do different things depending on
00506   // the value of a policy class.  In some cases the policy class
00507   // affects which member functions and nested typedefs are defined;
00508   // we handle that by specializing base class templates.  Several of
00509   // the base class templates need to access other members of class
00510   // template _Hashtable, so we use a variant of the "Curiously
00511   // Recurring Template Pattern" (CRTP) technique.
00512 
00513   /**
00514    *  Primary class template _Map_base.
00515    *
00516    *  If the hashtable has a value type of the form pair<T1, T2> and a
00517    *  key extraction policy (_ExtractKey) that returns the first part
00518    *  of the pair, the hashtable gets a mapped_type typedef.  If it
00519    *  satisfies those criteria and also has unique keys, then it also
00520    *  gets an operator[].
00521    */
00522   template<typename _Key, typename _Value, typename _Alloc,
00523            typename _ExtractKey, typename _Equal,
00524            typename _H1, typename _H2, typename _Hash,
00525            typename _RehashPolicy, typename _Traits,
00526            bool _Unique_keys = _Traits::__unique_keys::value>
00527     struct _Map_base { };
00528 
00529   /// Partial specialization, __unique_keys set to false.
00530   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00531            typename _H1, typename _H2, typename _Hash,
00532            typename _RehashPolicy, typename _Traits>
00533     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00534                      _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
00535     {
00536       using mapped_type = typename std::tuple_element<1, _Pair>::type;
00537     };
00538 
00539   /// Partial specialization, __unique_keys set to true.
00540   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00541            typename _H1, typename _H2, typename _Hash,
00542            typename _RehashPolicy, typename _Traits>
00543     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00544                      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
00545     {
00546     private:
00547       using __hashtable_base = __detail::_Hashtable_base<_Key, _Pair,
00548                                                          _Select1st,
00549                                                         _Equal, _H1, _H2, _Hash,
00550                                                           _Traits>;
00551 
00552       using __hashtable = _Hashtable<_Key, _Pair, _Alloc,
00553                                      _Select1st, _Equal,
00554                                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
00555 
00556       using __hash_code = typename __hashtable_base::__hash_code;
00557       using __node_type = typename __hashtable_base::__node_type;
00558 
00559     public:
00560       using key_type = typename __hashtable_base::key_type;
00561       using iterator = typename __hashtable_base::iterator;
00562       using mapped_type = typename std::tuple_element<1, _Pair>::type;
00563 
00564       mapped_type&
00565       operator[](const key_type& __k);
00566 
00567       mapped_type&
00568       operator[](key_type&& __k);
00569 
00570       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00571       // DR 761. unordered_map needs an at() member function.
00572       mapped_type&
00573       at(const key_type& __k);
00574 
00575       const mapped_type&
00576       at(const key_type& __k) const;
00577     };
00578 
00579   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00580            typename _H1, typename _H2, typename _Hash,
00581            typename _RehashPolicy, typename _Traits>
00582     auto
00583     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00584               _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00585     operator[](const key_type& __k)
00586     -> mapped_type&
00587     {
00588       __hashtable* __h = static_cast<__hashtable*>(this);
00589       __hash_code __code = __h->_M_hash_code(__k);
00590       std::size_t __n = __h->_M_bucket_index(__k, __code);
00591       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00592 
00593       if (!__p)
00594         {
00595           __p = __h->_M_allocate_node(std::piecewise_construct,
00596                                       std::tuple<const key_type&>(__k),
00597                                       std::tuple<>());
00598           return __h->_M_insert_unique_node(__n, __code, __p)->second;
00599         }
00600 
00601       return __p->_M_v().second;
00602     }
00603 
00604   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00605            typename _H1, typename _H2, typename _Hash,
00606            typename _RehashPolicy, typename _Traits>
00607     auto
00608     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00609               _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00610     operator[](key_type&& __k)
00611     -> mapped_type&
00612     {
00613       __hashtable* __h = static_cast<__hashtable*>(this);
00614       __hash_code __code = __h->_M_hash_code(__k);
00615       std::size_t __n = __h->_M_bucket_index(__k, __code);
00616       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00617 
00618       if (!__p)
00619         {
00620           __p = __h->_M_allocate_node(std::piecewise_construct,
00621                                       std::forward_as_tuple(std::move(__k)),
00622                                       std::tuple<>());
00623           return __h->_M_insert_unique_node(__n, __code, __p)->second;
00624         }
00625 
00626       return __p->_M_v().second;
00627     }
00628 
00629   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00630            typename _H1, typename _H2, typename _Hash,
00631            typename _RehashPolicy, typename _Traits>
00632     auto
00633     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00634               _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00635     at(const key_type& __k)
00636     -> mapped_type&
00637     {
00638       __hashtable* __h = static_cast<__hashtable*>(this);
00639       __hash_code __code = __h->_M_hash_code(__k);
00640       std::size_t __n = __h->_M_bucket_index(__k, __code);
00641       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00642 
00643       if (!__p)
00644         __throw_out_of_range(__N("_Map_base::at"));
00645       return __p->_M_v().second;
00646     }
00647 
00648   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
00649            typename _H1, typename _H2, typename _Hash,
00650            typename _RehashPolicy, typename _Traits>
00651     auto
00652     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
00653               _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
00654     at(const key_type& __k) const
00655     -> const mapped_type&
00656     {
00657       const __hashtable* __h = static_cast<const __hashtable*>(this);
00658       __hash_code __code = __h->_M_hash_code(__k);
00659       std::size_t __n = __h->_M_bucket_index(__k, __code);
00660       __node_type* __p = __h->_M_find_node(__n, __k, __code);
00661 
00662       if (!__p)
00663         __throw_out_of_range(__N("_Map_base::at"));
00664       return __p->_M_v().second;
00665     }
00666 
00667   /**
00668    *  Primary class template _Insert_base.
00669    *
00670    *  insert member functions appropriate to all _Hashtables.
