Subversion Repositories Kolibri OS

// Internal policy header for unordered_set and unordered_map -*- C++ -*-

// Copyright (C) 2010-2013 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 3, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

// .

/** @file bits/hashtable_policy.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly.

 *  @headername{unordered_map,unordered_set}

 */

#ifndef _HASHTABLE_POLICY_H

#define _HASHTABLE_POLICY_H 1

namespace std _GLIBCXX_VISIBILITY(default)

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    class _Hashtable;

_GLIBCXX_END_NAMESPACE_VERSION

namespace __detail

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**

   *  @defgroup hashtable-detail Base and Implementation Classes

   *  @ingroup unordered_associative_containers

   *  @{

   */

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash, typename _Traits>

    struct _Hashtable_base;

  // Helper function: return distance(first, last) for forward

  // iterators, or 0 for input iterators.

  template

    inline typename std::iterator_traits<_Iterator>::difference_type

    __distance_fw(_Iterator __first, _Iterator __last,

		  std::input_iterator_tag)

    { return 0; }

  template

    inline typename std::iterator_traits<_Iterator>::difference_type

    __distance_fw(_Iterator __first, _Iterator __last,

		  std::forward_iterator_tag)

    { return std::distance(__first, __last); }

  template

    inline typename std::iterator_traits<_Iterator>::difference_type

    __distance_fw(_Iterator __first, _Iterator __last)

    {

      typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag;

      return __distance_fw(__first, __last, _Tag());

    }

  // Helper type used to detect whether the hash functor is noexcept.

  template 

    struct __is_noexcept_hash : std::integral_constant

	noexcept(declval()(declval()))>

    { };

  struct _Identity

  {

    template

      _Tp&&

      operator()(_Tp&& __x) const

      { return std::forward<_Tp>(__x); }

  };

  struct _Select1st

  {

    template

      auto

      operator()(_Tp&& __x) const

      -> decltype(std::get<0>(std::forward<_Tp>(__x)))

      { return std::get<0>(std::forward<_Tp>(__x)); }

  };

  // Auxiliary types used for all instantiations of _Hashtable nodes

  // and iterators.

  /**

   *  struct _Hashtable_traits

   *

   *  Important traits for hash tables.

   *

   *  @tparam _Cache_hash_code  Boolean value. True if the value of

   *  the hash function is stored along with the value. This is a

   *  time-space tradeoff.  Storing it may improve lookup speed by

   *  reducing the number of times we need to call the _Equal

   *  function.

   *

   *  @tparam _Constant_iterators  Boolean value. True if iterator and

   *  const_iterator are both constant iterator types. This is true

   *  for unordered_set and unordered_multiset, false for

   *  unordered_map and unordered_multimap.

   *

   *  @tparam _Unique_keys  Boolean value. True if the return value

   *  of _Hashtable::count(k) is always at most one, false if it may

   *  be an arbitrary number. This is true for unordered_set and

   *  unordered_map, false for unordered_multiset and

   *  unordered_multimap.

   */

  template

    struct _Hashtable_traits

    {

      template

	using __bool_constant = integral_constant;

      using __hash_cached = __bool_constant<_Cache_hash_code>;

      using __constant_iterators = __bool_constant<_Constant_iterators>;

      using __unique_keys = __bool_constant<_Unique_keys>;

    };

  /**

   *  struct _Hash_node_base

   *

   *  Nodes, used to wrap elements stored in the hash table.  A policy

   *  template parameter of class template _Hashtable controls whether

   *  nodes also store a hash code. In some cases (e.g. strings) this

   *  may be a performance win.

   */

  struct _Hash_node_base

  {

    _Hash_node_base* _M_nxt;

    _Hash_node_base() : _M_nxt() { }

    _Hash_node_base(_Hash_node_base* __next) : _M_nxt(__next) { }

  };

  /**

   *  Primary template struct _Hash_node.

   */

  template

    struct _Hash_node;

  /**

   *  Specialization for nodes with caches, struct _Hash_node.

   *

   *  Base class is __detail::_Hash_node_base.

   */

  template

    struct _Hash_node<_Value, true> : _Hash_node_base

    {

      _Value       _M_v;

      std::size_t  _M_hash_code;

      template

	_Hash_node(_Args&&... __args)

	: _M_v(std::forward<_Args>(__args)...), _M_hash_code() { }

      _Hash_node*

      _M_next() const { return static_cast<_Hash_node*>(_M_nxt); }

    };

  /**

   *  Specialization for nodes without caches, struct _Hash_node.

