multi_index/detail/value_compare.hpp

0001 /* Copyright 2003-2015 Joaquin M Lopez Munoz.
0002  * Distributed under the Boost Software License, Version 1.0.
0003  * (See accompanying file LICENSE_1_0.txt or copy at
0004  * http://www.boost.org/LICENSE_1_0.txt)
0005  *
0006  * See http://www.boost.org/libs/multi_index for library home page.
0007  */
0008
0009 #ifndef BOOST_MULTI_INDEX_DETAIL_VALUE_COMPARE_HPP
0010 #define BOOST_MULTI_INDEX_DETAIL_VALUE_COMPARE_HPP
0011
0012 #if defined(_MSC_VER)
0013 #pragma once
0014 #endif
0015
0016 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
0017 #include <boost/call_traits.hpp>
0018
0019 namespace boost{
0020
0021 namespace multi_index{
0022
0023 namespace detail{
0024
0025 template<typename Value,typename KeyFromValue,typename Compare>
0026 struct value_comparison
0027 {
0028   typedef Value first_argument_type;
0029   typedef Value second_argument_type;
0030   typedef bool  result_type;
0031
0032   value_comparison(
0033     const KeyFromValue& key_=KeyFromValue(),const Compare& comp_=Compare()):
0034     key(key_),comp(comp_)
0035   {
0036   }
0037
0038   bool operator()(
0039     typename call_traits<Value>::param_type x,
0040     typename call_traits<Value>::param_type y)const
0041   {
0042     return comp(key(x),key(y));
0043   }
0044
0045 private:
0046   KeyFromValue key;
0047   Compare      comp;
0048 };
0049
0050 } /* namespace multi_index::detail */
0051
0052 } /* namespace multi_index */
0053
0054 } /* namespace boost */
0055
0056 #endif