00671    */
00672   template<typename _Key, typename _Value, typename _Alloc,
00673            typename _ExtractKey, typename _Equal,
00674            typename _H1, typename _H2, typename _Hash,
00675            typename _RehashPolicy, typename _Traits>
00676     struct _Insert_base
00677     {
00678     protected:
00679       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
00680                                      _Equal, _H1, _H2, _Hash,
00681                                      _RehashPolicy, _Traits>;
00682 
00683       using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
00684                                                _Equal, _H1, _H2, _Hash,
00685                                                _Traits>;
00686 
00687       using value_type = typename __hashtable_base::value_type;
00688       using iterator = typename __hashtable_base::iterator;
00689       using const_iterator =  typename __hashtable_base::const_iterator;
00690       using size_type = typename __hashtable_base::size_type;
00691 
00692       using __unique_keys = typename __hashtable_base::__unique_keys;
00693       using __ireturn_type = typename __hashtable_base::__ireturn_type;
00694       using __node_type = _Hash_node<_Value, _Traits::__hash_cached::value>;
00695       using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
00696       using __node_gen_type = _AllocNode<__node_alloc_type>;
00697 
00698       __hashtable&
00699       _M_conjure_hashtable()
00700       { return *(static_cast<__hashtable*>(this)); }
00701 
00702       template<typename _InputIterator, typename _NodeGetter>
00703         void
00704         _M_insert_range(_InputIterator __first, _InputIterator __last,
00705                         const _NodeGetter&);
00706 
00707     public:
00708       __ireturn_type
00709       insert(const value_type& __v)
00710       {
00711         __hashtable& __h = _M_conjure_hashtable();
00712         __node_gen_type __node_gen(__h);
00713         return __h._M_insert(__v, __node_gen, __unique_keys());
00714       }
00715 
00716       iterator
00717       insert(const_iterator __hint, const value_type& __v)
00718       {
00719         __hashtable& __h = _M_conjure_hashtable();
00720         __node_gen_type __node_gen(__h);        
00721         return __h._M_insert(__hint, __v, __node_gen, __unique_keys());
00722       }
00723 
00724       void
00725       insert(initializer_list<value_type> __l)
00726       { this->insert(__l.begin(), __l.end()); }
00727 
00728       template<typename _InputIterator>
00729         void
00730         insert(_InputIterator __first, _InputIterator __last)
00731         {
00732           __hashtable& __h = _M_conjure_hashtable();
00733           __node_gen_type __node_gen(__h);
00734           return _M_insert_range(__first, __last, __node_gen);
00735         }
00736     };
00737 
00738   template<typename _Key, typename _Value, typename _Alloc,
00739            typename _ExtractKey, typename _Equal,
00740            typename _H1, typename _H2, typename _Hash,
00741            typename _RehashPolicy, typename _Traits>
00742     template<typename _InputIterator, typename _NodeGetter>
00743       void
00744       _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00745                     _RehashPolicy, _Traits>::
00746       _M_insert_range(_InputIterator __first, _InputIterator __last,
00747                       const _NodeGetter& __node_gen)
00748       {
00749         using __rehash_type = typename __hashtable::__rehash_type;
00750         using __rehash_state = typename __hashtable::__rehash_state;
00751         using pair_type = std::pair<bool, std::size_t>;
00752 
00753         size_type __n_elt = __detail::__distance_fw(__first, __last);
00754 
00755         __hashtable& __h = _M_conjure_hashtable();
00756         __rehash_type& __rehash = __h._M_rehash_policy;
00757         const __rehash_state& __saved_state = __rehash._M_state();
00758         pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
00759                                                         __h._M_element_count,
00760                                                         __n_elt);
00761 
00762         if (__do_rehash.first)
00763           __h._M_rehash(__do_rehash.second, __saved_state);
00764 
00765         for (; __first != __last; ++__first)
00766           __h._M_insert(*__first, __node_gen, __unique_keys());
00767       }
00768 
00769   /**
00770    *  Primary class template _Insert.
00771    *
00772    *  Select insert member functions appropriate to _Hashtable policy choices.
00773    */
00774   template<typename _Key, typename _Value, typename _Alloc,
00775            typename _ExtractKey, typename _Equal,
00776            typename _H1, typename _H2, typename _Hash,
00777            typename _RehashPolicy, typename _Traits,
00778            bool _Constant_iterators = _Traits::__constant_iterators::value,
00779            bool _Unique_keys = _Traits::__unique_keys::value>
00780     struct _Insert;
00781 
00782   /// Specialization.
00783   template<typename _Key, typename _Value, typename _Alloc,
00784            typename _ExtractKey, typename _Equal,
00785            typename _H1, typename _H2, typename _Hash,
00786            typename _RehashPolicy, typename _Traits>
00787     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00788                    _RehashPolicy, _Traits, true, true>
00789     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00790                            _H1, _H2, _Hash, _RehashPolicy, _Traits>
00791     {
00792       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00793                                         _Equal, _H1, _H2, _Hash,
00794                                         _RehashPolicy, _Traits>;
00795       using value_type = typename __base_type::value_type;
00796       using iterator = typename __base_type::iterator;
00797       using const_iterator =  typename __base_type::const_iterator;
00798 
00799       using __unique_keys = typename __base_type::__unique_keys;
00800       using __hashtable = typename __base_type::__hashtable;
00801       using __node_gen_type = typename __base_type::__node_gen_type;
00802 
00803       using __base_type::insert;
00804 
00805       std::pair<iterator, bool>
00806       insert(value_type&& __v)
00807       {
00808         __hashtable& __h = this->_M_conjure_hashtable();
00809         __node_gen_type __node_gen(__h);
00810         return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
00811       }
00812 
00813       iterator
00814       insert(const_iterator __hint, value_type&& __v)
00815       {
00816         __hashtable& __h = this->_M_conjure_hashtable();
00817         __node_gen_type __node_gen(__h);
00818         return __h._M_insert(__hint, std::move(__v), __node_gen,
00819                              __unique_keys());
00820       }
00821     };
00822 
00823   /// Specialization.
00824   template<typename _Key, typename _Value, typename _Alloc,
00825            typename _ExtractKey, typename _Equal,
00826            typename _H1, typename _H2, typename _Hash,
00827            typename _RehashPolicy, typename _Traits>
00828     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00829                    _RehashPolicy, _Traits, true, false>
00830     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00831                            _H1, _H2, _Hash, _RehashPolicy, _Traits>
00832     {
00833       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00834                                         _Equal, _H1, _H2, _Hash,
00835                                         _RehashPolicy, _Traits>;
00836       using value_type = typename __base_type::value_type;
00837       using iterator = typename __base_type::iterator;
00838       using const_iterator =  typename __base_type::const_iterator;
00839 
00840       using __unique_keys = typename __base_type::__unique_keys;
00841       using __hashtable = typename __base_type::__hashtable;
00842       using __node_gen_type = typename __base_type::__node_gen_type;
00843 
00844       using __base_type::insert;
00845 
00846       iterator
00847       insert(value_type&& __v)
00848       {
00849         __hashtable& __h = this->_M_conjure_hashtable();
00850         __node_gen_type __node_gen(__h);
00851         return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
00852       }
00853 
00854       iterator
00855       insert(const_iterator __hint, value_type&& __v)
00856       {
00857         __hashtable& __h = this->_M_conjure_hashtable();
00858         __node_gen_type __node_gen(__h);
00859         return __h._M_insert(__hint, std::move(__v), __node_gen,
00860                              __unique_keys());
00861       }
00862     };
00863 
00864   /// Specialization.
