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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2007, 2009 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 list_update_policy.hpp

 * Contains policies for list update containers.

 */

#ifndef PB_DS_LU_POLICY_HPP

#define PB_DS_LU_POLICY_HPP

#include <cstdlib>

#include <ext/pb_ds/detail/list_update_policy/counter_lu_metadata.hpp>

namespace __gnu_pbds

{

  // A null type that means that each link in a list-based container

  // does not actually need metadata.

  struct null_lu_metadata

  { };

#define PB_DS_CLASS_T_DEC template<typename Allocator>

#define PB_DS_CLASS_C_DEC move_to_front_lu_policy<Allocator>

  // A list-update policy that unconditionally moves elements to the

  // front of the list.

  template<typename Allocator = std::allocator<char> >

  class move_to_front_lu_policy

  {

  public:

    typedef Allocator allocator_type;

    // Metadata on which this functor operates.

    typedef null_lu_metadata metadata_type;

    // Reference to metadata on which this functor operates.

    typedef typename allocator_type::template rebind<metadata_type>::other metadata_rebind;

    typedef typename metadata_rebind::reference metadata_reference;

    // Creates a metadata object.

    metadata_type

    operator()() const;

    // Decides whether a metadata object should be moved to the front

    // of the list.

    inline bool

    operator()(metadata_reference r_metadata) const;

  private:

    static null_lu_metadata s_metadata;

  };

#include <ext/pb_ds/detail/list_update_policy/mtf_lu_policy_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

#define PB_DS_CLASS_T_DEC template<size_t Max_Count, class Allocator>

#define PB_DS_CLASS_C_DEC counter_lu_policy<Max_Count, Allocator>

  // A list-update policy that moves elements to the front of the list

  // based on the counter algorithm.

  template<size_t Max_Count = 5, typename Allocator = std::allocator<char> >

  class counter_lu_policy

  : private detail::counter_lu_policy_base<typename Allocator::size_type>

  {

  public:

    typedef Allocator allocator_type;

    enum

      {

        max_count = Max_Count

      };

    typedef typename allocator_type::size_type size_type;

    // Metadata on which this functor operates.

    typedef detail::counter_lu_metadata<size_type> metadata_type;

    // Reference to metadata on which this functor operates.

    typedef typename Allocator::template rebind<metadata_type>::other metadata_rebind;

    typedef typename metadata_rebind::reference metadata_reference;

    // Creates a metadata object.

    metadata_type

    operator()() const;

    // Decides whether a metadata object should be moved to the front

    // of the list.

    bool

    operator()(metadata_reference r_metadata) const;

  private:

    typedef detail::counter_lu_policy_base<typename Allocator::size_type> base_type;

  };

#include <ext/pb_ds/detail/list_update_policy/counter_lu_policy_imp.hpp>

#undef PB_DS_CLASS_T_DEC

#undef PB_DS_CLASS_C_DEC

} // namespace __gnu_pbds

#endif