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_TAG_HPP
10#define BOOST_MULTI_INDEX_TAG_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/multi_index/detail/no_duplicate_tags.hpp>
18#include <boost/mpl/identity.hpp>
19#include <boost/mpl/transform.hpp>
20#include <boost/mpl/vector.hpp>
21#include <boost/preprocessor/facilities/intercept.hpp>
22#include <boost/preprocessor/repetition/enum_binary_params.hpp>
23#include <boost/preprocessor/repetition/enum_params.hpp>
24#include <boost/static_assert.hpp>
25#include <boost/type_traits/is_base_and_derived.hpp>
26
27/* A wrapper of mpl::vector used to hide MPL from the user.
28 * tag contains types used as tag names for indices in get() functions.
29 */
30
31/* This user_definable macro limits the number of elements of a tag;
32 * useful for shortening resulting symbol names (MSVC++ 6.0, for instance,
33 * has problems coping with very long symbol names.)
34 */
35
36#if !defined(BOOST_MULTI_INDEX_LIMIT_TAG_SIZE)
37#define BOOST_MULTI_INDEX_LIMIT_TAG_SIZE BOOST_MPL_LIMIT_VECTOR_SIZE
38#endif
39
40#if BOOST_MULTI_INDEX_LIMIT_TAG_SIZE<BOOST_MPL_LIMIT_VECTOR_SIZE
41#define BOOST_MULTI_INDEX_TAG_SIZE BOOST_MULTI_INDEX_LIMIT_TAG_SIZE
42#else
43#define BOOST_MULTI_INDEX_TAG_SIZE BOOST_MPL_LIMIT_VECTOR_SIZE
44#endif
45
46namespace boost{
47
48namespace multi_index{
49
50namespace detail{
51
52struct tag_marker{};
53
54template<typename T>
55struct is_tag
56{
57 BOOST_STATIC_CONSTANT(bool,value=(is_base_and_derived<tag_marker,T>::value));
58};
59
60} /* namespace multi_index::detail */
61
62template<
63 BOOST_PP_ENUM_BINARY_PARAMS(
64 BOOST_MULTI_INDEX_TAG_SIZE,
65 typename T,
66 =mpl::na BOOST_PP_INTERCEPT)
67>
68struct tag:private detail::tag_marker
69{
70 /* The mpl::transform pass produces shorter symbols (without
71 * trailing mpl::na's.)
72 */
73
74 typedef typename mpl::transform<
75 mpl::vector<BOOST_PP_ENUM_PARAMS(BOOST_MULTI_INDEX_TAG_SIZE,T)>,
76 mpl::identity<mpl::_1>
77 >::type type;
78
79 BOOST_STATIC_ASSERT(detail::no_duplicate_tags<type>::value);
80};
81
82} /* namespace multi_index */
83
84} /* namespace boost */
85
86#undef BOOST_MULTI_INDEX_TAG_SIZE
87
88#endif
89