00865   template<typename _Key, typename _Value, typename _Alloc,
00866            typename _ExtractKey, typename _Equal,
00867            typename _H1, typename _H2, typename _Hash,
00868            typename _RehashPolicy, typename _Traits, bool _Unique_keys>
00869     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
00870                    _RehashPolicy, _Traits, false, _Unique_keys>
00871     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00872                            _H1, _H2, _Hash, _RehashPolicy, _Traits>
00873     {
00874       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
00875                                        _Equal, _H1, _H2, _Hash,
00876                                        _RehashPolicy, _Traits>;
00877       using value_type = typename __base_type::value_type;
00878       using iterator = typename __base_type::iterator;
00879       using const_iterator =  typename __base_type::const_iterator;
00880 
00881       using __unique_keys = typename __base_type::__unique_keys;
00882       using __hashtable = typename __base_type::__hashtable;
00883       using __ireturn_type = typename __base_type::__ireturn_type;
00884 
00885       using __base_type::insert;
00886 
00887       template<typename _Pair>
00888         using __is_cons = std::is_constructible<value_type, _Pair&&>;
00889 
00890       template<typename _Pair>
00891         using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
00892 
00893       template<typename _Pair>
00894         using _IFconsp = typename _IFcons<_Pair>::type;
00895 
00896       template<typename _Pair, typename = _IFconsp<_Pair>>
00897         __ireturn_type
00898         insert(_Pair&& __v)
00899         {
00900           __hashtable& __h = this->_M_conjure_hashtable();
00901           return __h._M_emplace(__unique_keys(), std::forward<_Pair>(__v));
00902         }
00903 
00904       template<typename _Pair, typename = _IFconsp<_Pair>>
00905         iterator
00906         insert(const_iterator __hint, _Pair&& __v)
00907         {
00908           __hashtable& __h = this->_M_conjure_hashtable();
00909           return __h._M_emplace(__hint, __unique_keys(),
00910                                 std::forward<_Pair>(__v));
00911         }
00912    };
00913 
00914   /**
00915    *  Primary class template  _Rehash_base.
00916    *
00917    *  Give hashtable the max_load_factor functions and reserve iff the
00918    *  rehash policy is _Prime_rehash_policy.
00919   */
00920   template<typename _Key, typename _Value, typename _Alloc,
00921            typename _ExtractKey, typename _Equal,
00922            typename _H1, typename _H2, typename _Hash,
00923            typename _RehashPolicy, typename _Traits>
00924     struct _Rehash_base;
00925 
00926   /// Specialization.
00927   template<typename _Key, typename _Value, typename _Alloc,
00928            typename _ExtractKey, typename _Equal,
00929            typename _H1, typename _H2, typename _Hash, typename _Traits>
00930     struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
00931                         _H1, _H2, _Hash, _Prime_rehash_policy, _Traits>
00932     {
00933       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
00934                                      _Equal, _H1, _H2, _Hash,
00935                                      _Prime_rehash_policy, _Traits>;
00936 
00937       float
00938       max_load_factor() const noexcept
00939       {
00940         const __hashtable* __this = static_cast<const __hashtable*>(this);
00941         return __this->__rehash_policy().max_load_factor();
00942       }
00943 
00944       void
00945       max_load_factor(float __z)
00946       {
00947         __hashtable* __this = static_cast<__hashtable*>(this);
00948         __this->__rehash_policy(_Prime_rehash_policy(__z));
00949       }
00950 
00951       void
00952       reserve(std::size_t __n)
00953       {
00954         __hashtable* __this = static_cast<__hashtable*>(this);
00955         __this->rehash(__builtin_ceil(__n / max_load_factor()));
00956       }
00957     };
00958 
00959   /**
00960    *  Primary class template _Hashtable_ebo_helper.
00961    *
00962    *  Helper class using EBO when it is not forbidden (the type is not
00963    *  final) and when it is worth it (the type is empty.)
00964    */
00965   template<int _Nm, typename _Tp,
00966            bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
00967     struct _Hashtable_ebo_helper;
00968 
00969   /// Specialization using EBO.
00970   template<int _Nm, typename _Tp>
00971     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
00972     : private _Tp
00973     {
00974       _Hashtable_ebo_helper() = default;
00975 
00976       template<typename _OtherTp>
00977         _Hashtable_ebo_helper(_OtherTp&& __tp)
00978           : _Tp(std::forward<_OtherTp>(__tp))
00979         { }
00980 
00981       static const _Tp&
00982       _S_cget(const _Hashtable_ebo_helper& __eboh)
00983       { return static_cast<const _Tp&>(__eboh); }
00984 
00985       static _Tp&
00986       _S_get(_Hashtable_ebo_helper& __eboh)
00987       { return static_cast<_Tp&>(__eboh); }
00988     };
00989 
00990   /// Specialization not using EBO.
00991   template<int _Nm, typename _Tp>
00992     struct _Hashtable_ebo_helper<_Nm, _Tp, false>
00993     {
00994       _Hashtable_ebo_helper() = default;
00995 
00996       template<typename _OtherTp>
00997         _Hashtable_ebo_helper(_OtherTp&& __tp)
00998           : _M_tp(std::forward<_OtherTp>(__tp))
00999         { }
01000 
01001       static const _Tp&
01002       _S_cget(const _Hashtable_ebo_helper& __eboh)
01003       { return __eboh._M_tp; }
01004 
01005       static _Tp&
01006       _S_get(_Hashtable_ebo_helper& __eboh)
01007       { return __eboh._M_tp; }
01008 
01009     private:
01010       _Tp _M_tp;
01011     };
01012 
01013   /**
01014    *  Primary class template _Local_iterator_base.
01015    *
01016    *  Base class for local iterators, used to iterate within a bucket
01017    *  but not between buckets.
01018    */
01019   template<typename _Key, typename _Value, typename _ExtractKey,
01020            typename _H1, typename _H2, typename _Hash,
01021            bool __cache_hash_code>
01022     struct _Local_iterator_base;
01023 
01024   /**
01025    *  Primary class template _Hash_code_base.
01026    *
01027    *  Encapsulates two policy issues that aren't quite orthogonal.
01028    *   (1) the difference between using a ranged hash function and using
01029    *       the combination of a hash function and a range-hashing function.
01030    *       In the former case we don't have such things as hash codes, so
01031    *       we have a dummy type as placeholder.
01032    *   (2) Whether or not we cache hash codes.  Caching hash codes is
01033    *       meaningless if we have a ranged hash function.
01034    *
01035    *  We also put the key extraction objects here, for convenience.
01036    *  Each specialization derives from one or more of the template
01037    *  parameters to benefit from Ebo. This is important as this type
01038    *  is inherited in some cases by the _Local_iterator_base type used
01039    *  to implement local_iterator and const_local_iterator. As with
01040    *  any iterator type we prefer to make it as small as possible.
01041    *
01042    *  Primary template is unused except as a hook for specializations.
