/* Copyright 2003-2013 Joaquin M Lopez Munoz.
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 *
 * See http://www.boost.org/libs/multi_index for library home page.
 */

#ifndef BOOST_MULTI_INDEX_DETAIL_VALUE_COMPARE_HPP
#define BOOST_MULTI_INDEX_DETAIL_VALUE_COMPARE_HPP

#if defined(_MSC_VER)
#pragma once
#endif

#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
#include <boost/call_traits.hpp>
#include <functional>

namespace boost{

namespace multi_index{

namespace detail{

template<typename Value,typename KeyFromValue,typename Compare>
struct value_comparison:std::binary_function<Value,Value,bool>
{
  value_comparison(
    const KeyFromValue& key_=KeyFromValue(),const Compare& comp_=Compare()):
    key(key_),comp(comp_)
  {
  }

  bool operator()(
    typename call_traits<Value>::param_type x,
    typename call_traits<Value>::param_type y)const
  {
    return comp(key(x),key(y));
  }

private:
  KeyFromValue key;
  Compare      comp;
};

} /* namespace multi_index::detail */

} /* namespace multi_index */

} /* namespace boost */

#endif