   *

   *  Base class is __detail::_Hash_node_base.

   */

  template

    struct _Hash_node<_Value, false> : _Hash_node_base

    {

      _Value       _M_v;

      template

	_Hash_node(_Args&&... __args)

	: _M_v(std::forward<_Args>(__args)...) { }

      _Hash_node*

      _M_next() const { return static_cast<_Hash_node*>(_M_nxt); }

    };

  /// Base class for node iterators.

  template

    struct _Node_iterator_base

    {

      using __node_type = _Hash_node<_Value, _Cache_hash_code>;

      __node_type*  _M_cur;

      _Node_iterator_base(__node_type* __p)

      : _M_cur(__p) { }

      void

      _M_incr()

      { _M_cur = _M_cur->_M_next(); }

    };

  template

    inline bool

    operator==(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,

	       const _Node_iterator_base<_Value, _Cache_hash_code >& __y)

    { return __x._M_cur == __y._M_cur; }

  template

    inline bool

    operator!=(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,

	       const _Node_iterator_base<_Value, _Cache_hash_code>& __y)

    { return __x._M_cur != __y._M_cur; }

  /// Node iterators, used to iterate through all the hashtable.

  template

    struct _Node_iterator

    : public _Node_iterator_base<_Value, __cache>

    {

    private:

      using __base_type = _Node_iterator_base<_Value, __cache>;

      using __node_type = typename __base_type::__node_type;

    public:

      typedef _Value                                   value_type;

      typedef std::ptrdiff_t                           difference_type;

      typedef std::forward_iterator_tag                iterator_category;

      using pointer = typename std::conditional<__constant_iterators,

						const _Value*, _Value*>::type;

      using reference = typename std::conditional<__constant_iterators,

						  const _Value&, _Value&>::type;

      _Node_iterator()

      : __base_type(0) { }

      explicit

      _Node_iterator(__node_type* __p)

      : __base_type(__p) { }

      reference

      operator*() const

      { return this->_M_cur->_M_v; }

      pointer

      operator->() const

      { return std::__addressof(this->_M_cur->_M_v); }

      _Node_iterator&

      operator++()

      {

	this->_M_incr();

	return *this;

      }

      _Node_iterator

      operator++(int)

      {

	_Node_iterator __tmp(*this);

	this->_M_incr();

	return __tmp;

      }

    };

  /// Node const_iterators, used to iterate through all the hashtable.

  template

    struct _Node_const_iterator

    : public _Node_iterator_base<_Value, __cache>

    {

    private:

      using __base_type = _Node_iterator_base<_Value, __cache>;

      using __node_type = typename __base_type::__node_type;

    public:

      typedef _Value                                   value_type;

      typedef std::ptrdiff_t                           difference_type;

      typedef std::forward_iterator_tag                iterator_category;

      typedef const _Value*                            pointer;

      typedef const _Value&                            reference;

      _Node_const_iterator()

      : __base_type(0) { }

      explicit

      _Node_const_iterator(__node_type* __p)

      : __base_type(__p) { }

      _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,

			   __cache>& __x)

      : __base_type(__x._M_cur) { }

      reference

      operator*() const

      { return this->_M_cur->_M_v; }

      pointer

      operator->() const

      { return std::__addressof(this->_M_cur->_M_v); }

      _Node_const_iterator&

      operator++()

      {

	this->_M_incr();

	return *this;

      }

      _Node_const_iterator

      operator++(int)

      {

	_Node_const_iterator __tmp(*this);

	this->_M_incr();

	return __tmp;

      }

    };

  // Many of class template _Hashtable's template parameters are policy

  // classes.  These are defaults for the policies.