01043    */
01044   template<typename _Key, typename _Value, typename _ExtractKey,
01045            typename _H1, typename _H2, typename _Hash,
01046            bool __cache_hash_code>
01047     struct _Hash_code_base;
01048 
01049   /// Specialization: ranged hash function, no caching hash codes.  H1
01050   /// and H2 are provided but ignored.  We define a dummy hash code type.
01051   template<typename _Key, typename _Value, typename _ExtractKey,
01052            typename _H1, typename _H2, typename _Hash>
01053     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, false>
01054     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01055       private _Hashtable_ebo_helper<1, _Hash>
01056     {
01057     private:
01058       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01059       using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
01060 
01061     protected:
01062       typedef void*                                     __hash_code;
01063       typedef _Hash_node<_Value, false>                 __node_type;
01064 
01065       // We need the default constructor for the local iterators and _Hashtable
01066       // default constructor.
01067       _Hash_code_base() = default;
01068 
01069       _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,
01070                       const _Hash& __h)
01071       : __ebo_extract_key(__ex), __ebo_hash(__h) { }
01072 
01073       __hash_code
01074       _M_hash_code(const _Key& __key) const
01075       { return 0; }
01076 
01077       std::size_t
01078       _M_bucket_index(const _Key& __k, __hash_code, std::size_t __n) const
01079       { return _M_ranged_hash()(__k, __n); }
01080 
01081       std::size_t
01082       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01083         noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>(),
01084                                                    (std::size_t)0)) )
01085       { return _M_ranged_hash()(_M_extract()(__p->_M_v()), __n); }
01086 
01087       void
01088       _M_store_code(__node_type*, __hash_code) const
01089       { }
01090 
01091       void
01092       _M_copy_code(__node_type*, const __node_type*) const
01093       { }
01094 
01095       void
01096       _M_swap(_Hash_code_base& __x)
01097       {
01098         std::swap(_M_extract(), __x._M_extract());
01099         std::swap(_M_ranged_hash(), __x._M_ranged_hash());
01100       }
01101 
01102       const _ExtractKey&
01103       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01104 
01105       _ExtractKey&
01106       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01107 
01108       const _Hash&
01109       _M_ranged_hash() const { return __ebo_hash::_S_cget(*this); }
01110 
01111       _Hash&
01112       _M_ranged_hash() { return __ebo_hash::_S_get(*this); }
01113     };
01114 
01115   // No specialization for ranged hash function while caching hash codes.
01116   // That combination is meaningless, and trying to do it is an error.
01117 
01118   /// Specialization: ranged hash function, cache hash codes.  This
01119   /// combination is meaningless, so we provide only a declaration
01120   /// and no definition.
01121   template<typename _Key, typename _Value, typename _ExtractKey,
01122            typename _H1, typename _H2, typename _Hash>
01123     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, true>;
01124 
01125   /// Specialization: hash function and range-hashing function, no
01126   /// caching of hash codes.
01127   /// Provides typedef and accessor required by C++ 11.
01128   template<typename _Key, typename _Value, typename _ExtractKey,
01129            typename _H1, typename _H2>
01130     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
01131                            _Default_ranged_hash, false>
01132     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01133       private _Hashtable_ebo_helper<1, _H1>,
01134       private _Hashtable_ebo_helper<2, _H2>
01135     {
01136     private:
01137       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01138       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
01139       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
01140 
01141       // Gives the local iterator implementation access to _M_bucket_index().
01142       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
01143                                          _Default_ranged_hash, false>;
01144 
01145     public:
01146       typedef _H1                                       hasher;
01147 
01148       hasher
01149       hash_function() const
01150       { return _M_h1(); }
01151 
01152     protected:
01153       typedef std::size_t                               __hash_code;
01154       typedef _Hash_node<_Value, false>                 __node_type;
01155 
01156       // We need the default constructor for the local iterators and _Hashtable
01157       // default constructor.
01158       _Hash_code_base() = default;
01159 
01160       _Hash_code_base(const _ExtractKey& __ex,
01161                       const _H1& __h1, const _H2& __h2,
01162                       const _Default_ranged_hash&)
01163       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
01164 
01165       __hash_code
01166       _M_hash_code(const _Key& __k) const
01167       { return _M_h1()(__k); }
01168 
01169       std::size_t
01170       _M_bucket_index(const _Key&, __hash_code __c, std::size_t __n) const
01171       { return _M_h2()(__c, __n); }
01172 
01173       std::size_t
01174       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01175         noexcept( noexcept(declval<const _H1&>()(declval<const _Key&>()))
01176                   && noexcept(declval<const _H2&>()((__hash_code)0,
01177                                                     (std::size_t)0)) )
01178       { return _M_h2()(_M_h1()(_M_extract()(__p->_M_v())), __n); }
01179 
01180       void
01181       _M_store_code(__node_type*, __hash_code) const
01182       { }
01183 
01184       void
01185       _M_copy_code(__node_type*, const __node_type*) const
01186       { }
01187 
01188       void
01189       _M_swap(_Hash_code_base& __x)
01190       {
01191         std::swap(_M_extract(), __x._M_extract());
01192         std::swap(_M_h1(), __x._M_h1());
01193         std::swap(_M_h2(), __x._M_h2());
01194       }
01195 
01196       const _ExtractKey&
01197       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01198 
01199       _ExtractKey&
01200       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01201 
01202       const _H1&
01203       _M_h1() const { return __ebo_h1::_S_cget(*this); }
01204 
01205       _H1&
01206       _M_h1() { return __ebo_h1::_S_get(*this); }
01207 
01208       const _H2&
01209       _M_h2() const { return __ebo_h2::_S_cget(*this); }
01210 
01211       _H2&
01212       _M_h2() { return __ebo_h2::_S_get(*this); }
01213     };
01214 
01215   /// Specialization: hash function and range-hashing function,
01216   /// caching hash codes.  H is provided but ignored.  Provides
01217   /// typedef and accessor required by C++ 11.
01218   template<typename _Key, typename _Value, typename _ExtractKey,
01219            typename _H1, typename _H2>
01220     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
01221                            _Default_ranged_hash, true>
01222     : private _Hashtable_ebo_helper<0, _ExtractKey>,
01223       private _Hashtable_ebo_helper<1, _H1>,
01224       private _Hashtable_ebo_helper<2, _H2>
01225     {
01226     private:
01227       // Gives the local iterator implementation access to _M_h2().
01228       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
01229                                          _Default_ranged_hash, true>;
01230 
01231       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
01232       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
01233       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
01234 
01235     public:
01236       typedef _H1                                       hasher;
01237 
01238       hasher
01239       hash_function() const
01240       { return _M_h1(); }
01241 
01242     protected:
01243       typedef std::size_t                               __hash_code;
01244       typedef _Hash_node<_Value, true>                  __node_type;
01245 
01246       // We need the default constructor for _Hashtable default constructor.
