0
  +   ˆl–Ü4ý(”†»â‚À¹q ©‹FÿÁ„y§Ù_†I|¥�+ÁÀ ?÷     // hashtable.h header -*- C++ -*-

// Copyright (C) 2007-2021 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
// <http://www.gnu.org/licenses/>.

/** @file bits/hashtable.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_H
#define _HASHTABLE_H 1

#pragma GCC system_header

#include <bits/hashtable_policy.h>
#include <bits/enable_special_members.h>
#if __cplusplus > 201402L
# include <bits/node_handle.h>
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/// @cond undocumented

  template<typename _Tp, typename _Hash>
    using __cache_default
      =  __not_<__and_<// Do not cache for fast hasher.
		       __is_fast_hash<_Hash>,
		       // Mandatory to have erase not throwing.
		       __is_nothrow_invocable<const _Hash&, const _Tp&>>>;

  // Helper to conditionally delete the default constructor.
  // The _Hash_node_base type is used to distinguish this specialization
  // from any other potentially-overlapping subobjects of the hashtable.
  template<typename _Equal, typename _Hash, typename _Allocator>
    using _Hashtable_enable_default_ctor
      = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
				       is_default_constructible<_Hash>,
				       is_default_constructible<_Allocator>>{},
				    __detail::_Hash_node_base>;

  /**
   *  Primary class template _Hashtable.
   *
   *  @ingroup hashtable-detail
   *
   *  @tparam _Value  CopyConstructible type.
   *
   *  @tparam _Key    CopyConstructible type.
   *
   *  @tparam _Alloc  An allocator type
   *  ([lib.allocator.requirements]) whose _Alloc::value_type is
   *  _Value.  As a conforming extension, we allow for
   *  _Alloc::value_type != _Value.
   *
   *  @tparam _ExtractKey  Function object that takes an object of type
   *  _Value and returns a value of type _Key.
   *
   *  @tparam _Equal  Function object that takes two objects of type k
   *  and returns a bool-like value that is true if the two objects
   *  are considered equal.
   *
   *  @tparam _Hash  The hash function. A unary function object with
   *  argument type _Key and result type size_t. Return values should
   *  be distributed over the entire range [0, numeric_limits<size_t>:::max()].
   *
   *  @tparam _RangeHash  The range-hashing function (in the terminology of
   *  Tavori and Dreizin).  A binary function object whose argument
   *  types and result type are all size_t.  Given arguments r and N,
   *  the return value is in the range [0, N).
   *
   *  @tparam _Unused  Not used.
   *
   *  @tparam _RehashPolicy  Policy class with three members, all of
   *  which govern the bucket count. _M_next_bkt(n) returns a bucket
   *  count no smaller than n.  _M_bkt_for_elements(n) returns a
   *  bucket count appropriate for an element count of n.
   *  _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
   *  current bucket count is n_bkt and the current element count is
   *  n_elt, we need to increase the bucket count for