  /// Default range hashing function: use division to fold a large number

  /// into the range [0, N).

  struct _Mod_range_hashing

  {

    typedef std::size_t first_argument_type;

    typedef std::size_t second_argument_type;

    typedef std::size_t result_type;

    result_type

    operator()(first_argument_type __num, second_argument_type __den) const

    { return __num % __den; }

  };

  /// Default ranged hash function H.  In principle it should be a

  /// function object composed from objects of type H1 and H2 such that

  /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of

  /// h1 and h2.  So instead we'll just use a tag to tell class template

  /// hashtable to do that composition.

  struct _Default_ranged_hash { };

  /// Default value for rehash policy.  Bucket size is (usually) the

  /// smallest prime that keeps the load factor small enough.

  struct _Prime_rehash_policy

  {

    _Prime_rehash_policy(float __z = 1.0)

    : _M_max_load_factor(__z), _M_next_resize(0) { }

    float

    max_load_factor() const noexcept

    { return _M_max_load_factor; }

    // Return a bucket size no smaller than n.

    std::size_t

    _M_next_bkt(std::size_t __n) const;

    // Return a bucket count appropriate for n elements

    std::size_t

    _M_bkt_for_elements(std::size_t __n) const

    { return __builtin_ceil(__n / (long double)_M_max_load_factor); }

    // __n_bkt is current bucket count, __n_elt is current element count,

    // and __n_ins is number of elements to be inserted.  Do we need to

    // increase bucket count?  If so, return make_pair(true, n), where n

    // is the new bucket count.  If not, return make_pair(false, 0).

    std::pair

    _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,

		   std::size_t __n_ins) const;

    typedef std::size_t _State;

    _State

    _M_state() const

    { return _M_next_resize; }

    void

    _M_reset(_State __state)

    { _M_next_resize = __state; }

    enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 };

    static const std::size_t _S_growth_factor = 2;

    float                _M_max_load_factor;

    mutable std::size_t  _M_next_resize;

  };

  // Base classes for std::_Hashtable.  We define these base classes

  // because in some cases we want to do different things depending on

  // the value of a policy class.  In some cases the policy class

  // affects which member functions and nested typedefs are defined;

  // we handle that by specializing base class templates.  Several of

  // the base class templates need to access other members of class

  // template _Hashtable, so we use a variant of the "Curiously

  // Recurring Template Pattern" (CRTP) technique.

  /**

   *  Primary class template _Map_base.

   *

   *  If the hashtable has a value type of the form pair and a

   *  key extraction policy (_ExtractKey) that returns the first part

   *  of the pair, the hashtable gets a mapped_type typedef.  If it

   *  satisfies those criteria and also has unique keys, then it also

   *  gets an operator[].

   */

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits,

	   bool _Unique_keys = _Traits::__unique_keys::value>

    struct _Map_base { };

  /// Partial specialization, __unique_keys set to false.

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

		     _H1, _H2, _Hash, _RehashPolicy, _Traits, false>

    {

      using mapped_type = typename std::tuple_element<1, _Pair>::type;

    };

  /// Partial specialization, __unique_keys set to true.

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

		     _H1, _H2, _Hash, _RehashPolicy, _Traits, true>

    {

    private:

      using __hashtable_base = __detail::_Hashtable_base<_Key, _Pair,

							 _Select1st,

							_Equal, _H1, _H2, _Hash,

							  _Traits>;

      using __hashtable = _Hashtable<_Key, _Pair, _Alloc,

				     _Select1st, _Equal,

				     _H1, _H2, _Hash, _RehashPolicy, _Traits>;

      using __hash_code = typename __hashtable_base::__hash_code;

      using __node_type = typename __hashtable_base::__node_type;

    public:

      using key_type = typename __hashtable_base::key_type;

      using iterator = typename __hashtable_base::iterator;

      using mapped_type = typename std::tuple_element<1, _Pair>::type;

      mapped_type&

      operator[](const key_type& __k);

      mapped_type&

      operator[](key_type&& __k);

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // DR 761. unordered_map needs an at() member function.

      mapped_type&

      at(const key_type& __k);

      const mapped_type&

      at(const key_type& __k) const;

    };

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

		       _H1, _H2, _Hash, _RehashPolicy, _Traits, true>

		       ::mapped_type&

    _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::

    operator[](const key_type& __k)

    {

      __hashtable* __h = static_cast<__hashtable*>(this);

      __hash_code __code = __h->_M_hash_code(__k);

      std::size_t __n = __h->_M_bucket_index(__k, __code);

      __node_type* __p = __h->_M_find_node(__n, __k, __code);

      if (!__p)

	{

	  __p = __h->_M_allocate_node(std::piecewise_construct,

				      std::tuple(__k),

				      std::tuple<>());

	  return __h->_M_insert_unique_node(__n, __code, __p)->second;

	}

      return (__p->_M_v).second;

    }

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

		       _H1, _H2, _Hash, _RehashPolicy, _Traits, true>

		       ::mapped_type&

    _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::

    operator[](key_type&& __k)