01247       _Hash_code_base() = default;
01248       _Hash_code_base(const _ExtractKey& __ex,
01249                       const _H1& __h1, const _H2& __h2,
01250                       const _Default_ranged_hash&)
01251       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
01252 
01253       __hash_code
01254       _M_hash_code(const _Key& __k) const
01255       { return _M_h1()(__k); }
01256 
01257       std::size_t
01258       _M_bucket_index(const _Key&, __hash_code __c,
01259                       std::size_t __n) const
01260       { return _M_h2()(__c, __n); }
01261 
01262       std::size_t
01263       _M_bucket_index(const __node_type* __p, std::size_t __n) const
01264         noexcept( noexcept(declval<const _H2&>()((__hash_code)0,
01265                                                  (std::size_t)0)) )
01266       { return _M_h2()(__p->_M_hash_code, __n); }
01267 
01268       void
01269       _M_store_code(__node_type* __n, __hash_code __c) const
01270       { __n->_M_hash_code = __c; }
01271 
01272       void
01273       _M_copy_code(__node_type* __to, const __node_type* __from) const
01274       { __to->_M_hash_code = __from->_M_hash_code; }
01275 
01276       void
01277       _M_swap(_Hash_code_base& __x)
01278       {
01279         std::swap(_M_extract(), __x._M_extract());
01280         std::swap(_M_h1(), __x._M_h1());
01281         std::swap(_M_h2(), __x._M_h2());
01282       }
01283 
01284       const _ExtractKey&
01285       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
01286 
01287       _ExtractKey&
01288       _M_extract() { return __ebo_extract_key::_S_get(*this); }
01289 
01290       const _H1&
01291       _M_h1() const { return __ebo_h1::_S_cget(*this); }
01292 
01293       _H1&
01294       _M_h1() { return __ebo_h1::_S_get(*this); }
01295 
01296       const _H2&
01297       _M_h2() const { return __ebo_h2::_S_cget(*this); }
01298 
01299       _H2&
01300       _M_h2() { return __ebo_h2::_S_get(*this); }
01301     };
01302 
01303   /**
01304    *  Primary class template _Equal_helper.
01305    *
01306    */
01307   template <typename _Key, typename _Value, typename _ExtractKey,
01308             typename _Equal, typename _HashCodeType,
01309             bool __cache_hash_code>
01310   struct _Equal_helper;
01311 
01312   /// Specialization.
01313   template<typename _Key, typename _Value, typename _ExtractKey,
01314            typename _Equal, typename _HashCodeType>
01315   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, true>
01316   {
01317     static bool
01318     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
01319               const _Key& __k, _HashCodeType __c, _Hash_node<_Value, true>* __n)
01320     { return __c == __n->_M_hash_code && __eq(__k, __extract(__n->_M_v())); }
01321   };
01322 
01323   /// Specialization.
01324   template<typename _Key, typename _Value, typename _ExtractKey,
01325            typename _Equal, typename _HashCodeType>
01326   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, false>
01327   {
01328     static bool
01329     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
01330               const _Key& __k, _HashCodeType, _Hash_node<_Value, false>* __n)
01331     { return __eq(__k, __extract(__n->_M_v())); }
01332   };
01333 
01334 
01335   /// Partial specialization used when nodes contain a cached hash code.
01336   template<typename _Key, typename _Value, typename _ExtractKey,
01337            typename _H1, typename _H2, typename _Hash>
01338     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
01339                                 _H1, _H2, _Hash, true>
01340     : private _Hashtable_ebo_helper<0, _H2>
01341     {
01342     protected:
01343       using __base_type = _Hashtable_ebo_helper<0, _H2>;
01344       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01345                                                _H1, _H2, _Hash, true>;
01346 
01347       _Local_iterator_base() = default;
01348       _Local_iterator_base(const __hash_code_base& __base,
01349                            _Hash_node<_Value, true>* __p,
01350                            std::size_t __bkt, std::size_t __bkt_count)
01351       : __base_type(__base._M_h2()),
01352         _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count) { }
01353 
01354       void
01355       _M_incr()
01356       {
01357         _M_cur = _M_cur->_M_next();
01358         if (_M_cur)
01359           {
01360             std::size_t __bkt
01361               = __base_type::_S_get(*this)(_M_cur->_M_hash_code,
01362                                            _M_bucket_count);
01363             if (__bkt != _M_bucket)
01364               _M_cur = nullptr;
01365           }
01366       }
01367 
01368       _Hash_node<_Value, true>*  _M_cur;
01369       std::size_t _M_bucket;
01370       std::size_t _M_bucket_count;
01371 
01372     public:
01373       const void*
01374       _M_curr() const { return _M_cur; }  // for equality ops
01375 
01376       std::size_t
01377       _M_get_bucket() const { return _M_bucket; }  // for debug mode
01378     };
01379 
01380   // Uninitialized storage for a _Hash_code_base.
01381   // This type is DefaultConstructible and Assignable even if the
01382   // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
01383   // can be DefaultConstructible and Assignable.
01384   template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
01385     struct _Hash_code_storage
01386     {
01387       __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
01388 
01389       _Tp*
01390       _M_h() { return _M_storage._M_ptr(); }
01391 
01392       const _Tp*
01393       _M_h() const { return _M_storage._M_ptr(); }
01394     };
01395 
01396   // Empty partial specialization for empty _Hash_code_base types.
01397   template<typename _Tp>
01398     struct _Hash_code_storage<_Tp, true>
01399     {
01400       static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
01401 
01402       // As _Tp is an empty type there will be no bytes written/read through
01403       // the cast pointer, so no strict-aliasing violation.
