1/* Copyright 2003-2013 Joaquin M Lopez Munoz.
2 * Distributed under the Boost Software License, Version 1.0.
3 * (See accompanying file LICENSE_1_0.txt or copy at
4 * http://www.boost.org/LICENSE_1_0.txt)
5 *
6 * See http://www.boost.org/libs/multi_index for library home page.
7 */
8
9#ifndef BOOST_MULTI_INDEX_DETAIL_ORD_INDEX_ARGS_HPP
10#define BOOST_MULTI_INDEX_DETAIL_ORD_INDEX_ARGS_HPP
11
12#if defined(_MSC_VER)
13#pragma once
14#endif
15
16#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
17#include <boost/mpl/aux_/na.hpp>
18#include <boost/mpl/eval_if.hpp>
19#include <boost/mpl/identity.hpp>
20#include <boost/mpl/if.hpp>
21#include <boost/multi_index/tag.hpp>
22#include <boost/static_assert.hpp>
23#include <boost/type_traits/is_same.hpp>
24#include <functional>
25
26namespace boost{
27
28namespace multi_index{
29
30namespace detail{
31
32/* Oredered index specifiers can be instantiated in two forms:
33 *
34 * (ordered_unique|ordered_non_unique)<
35 * KeyFromValue,Compare=std::less<KeyFromValue::result_type> >
36 * (ordered_unique|ordered_non_unique)<
37 * TagList,KeyFromValue,Compare=std::less<KeyFromValue::result_type> >
38 *
39 * index_args implements the machinery to accept this argument-dependent
40 * polymorphism.
41 */
42
43template<typename KeyFromValue>
44struct index_args_default_compare
45{
46 typedef std::less<typename KeyFromValue::result_type> type;
47};
48
49template<typename Arg1,typename Arg2,typename Arg3>
50struct ordered_index_args
51{
52 typedef is_tag<Arg1> full_form;
53
54 typedef typename mpl::if_<
55 full_form,
56 Arg1,
57 tag< > >::type tag_list_type;
58 typedef typename mpl::if_<
59 full_form,
60 Arg2,
61 Arg1>::type key_from_value_type;
62 typedef typename mpl::if_<
63 full_form,
64 Arg3,
65 Arg2>::type supplied_compare_type;
66 typedef typename mpl::eval_if<
67 mpl::is_na<supplied_compare_type>,
68 index_args_default_compare<key_from_value_type>,
69 mpl::identity<supplied_compare_type>
70 >::type compare_type;
71
72 BOOST_STATIC_ASSERT(is_tag<tag_list_type>::value);
73 BOOST_STATIC_ASSERT(!mpl::is_na<key_from_value_type>::value);
74 BOOST_STATIC_ASSERT(!mpl::is_na<compare_type>::value);
75};
76
77} /* namespace multi_index::detail */
78
79} /* namespace multi_index */
80
81} /* namespace boost */
82
83#endif
84