    {

      __hashtable* __h = static_cast<__hashtable*>(this);

      __hash_code __code = __h->_M_hash_code(__k);

      std::size_t __n = __h->_M_bucket_index(__k, __code);

      __node_type* __p = __h->_M_find_node(__n, __k, __code);

      if (!__p)

	{

	  __p = __h->_M_allocate_node(std::piecewise_construct,

				      std::forward_as_tuple(std::move(__k)),

				      std::tuple<>());

	  return __h->_M_insert_unique_node(__n, __code, __p)->second;

	}

      return (__p->_M_v).second;

    }

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    typename _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

		       _H1, _H2, _Hash, _RehashPolicy, _Traits, true>

		       ::mapped_type&

    _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::

    at(const key_type& __k)

    {

      __hashtable* __h = static_cast<__hashtable*>(this);

      __hash_code __code = __h->_M_hash_code(__k);

      std::size_t __n = __h->_M_bucket_index(__k, __code);

      __node_type* __p = __h->_M_find_node(__n, __k, __code);

      if (!__p)

	__throw_out_of_range(__N("_Map_base::at"));

      return (__p->_M_v).second;

    }

  template

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    const typename _Map_base<_Key, _Pair, _Alloc, _Select1st,

			     _Equal, _H1, _H2, _Hash, _RehashPolicy,

			     _Traits, true>::mapped_type&

    _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,

	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::

    at(const key_type& __k) const

    {

      const __hashtable* __h = static_cast(this);

      __hash_code __code = __h->_M_hash_code(__k);

      std::size_t __n = __h->_M_bucket_index(__k, __code);

      __node_type* __p = __h->_M_find_node(__n, __k, __code);

      if (!__p)

	__throw_out_of_range(__N("_Map_base::at"));

      return (__p->_M_v).second;

    }

  /**

   *  Primary class template _Insert_base.

   *

   *  insert member functions appropriate to all _Hashtables.

   */

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Insert_base

    {

      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,

				     _Equal, _H1, _H2, _Hash,

				     _RehashPolicy, _Traits>;

      using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,

					       _Equal, _H1, _H2, _Hash,

					       _Traits>;

      using value_type = typename __hashtable_base::value_type;

      using iterator = typename __hashtable_base::iterator;

      using const_iterator =  typename __hashtable_base::const_iterator;

      using size_type = typename __hashtable_base::size_type;

      using __unique_keys = typename __hashtable_base::__unique_keys;

      using __ireturn_type = typename __hashtable_base::__ireturn_type;

      using __iconv_type = typename __hashtable_base::__iconv_type;

      __hashtable&

      _M_conjure_hashtable()

      { return *(static_cast<__hashtable*>(this)); }

      __ireturn_type

      insert(const value_type& __v)

      {

	__hashtable& __h = _M_conjure_hashtable();

	return __h._M_insert(__v, __unique_keys());

      }

      iterator

      insert(const_iterator, const value_type& __v)

      { return __iconv_type()(insert(__v)); }

      void

      insert(initializer_list __l)

      { this->insert(__l.begin(), __l.end()); }

      template

	void

	insert(_InputIterator __first, _InputIterator __last);

    };

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    template

      void

      _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,

		    _RehashPolicy, _Traits>::

      insert(_InputIterator __first, _InputIterator __last)

      {

	using __rehash_type = typename __hashtable::__rehash_type;

	using __rehash_state = typename __hashtable::__rehash_state;

	using pair_type = std::pair;

	size_type __n_elt = __detail::__distance_fw(__first, __last);

	__hashtable& __h = _M_conjure_hashtable();

	__rehash_type& __rehash = __h._M_rehash_policy;

	const __rehash_state& __saved_state = __rehash._M_state();

	pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,

							__h._M_element_count,

							__n_elt);

	if (__do_rehash.first)

	  __h._M_rehash(__do_rehash.second, __saved_state);

	for (; __first != __last; ++__first)

	  __h._M_insert(*__first, __unique_keys());

      }

  /**

   *  Primary class template _Insert.

   *

   *  Select insert member functions appropriate to _Hashtable policy choices.

   */

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits,

	   bool _Constant_iterators = _Traits::__constant_iterators::value,

	   bool _Unique_keys = _Traits::__unique_keys::value>

    struct _Insert;

  /// Specialization.