01404       _Tp*
01405       _M_h() { return reinterpret_cast<_Tp*>(this); }
01406 
01407       const _Tp*
01408       _M_h() const { return reinterpret_cast<const _Tp*>(this); }
01409     };
01410 
01411   template<typename _Key, typename _Value, typename _ExtractKey,
01412            typename _H1, typename _H2, typename _Hash>
01413     using __hash_code_for_local_iter
01414       = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
01415                                            _H1, _H2, _Hash, false>>;
01416 
01417   // Partial specialization used when hash codes are not cached
01418   template<typename _Key, typename _Value, typename _ExtractKey,
01419            typename _H1, typename _H2, typename _Hash>
01420     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
01421                                 _H1, _H2, _Hash, false>
01422     : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _H1, _H2, _Hash>
01423     {
01424     protected:
01425       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01426                                                _H1, _H2, _Hash, false>;
01427 
01428       _Local_iterator_base() : _M_bucket_count(-1) { }
01429 
01430       _Local_iterator_base(const __hash_code_base& __base,
01431                            _Hash_node<_Value, false>* __p,
01432                            std::size_t __bkt, std::size_t __bkt_count)
01433       : _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
01434       { _M_init(__base); }
01435 
01436       ~_Local_iterator_base()
01437       {
01438         if (_M_bucket_count != -1)
01439           _M_destroy();
01440       }
01441 
01442       _Local_iterator_base(const _Local_iterator_base& __iter)
01443       : _M_cur(__iter._M_cur), _M_bucket(__iter._M_bucket),
01444         _M_bucket_count(__iter._M_bucket_count)
01445       {
01446         if (_M_bucket_count != -1)
01447           _M_init(*__iter._M_h());
01448       }
01449 
01450       _Local_iterator_base&
01451       operator=(const _Local_iterator_base& __iter)
01452       {
01453         if (_M_bucket_count != -1)
01454           _M_destroy();
01455         _M_cur = __iter._M_cur;
01456         _M_bucket = __iter._M_bucket;
01457         _M_bucket_count = __iter._M_bucket_count;
01458         if (_M_bucket_count != -1)
01459           _M_init(*__iter._M_h());
01460         return *this;
01461       }
01462 
01463       void
01464       _M_incr()
01465       {
01466         _M_cur = _M_cur->_M_next();
01467         if (_M_cur)
01468           {
01469             std::size_t __bkt = this->_M_h()->_M_bucket_index(_M_cur,
01470                                                               _M_bucket_count);
01471             if (__bkt != _M_bucket)
01472               _M_cur = nullptr;
01473           }
01474       }
01475 
01476       _Hash_node<_Value, false>*  _M_cur;
01477       std::size_t _M_bucket;
01478       std::size_t _M_bucket_count;
01479 
01480       void
01481       _M_init(const __hash_code_base& __base)
01482       { ::new(this->_M_h()) __hash_code_base(__base); }
01483 
01484       void
01485       _M_destroy() { this->_M_h()->~__hash_code_base(); }
01486 
01487     public:
01488       const void*
01489       _M_curr() const { return _M_cur; }  // for equality ops and debug mode
01490 
01491       std::size_t
01492       _M_get_bucket() const { return _M_bucket; }  // for debug mode
01493     };
01494 
01495   template<typename _Key, typename _Value, typename _ExtractKey,
01496            typename _H1, typename _H2, typename _Hash, bool __cache>
01497     inline bool
01498     operator==(const _Local_iterator_base<_Key, _Value, _ExtractKey,
01499                                           _H1, _H2, _Hash, __cache>& __x,
01500                const _Local_iterator_base<_Key, _Value, _ExtractKey,
01501                                           _H1, _H2, _Hash, __cache>& __y)
01502     { return __x._M_curr() == __y._M_curr(); }
01503 
01504   template<typename _Key, typename _Value, typename _ExtractKey,
01505            typename _H1, typename _H2, typename _Hash, bool __cache>
01506     inline bool
01507     operator!=(const _Local_iterator_base<_Key, _Value, _ExtractKey,
01508                                           _H1, _H2, _Hash, __cache>& __x,
01509                const _Local_iterator_base<_Key, _Value, _ExtractKey,
01510                                           _H1, _H2, _Hash, __cache>& __y)
01511     { return __x._M_curr() != __y._M_curr(); }
01512 
01513   /// local iterators
01514   template<typename _Key, typename _Value, typename _ExtractKey,
01515            typename _H1, typename _H2, typename _Hash,
01516            bool __constant_iterators, bool __cache>
01517     struct _Local_iterator
01518     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
01519                                   _H1, _H2, _Hash, __cache>
01520     {
01521     private:
01522       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
01523                                                _H1, _H2, _Hash, __cache>;
01524       using __hash_code_base = typename __base_type::__hash_code_base;
01525     public:
01526       typedef _Value                                    value_type;
01527       typedef typename std::conditional<__constant_iterators,
01528                                         const _Value*, _Value*>::type
01529                                                        pointer;
01530       typedef typename std::conditional<__constant_iterators,
01531                                         const _Value&, _Value&>::type
01532                                                        reference;
01533       typedef std::ptrdiff_t                            difference_type;
01534       typedef std::forward_iterator_tag                 iterator_category;
01535 
01536       _Local_iterator() = default;
01537 
01538       _Local_iterator(const __hash_code_base& __base,
01539                       _Hash_node<_Value, __cache>* __p,
01540                       std::size_t __bkt, std::size_t __bkt_count)
01541         : __base_type(__base, __p, __bkt, __bkt_count)
01542       { }
01543 
01544       reference
01545       operator*() const
01546       { return this->_M_cur->_M_v(); }
01547 
01548       pointer
01549       operator->() const
01550       { return this->_M_cur->_M_valptr(); }
01551 
01552       _Local_iterator&
01553       operator++()
01554       {
01555         this->_M_incr();
01556         return *this;
01557       }
01558 
01559       _Local_iterator
01560       operator++(int)
01561       {
01562         _Local_iterator __tmp(*this);
01563         this->_M_incr();
01564         return __tmp;
01565       }
01566     };
01567 
01568   /// local const_iterators
01569   template<typename _Key, typename _Value, typename _ExtractKey,
01570            typename _H1, typename _H2, typename _Hash,
01571            bool __constant_iterators, bool __cache>
01572     struct _Local_const_iterator
01573     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
01574                                   _H1, _H2, _Hash, __cache>
01575     {
01576     private:
01577       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
01578                                                _H1, _H2, _Hash, __cache>;
01579       using __hash_code_base = typename __base_type::__hash_code_base;
01580 
01581     public:
01582       typedef _Value                                    value_type;
01583       typedef const _Value*                             pointer;
01584       typedef const _Value&                             reference;
01585       typedef std::ptrdiff_t                            difference_type;
01586       typedef std::forward_iterator_tag                 iterator_category;
01587 
01588       _Local_const_iterator() = default;
01589 
01590       _Local_const_iterator(const __hash_code_base& __base,
01591                             _Hash_node<_Value, __cache>* __p,
01592                             std::size_t __bkt, std::size_t __bkt_count)
01593         : __base_type(__base, __p, __bkt, __bkt_count)
01594       { }
01595 
01596       _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
01597                                                   _H1, _H2, _Hash,
01598                                                   __constant_iterators,
01599                                                   __cache>& __x)
01600         : __base_type(__x)
01601       { }
01602 
01603       reference
01604       operator*() const
01605       { return this->_M_cur->_M_v(); }
01606 
01607       pointer
01608       operator->() const
01609       { return this->_M_cur->_M_valptr(); }
01610 
01611       _Local_const_iterator&
01612       operator++()
01613       {
01614         this->_M_incr();
01615         return *this;
01616       }
01617 
01618       _Local_const_iterator
01619       operator++(int)
01620       {
01621         _Local_const_iterator __tmp(*this);
01622         this->_M_incr();
01623         return __tmp;
01624       }
01625     };
01626 
01627   /**
01628    *  Primary class template _Hashtable_base.
01629    *
01630    *  Helper class adding management of _Equal functor to
01631    *  _Hash_code_base type.
