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_BASE_TYPE_HPP
10#define BOOST_MULTI_INDEX_DETAIL_BASE_TYPE_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/detail/workaround.hpp>
18#include <boost/mpl/at.hpp>
19#include <boost/mpl/apply.hpp>
20#include <boost/mpl/size.hpp>
21#include <boost/multi_index/detail/index_base.hpp>
22#include <boost/multi_index/detail/is_index_list.hpp>
23#include <boost/static_assert.hpp>
24
25namespace boost{
26
27namespace multi_index{
28
29namespace detail{
30
31/* MPL machinery to construct a linear hierarchy of indices out of
32 * a index list.
33 */
34
35struct index_applier
36{
37 template<typename IndexSpecifierMeta,typename SuperMeta>
38 struct apply
39 {
40 typedef typename IndexSpecifierMeta::type index_specifier;
41 typedef typename index_specifier::
42 BOOST_NESTED_TEMPLATE index_class<SuperMeta>::type type;
43 };
44};
45
46template<int N,typename Value,typename IndexSpecifierList,typename Allocator>
47struct nth_layer
48{
49 BOOST_STATIC_CONSTANT(int,length=mpl::size<IndexSpecifierList>::value);
50
51 typedef typename mpl::eval_if_c<
52 N==length,
53 mpl::identity<index_base<Value,IndexSpecifierList,Allocator> >,
54 mpl::apply2<
55 index_applier,
56 mpl::at_c<IndexSpecifierList,N>,
57 nth_layer<N+1,Value,IndexSpecifierList,Allocator>
58 >
59 >::type type;
60};
61
62template<typename Value,typename IndexSpecifierList,typename Allocator>
63struct multi_index_base_type:nth_layer<0,Value,IndexSpecifierList,Allocator>
64{
65 BOOST_STATIC_ASSERT(detail::is_index_list<IndexSpecifierList>::value);
66};
67
68} /* namespace multi_index::detail */
69
70} /* namespace multi_index */
71
72} /* namespace boost */
73
74#endif
75