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,

		   _RehashPolicy, _Traits, true, true>

    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,

			   _H1, _H2, _Hash, _RehashPolicy, _Traits>

    {

      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,

					_Equal, _H1, _H2, _Hash,

					_RehashPolicy, _Traits>;

      using value_type = typename __base_type::value_type;

      using iterator = typename __base_type::iterator;

      using const_iterator =  typename __base_type::const_iterator;

      using __unique_keys = typename __base_type::__unique_keys;

      using __hashtable = typename __base_type::__hashtable;

      using __base_type::insert;

      std::pair

      insert(value_type&& __v)

      {

	__hashtable& __h = this->_M_conjure_hashtable();

	return __h._M_insert(std::move(__v), __unique_keys());

      }

      iterator

      insert(const_iterator, value_type&& __v)

      { return insert(std::move(__v)).first; }

    };

  /// Specialization.

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,

		   _RehashPolicy, _Traits, true, false>

    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,

			   _H1, _H2, _Hash, _RehashPolicy, _Traits>

    {

      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,

					_Equal, _H1, _H2, _Hash,

					_RehashPolicy, _Traits>;

      using value_type = typename __base_type::value_type;

      using iterator = typename __base_type::iterator;

      using const_iterator =  typename __base_type::const_iterator;

      using __unique_keys = typename __base_type::__unique_keys;

      using __hashtable = typename __base_type::__hashtable;

      using __base_type::insert;

      iterator

      insert(value_type&& __v)

      {

	__hashtable& __h = this->_M_conjure_hashtable();

	return __h._M_insert(std::move(__v), __unique_keys());

      }

      iterator

      insert(const_iterator, value_type&& __v)

      { return insert(std::move(__v)); }

     };

  /// Specialization.

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits, bool _Unique_keys>

    struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,

		   _RehashPolicy, _Traits, false, _Unique_keys>

    : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,

			   _H1, _H2, _Hash, _RehashPolicy, _Traits>

    {

      using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,

				       _Equal, _H1, _H2, _Hash,

				       _RehashPolicy, _Traits>;

      using value_type = typename __base_type::value_type;

      using iterator = typename __base_type::iterator;

      using const_iterator =  typename __base_type::const_iterator;

      using __unique_keys = typename __base_type::__unique_keys;

      using __hashtable = typename __base_type::__hashtable;

      using __ireturn_type = typename __base_type::__ireturn_type;

      using __iconv_type = typename __base_type::__iconv_type;

      using __base_type::insert;

      template

	using __is_cons = std::is_constructible;

      template

	using _IFcons = std::enable_if<__is_cons<_Pair>::value>;

      template

	using _IFconsp = typename _IFcons<_Pair>::type;

      template>

	__ireturn_type

	insert(_Pair&& __v)

	{

	  __hashtable& __h = this->_M_conjure_hashtable();

	  return __h._M_emplace(__unique_keys(), std::forward<_Pair>(__v));

	}

      template>

	iterator

	insert(const_iterator, _Pair&& __v)

	{ return __iconv_type()(insert(std::forward<_Pair>(__v))); }

   };

  /**

   *  Primary class template  _Rehash_base.

   *

   *  Give hashtable the max_load_factor functions and reserve iff the

   *  rehash policy is _Prime_rehash_policy.

  */

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash,

	   typename _RehashPolicy, typename _Traits>

    struct _Rehash_base;

  /// Specialization.

  template

	   typename _ExtractKey, typename _Equal,

	   typename _H1, typename _H2, typename _Hash, typename _Traits>

    struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,

			_H1, _H2, _Hash, _Prime_rehash_policy, _Traits>

    {

      using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,

				     _Equal, _H1, _H2, _Hash,

				     _Prime_rehash_policy, _Traits>;

      float

      max_load_factor() const noexcept

      {

	const __hashtable* __this = static_cast(this);

	return __this->__rehash_policy().max_load_factor();

      }

      void

      max_load_factor(float __z)

      {

	__hashtable* __this = static_cast<__hashtable*>(this);

	__this->__rehash_policy(_Prime_rehash_policy(__z));

      }

      void

      reserve(std::size_t __n)

      {

	__hashtable* __this = static_cast<__hashtable*>(this);

	__this->rehash(__builtin_ceil(__n / max_load_factor()));

      }

    };

  /**

   *  Primary class template _Hashtable_ebo_helper.

   *

   *  Helper class using EBO when it is not forbidden, type is not

   *  final, and when it worth it, type is empty.