01632    *
01633    *  Base class templates are:
01634    *    - __detail::_Hash_code_base
01635    *    - __detail::_Hashtable_ebo_helper
01636    */
01637   template<typename _Key, typename _Value,
01638            typename _ExtractKey, typename _Equal,
01639            typename _H1, typename _H2, typename _Hash, typename _Traits>
01640   struct _Hashtable_base
01641   : public _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash,
01642                            _Traits::__hash_cached::value>,
01643     private _Hashtable_ebo_helper<0, _Equal>
01644   {
01645   public:
01646     typedef _Key                                        key_type;
01647     typedef _Value                                      value_type;
01648     typedef _Equal                                      key_equal;
01649     typedef std::size_t                                 size_type;
01650     typedef std::ptrdiff_t                              difference_type;
01651 
01652     using __traits_type = _Traits;
01653     using __hash_cached = typename __traits_type::__hash_cached;
01654     using __constant_iterators = typename __traits_type::__constant_iterators;
01655     using __unique_keys = typename __traits_type::__unique_keys;
01656 
01657     using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
01658                                              _H1, _H2, _Hash,
01659                                              __hash_cached::value>;
01660 
01661     using __hash_code = typename __hash_code_base::__hash_code;
01662     using __node_type = typename __hash_code_base::__node_type;
01663 
01664     using iterator = __detail::_Node_iterator<value_type,
01665                                               __constant_iterators::value,
01666                                               __hash_cached::value>;
01667 
01668     using const_iterator = __detail::_Node_const_iterator<value_type,
01669                                                    __constant_iterators::value,
01670                                                    __hash_cached::value>;
01671 
01672     using local_iterator = __detail::_Local_iterator<key_type, value_type,
01673                                                   _ExtractKey, _H1, _H2, _Hash,
01674                                                   __constant_iterators::value,
01675                                                      __hash_cached::value>;
01676 
01677     using const_local_iterator = __detail::_Local_const_iterator<key_type,
01678                                                                  value_type,
01679                                         _ExtractKey, _H1, _H2, _Hash,
01680                                         __constant_iterators::value,
01681                                         __hash_cached::value>;
01682 
01683     using __ireturn_type = typename std::conditional<__unique_keys::value,
01684                                                      std::pair<iterator, bool>,
01685                                                      iterator>::type;
01686   private:
01687     using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
01688     using _EqualHelper =  _Equal_helper<_Key, _Value, _ExtractKey, _Equal,
01689                                         __hash_code, __hash_cached::value>;
01690 
01691   protected:
01692     _Hashtable_base() = default;
01693     _Hashtable_base(const _ExtractKey& __ex, const _H1& __h1, const _H2& __h2,
01694                     const _Hash& __hash, const _Equal& __eq)
01695     : __hash_code_base(__ex, __h1, __h2, __hash), _EqualEBO(__eq)
01696     { }
01697 
01698     bool
01699     _M_equals(const _Key& __k, __hash_code __c, __node_type* __n) const
01700     {
01701       return _EqualHelper::_S_equals(_M_eq(), this->_M_extract(),
01702                                      __k, __c, __n);
01703     }
01704 
01705     void
01706     _M_swap(_Hashtable_base& __x)
01707     {
01708       __hash_code_base::_M_swap(__x);
01709       std::swap(_M_eq(), __x._M_eq());
01710     }
01711 
01712     const _Equal&
01713     _M_eq() const { return _EqualEBO::_S_cget(*this); }
01714 
01715     _Equal&
01716     _M_eq() { return _EqualEBO::_S_get(*this); }
01717   };
01718 
01719   /**
01720    *  struct _Equality_base.
01721    *
01722    *  Common types and functions for class _Equality.
01723    */
01724   struct _Equality_base
01725   {
01726   protected:
01727     template<typename _Uiterator>
01728       static bool
01729       _S_is_permutation(_Uiterator, _Uiterator, _Uiterator);
01730   };
01731 
01732   // See std::is_permutation in N3068.
01733   template<typename _Uiterator>
01734     bool
01735     _Equality_base::
01736     _S_is_permutation(_Uiterator __first1, _Uiterator __last1,
01737                       _Uiterator __first2)
01738     {
01739       for (; __first1 != __last1; ++__first1, ++__first2)
01740         if (!(*__first1 == *__first2))
01741           break;
01742 
01743       if (__first1 == __last1)
01744         return true;
01745 
01746       _Uiterator __last2 = __first2;
01747       std::advance(__last2, std::distance(__first1, __last1));
01748 
01749       for (_Uiterator __it1 = __first1; __it1 != __last1; ++__it1)
01750         {
01751           _Uiterator __tmp =  __first1;
01752           while (__tmp != __it1 && !bool(*__tmp == *__it1))
01753             ++__tmp;
01754 
01755           // We've seen this one before.
01756           if (__tmp != __it1)
01757             continue;
01758 
01759           std::ptrdiff_t __n2 = 0;
01760           for (__tmp = __first2; __tmp != __last2; ++__tmp)
01761             if (*__tmp == *__it1)
01762               ++__n2;
01763 
01764           if (!__n2)
01765             return false;
01766 
01767           std::ptrdiff_t __n1 = 0;
01768           for (__tmp = __it1; __tmp != __last1; ++__tmp)
01769             if (*__tmp == *__it1)
01770               ++__n1;
01771 
01772           if (__n1 != __n2)
01773             return false;
01774         }
01775       return true;
01776     }
01777 
01778   /**
01779    *  Primary class template  _Equality.
01780    *
01781    *  This is for implementing equality comparison for unordered
01782    *  containers, per N3068, by John Lakos and Pablo Halpern.
01783    *  Algorithmically, we follow closely the reference implementations
01784    *  therein.
01785    */
01786   template<typename _Key, typename _Value, typename _Alloc,
01787            typename _ExtractKey, typename _Equal,
01788            typename _H1, typename _H2, typename _Hash,
01789            typename _RehashPolicy, typename _Traits,
01790            bool _Unique_keys = _Traits::__unique_keys::value>
01791     struct _Equality;
01792 
01793   /// Specialization.
01794   template<typename _Key, typename _Value, typename _Alloc,
01795            typename _ExtractKey, typename _Equal,
01796            typename _H1, typename _H2, typename _Hash,
01797            typename _RehashPolicy, typename _Traits>
01798     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01799                      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
01800     {
01801       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01802                                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
01803 
01804       bool
01805       _M_equal(const __hashtable&) const;
01806     };
01807 
01808   template<typename _Key, typename _Value, typename _Alloc,
01809            typename _ExtractKey, typename _Equal,
01810            typename _H1, typename _H2, typename _Hash,
01811            typename _RehashPolicy, typename _Traits>
01812     bool
01813     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01814               _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
01815     _M_equal(const __hashtable& __other) const
01816     {
01817       const __hashtable* __this = static_cast<const __hashtable*>(this);
01818 
01819       if (__this->size() != __other.size())
01820         return false;
01821 
01822       for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
01823         {
01824           const auto __ity = __other.find(_ExtractKey()(*__itx));
01825           if (__ity == __other.end() || !bool(*__ity == *__itx))
01826             return false;
01827         }
01828       return true;
01829     }
01830 
01831   /// Specialization.
