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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2009, 2011 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/>.

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice

// and this permission notice appear in supporting documentation. None

// of the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied

// warranty.

/**

 * @file hash_eq_fn.hpp

 * Contains 2 eqivalence functions, one employing a hash value,

 * and one ignoring it.

 */

#ifndef PB_DS_HASH_EQ_FN_HPP

#define PB_DS_HASH_EQ_FN_HPP

#include <utility>

#include <debug/debug.h>

namespace __gnu_pbds

{

  namespace detail

  {

    /// Primary template.

    template<typename Key, typename Eq_Fn, typename _Alloc, bool Store_Hash>

      struct hash_eq_fn;

    /// Specialization 1 - The client requests that hash values not be stored.

    template<typename Key, typename Eq_Fn, typename _Alloc>

    struct hash_eq_fn<Key, Eq_Fn, _Alloc, false> : public Eq_Fn

    {

      typedef Eq_Fn                                        eq_fn_base;

      typedef typename _Alloc::template rebind<Key>::other key_allocator;

      typedef typename key_allocator::const_reference      key_const_reference;

      hash_eq_fn() { }

      hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }

      bool

      operator()(key_const_reference r_lhs_key,

                 key_const_reference r_rhs_key) const

      { return eq_fn_base::operator()(r_lhs_key, r_rhs_key); }

      void

      swap(const hash_eq_fn& other)

      { std::swap((Eq_Fn&)(*this), (Eq_Fn&)other); }

    };

    /// Specialization 2 - The client requests that hash values be stored.

    template<typename Key, class Eq_Fn, class _Alloc>

    struct hash_eq_fn<Key, Eq_Fn, _Alloc, true> : public Eq_Fn

    {

      typedef typename _Alloc::size_type                   size_type;

      typedef Eq_Fn                                        eq_fn_base;

      typedef typename _Alloc::template rebind<Key>::other key_allocator;

      typedef typename key_allocator::const_reference      key_const_reference;

      hash_eq_fn() { }

      hash_eq_fn(const Eq_Fn& r_eq_fn) : Eq_Fn(r_eq_fn) { }

      bool

      operator()(key_const_reference r_lhs_key, size_type lhs_hash,

                 key_const_reference r_rhs_key, size_type rhs_hash) const

      {

        _GLIBCXX_DEBUG_ASSERT(!eq_fn_base::operator()(r_lhs_key, r_rhs_key)

                              || lhs_hash == rhs_hash);

        return (lhs_hash == rhs_hash &&

                eq_fn_base::operator()(r_lhs_key, r_rhs_key));

      }

      void

      swap(const hash_eq_fn& other)

      { std::swap((Eq_Fn&)(*this), (Eq_Fn&)(other)); }

    };

  } // namespace detail

} // namespace __gnu_pbds

#endif