   */

  template

	   bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>

    struct _Hashtable_ebo_helper;

  /// Specialization using EBO.

  template

    struct _Hashtable_ebo_helper<_Nm, _Tp, true>

    : private _Tp

    {

      _Hashtable_ebo_helper() = default;

      _Hashtable_ebo_helper(const _Tp& __tp) : _Tp(__tp)

      { }

      static const _Tp&

      _S_cget(const _Hashtable_ebo_helper& __eboh)

      { return static_cast(__eboh); }

      static _Tp&

      _S_get(_Hashtable_ebo_helper& __eboh)

      { return static_cast<_Tp&>(__eboh); }

    };

  /// Specialization not using EBO.

  template

    struct _Hashtable_ebo_helper<_Nm, _Tp, false>

    {

      _Hashtable_ebo_helper() = default;

      _Hashtable_ebo_helper(const _Tp& __tp) : _M_tp(__tp)

      { }

      static const _Tp&

      _S_cget(const _Hashtable_ebo_helper& __eboh)

      { return __eboh._M_tp; }

      static _Tp&

      _S_get(_Hashtable_ebo_helper& __eboh)

      { return __eboh._M_tp; }

    private:

      _Tp _M_tp;

    };

  /**

   *  Primary class template _Local_iterator_base.

   *

   *  Base class for local iterators, used to iterate within a bucket

   *  but not between buckets.

   */

  template

	   typename _H1, typename _H2, typename _Hash,

	   bool __cache_hash_code>

    struct _Local_iterator_base;

  /**

   *  Primary class template _Hash_code_base.

   *

   *  Encapsulates two policy issues that aren't quite orthogonal.

   *   (1) the difference between using a ranged hash function and using

   *       the combination of a hash function and a range-hashing function.

   *       In the former case we don't have such things as hash codes, so

   *       we have a dummy type as placeholder.

   *   (2) Whether or not we cache hash codes.  Caching hash codes is

   *       meaningless if we have a ranged hash function.

   *

   *  We also put the key extraction objects here, for convenience.

   *  Each specialization derives from one or more of the template

   *  parameters to benefit from Ebo. This is important as this type

   *  is inherited in some cases by the _Local_iterator_base type used

   *  to implement local_iterator and const_local_iterator. As with

   *  any iterator type we prefer to make it as small as possible.

   *

   *  Primary template is unused except as a hook for specializations.

   */

  template

	   typename _H1, typename _H2, typename _Hash,

	   bool __cache_hash_code>

    struct _Hash_code_base;

  /// Specialization: ranged hash function, no caching hash codes.  H1

  /// and H2 are provided but ignored.  We define a dummy hash code type.

  template

	   typename _H1, typename _H2, typename _Hash>

    struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, false>

    : private _Hashtable_ebo_helper<0, _ExtractKey>,

      private _Hashtable_ebo_helper<1, _Hash>

    {

    private:

      using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;

      using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;

    protected:

      typedef void* 					__hash_code;

      typedef _Hash_node<_Value, false>			__node_type;

      // We need the default constructor for the local iterators.

      _Hash_code_base() = default;

      _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,

		      const _Hash& __h)

      : __ebo_extract_key(__ex), __ebo_hash(__h) { }

      __hash_code

      _M_hash_code(const _Key& __key) const

      { return 0; }

      std::size_t

      _M_bucket_index(const _Key& __k, __hash_code, std::size_t __n) const

      { return _M_ranged_hash()(__k, __n); }

      std::size_t

      _M_bucket_index(const __node_type* __p, std::size_t __n) const

      { return _M_ranged_hash()(_M_extract()(__p->_M_v), __n); }

      void

      _M_store_code(__node_type*, __hash_code) const

      { }

      void

      _M_copy_code(__node_type*, const __node_type*) const

      { }

      void

      _M_swap(_Hash_code_base& __x)

      {

	std::swap(_M_extract(), __x._M_extract());

	std::swap(_M_ranged_hash(), __x._M_ranged_hash());

      }

      const _ExtractKey&

      _M_extract() const { return __ebo_extract_key::_S_cget(*this); }

      _ExtractKey&

      _M_extract() { return __ebo_extract_key::_S_get(*this); }

      const _Hash&

      _M_ranged_hash() const { return __ebo_hash::_S_cget(*this); }

      _Hash&

      _M_ranged_hash() { return __ebo_hash::_S_get(*this); }

    };

  // No specialization for ranged hash function while caching hash codes.