01832   template<typename _Key, typename _Value, typename _Alloc,
01833            typename _ExtractKey, typename _Equal,
01834            typename _H1, typename _H2, typename _Hash,
01835            typename _RehashPolicy, typename _Traits>
01836     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01837                      _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
01838     : public _Equality_base
01839     {
01840       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01841                                      _H1, _H2, _Hash, _RehashPolicy, _Traits>;
01842 
01843       bool
01844       _M_equal(const __hashtable&) const;
01845     };
01846 
01847   template<typename _Key, typename _Value, typename _Alloc,
01848            typename _ExtractKey, typename _Equal,
01849            typename _H1, typename _H2, typename _Hash,
01850            typename _RehashPolicy, typename _Traits>
01851     bool
01852     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
01853               _H1, _H2, _Hash, _RehashPolicy, _Traits, false>::
01854     _M_equal(const __hashtable& __other) const
01855     {
01856       const __hashtable* __this = static_cast<const __hashtable*>(this);
01857 
01858       if (__this->size() != __other.size())
01859         return false;
01860 
01861       for (auto __itx = __this->begin(); __itx != __this->end();)
01862         {
01863           const auto __xrange = __this->equal_range(_ExtractKey()(*__itx));
01864           const auto __yrange = __other.equal_range(_ExtractKey()(*__itx));
01865 
01866           if (std::distance(__xrange.first, __xrange.second)
01867               != std::distance(__yrange.first, __yrange.second))
01868             return false;
01869 
01870           if (!_S_is_permutation(__xrange.first, __xrange.second,
01871                                  __yrange.first))
01872             return false;
01873 
01874           __itx = __xrange.second;
01875         }
01876       return true;
01877     }
01878 
01879   /**
01880    * This type deals with all allocation and keeps an allocator instance through
01881    * inheritance to benefit from EBO when possible.
01882    */
01883   template<typename _NodeAlloc>
01884     struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
01885     {
01886     private:
01887       using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
01888     public:
01889       using __node_type = typename _NodeAlloc::value_type;
01890       using __node_alloc_type = _NodeAlloc;
01891       // Use __gnu_cxx to benefit from _S_always_equal and al.
01892       using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
01893 
01894       using __value_type = typename __node_type::value_type;
01895       using __value_alloc_type =
01896         __alloc_rebind<__node_alloc_type, __value_type>;
01897       using __value_alloc_traits = std::allocator_traits<__value_alloc_type>;
01898 
01899       using __node_base = __detail::_Hash_node_base;
01900       using __bucket_type = __node_base*;      
01901       using __bucket_alloc_type =
01902         __alloc_rebind<__node_alloc_type, __bucket_type>;
01903       using __bucket_alloc_traits = std::allocator_traits<__bucket_alloc_type>;
01904 
01905       _Hashtable_alloc() = default;
01906       _Hashtable_alloc(const _Hashtable_alloc&) = default;
01907       _Hashtable_alloc(_Hashtable_alloc&&) = default;
01908 
01909       template<typename _Alloc>
01910         _Hashtable_alloc(_Alloc&& __a)
01911           : __ebo_node_alloc(std::forward<_Alloc>(__a))
01912         { }
01913 
01914       __node_alloc_type&
01915       _M_node_allocator()
01916       { return __ebo_node_alloc::_S_get(*this); }
01917 
01918       const __node_alloc_type&
01919       _M_node_allocator() const
01920       { return __ebo_node_alloc::_S_cget(*this); }
01921 
01922       template<typename... _Args>
01923         __node_type*
01924         _M_allocate_node(_Args&&... __args);
01925 
01926       void
01927       _M_deallocate_node(__node_type* __n);
01928 
01929       // Deallocate the linked list of nodes pointed to by __n
01930       void
01931       _M_deallocate_nodes(__node_type* __n);
01932 
01933       __bucket_type*
01934       _M_allocate_buckets(std::size_t __n);
01935 
01936       void
01937       _M_deallocate_buckets(__bucket_type*, std::size_t __n);
01938     };
01939 
01940   // Definitions of class template _Hashtable_alloc's out-of-line member
01941   // functions.
01942   template<typename _NodeAlloc>
01943     template<typename... _Args>
01944       typename _Hashtable_alloc<_NodeAlloc>::__node_type*
01945       _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
01946       {
01947         auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
01948         __node_type* __n = std::__addressof(*__nptr);
01949         __try
01950           {
01951             __value_alloc_type __a(_M_node_allocator());
01952             ::new ((void*)__n) __node_type;
01953             __value_alloc_traits::construct(__a, __n->_M_valptr(),
01954                                             std::forward<_Args>(__args)...);
01955             return __n;
01956           }
01957         __catch(...)
01958           {
01959             __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
01960             __throw_exception_again;
01961           }
01962       }
01963 
01964   template<typename _NodeAlloc>
01965     void
01966     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_type* __n)
01967     {
01968       typedef typename __node_alloc_traits::pointer _Ptr;
01969       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
01970       __value_alloc_type __a(_M_node_allocator());
01971       __value_alloc_traits::destroy(__a, __n->_M_valptr());
01972       __n->~__node_type();
01973       __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
01974     }
01975 
01976   template<typename _NodeAlloc>
01977     void
01978     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_type* __n)
01979     {
01980       while (__n)
01981         {
01982           __node_type* __tmp = __n;
01983           __n = __n->_M_next();
01984           _M_deallocate_node(__tmp);
01985         }
01986     }
01987 
01988   template<typename _NodeAlloc>
01989     typename _Hashtable_alloc<_NodeAlloc>::__bucket_type*
01990     _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __n)
01991     {
01992       __bucket_alloc_type __alloc(_M_node_allocator());
01993 
01994       auto __ptr = __bucket_alloc_traits::allocate(__alloc, __n);
01995       __bucket_type* __p = std::__addressof(*__ptr);
01996       __builtin_memset(__p, 0, __n * sizeof(__bucket_type));
01997       return __p;
01998     }
01999 
02000   template<typename _NodeAlloc>
02001     void
02002     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_buckets(__bucket_type* __bkts,
02003                                                         std::size_t __n)
02004     {
02005       typedef typename __bucket_alloc_traits::pointer _Ptr;
02006       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
02007       __bucket_alloc_type __alloc(_M_node_allocator());
02008       __bucket_alloc_traits::deallocate(__alloc, __ptr, __n);
02009     }
02010 
02011  //@} hashtable-detail
02012 _GLIBCXX_END_NAMESPACE_VERSION
02013 } // namespace __detail
02014 } // namespace std
02015 
02016 #endif // _HASHTABLE_POLICY_H