  // That combination is meaningless, and trying to do it is an error.

  /// Specialization: ranged hash function, cache hash codes.  This

  /// combination is meaningless, so we provide only a declaration

  /// and no definition.

  template

	   typename _H1, typename _H2, typename _Hash>

    struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, true>;

  /// Specialization: hash function and range-hashing function, no

  /// caching of hash codes.

  /// Provides typedef and accessor required by C++ 11.

  template

	   typename _H1, typename _H2>

    struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,

			   _Default_ranged_hash, false>

    : private _Hashtable_ebo_helper<0, _ExtractKey>,

      private _Hashtable_ebo_helper<1, _H1>,

      private _Hashtable_ebo_helper<2, _H2>

    {

    private:

      using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;

      using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;

      using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;

    public:

      typedef _H1 					hasher;

      hasher

      hash_function() const

      { return _M_h1(); }

    protected:

      typedef std::size_t 				__hash_code;

      typedef _Hash_node<_Value, false>			__node_type;

      // We need the default constructor for the local iterators.

      _Hash_code_base() = default;

      _Hash_code_base(const _ExtractKey& __ex,

		      const _H1& __h1, const _H2& __h2,

		      const _Default_ranged_hash&)

      : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }

      __hash_code

      _M_hash_code(const _Key& __k) const

      { return _M_h1()(__k); }

      std::size_t

      _M_bucket_index(const _Key&, __hash_code __c, std::size_t __n) const

      { return _M_h2()(__c, __n); }

      std::size_t

      _M_bucket_index(const __node_type* __p,

		      std::size_t __n) const

      { return _M_h2()(_M_h1()(_M_extract()(__p->_M_v)), __n); }

      void

      _M_store_code(__node_type*, __hash_code) const

      { }

      void

      _M_copy_code(__node_type*, const __node_type*) const

      { }

      void

      _M_swap(_Hash_code_base& __x)

      {

	std::swap(_M_extract(), __x._M_extract());

	std::swap(_M_h1(), __x._M_h1());

	std::swap(_M_h2(), __x._M_h2());

      }

      const _ExtractKey&

      _M_extract() const { return __ebo_extract_key::_S_cget(*this); }

      _ExtractKey&

      _M_extract() { return __ebo_extract_key::_S_get(*this); }

      const _H1&

      _M_h1() const { return __ebo_h1::_S_cget(*this); }

      _H1&

      _M_h1() { return __ebo_h1::_S_get(*this); }

      const _H2&

      _M_h2() const { return __ebo_h2::_S_cget(*this); }

      _H2&

      _M_h2() { return __ebo_h2::_S_get(*this); }

    };

  /// Specialization: hash function and range-hashing function,

  /// caching hash codes.  H is provided but ignored.  Provides

  /// typedef and accessor required by C++ 11.

  template

	   typename _H1, typename _H2>

    struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,

			   _Default_ranged_hash, true>

    : private _Hashtable_ebo_helper<0, _ExtractKey>,

      private _Hashtable_ebo_helper<1, _H1>,

      private _Hashtable_ebo_helper<2, _H2>

    {

    private:

      // Gives access to _M_h2() to the local iterator implementation.

      friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,

					 _Default_ranged_hash, true>;

      using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;

      using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;

      using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;

    public:

      typedef _H1 					hasher;

      hasher

      hash_function() const

      { return _M_h1(); }

    protected:

      typedef std::size_t 				__hash_code;

      typedef _Hash_node<_Value, true>			__node_type;

      _Hash_code_base(const _ExtractKey& __ex,

		      const _H1& __h1, const _H2& __h2,

		      const _Default_ranged_hash&)

      : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }

      __hash_code

      _M_hash_code(const _Key& __k) const

      { return _M_h1()(__k); }

      std::size_t

      _M_bucket_index(const _Key&, __hash_code __c,

		      std::size_t __n) const

      { return _M_h2()(__c, __n); }

      std::size_t

      _M_bucket_index(const __node_type* __p, std::size_t __n) const

      { return _M_h2()(__p->_M_hash_code, __n); }

      void

      _M_store_code(__node_type* __n, __hash_code __c) const

      { __n->_M_hash_code = __c; }

      void

      _M_copy_code(__node_type* __to, const __node_type* __from) const

      { __to->_M_hash_code = __from->_M_hash_code; }