boost/multi_index/tag.hpp
/* Copyright 2003-2008 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_TAG_HPP
#define BOOST_MULTI_INDEX_TAG_HPP
#if defined(_MSC_VER)&&(_MSC_VER>=1200)
#pragma once
#endif
#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
#include <boost/multi_index/detail/no_duplicate_tags.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/mpl/transform.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/static_assert.hpp>
#include <boost/type_traits/is_base_and_derived.hpp>
/* A wrapper of mpl::vector used to hide MPL from the user.
* tag contains types used as tag names for indices in get() functions.
*/
/* This user_definable macro limits the number of elements of a tag;
* useful for shortening resulting symbol names (MSVC++ 6.0, for instance,
* has problems coping with very long symbol names.)
*/
#if !defined(BOOST_MULTI_INDEX_LIMIT_TAG_SIZE)
#if defined(BOOST_MSVC)&&(BOOST_MSVC<1300)
#define BOOST_MULTI_INDEX_LIMIT_TAG_SIZE 3
#else
#define BOOST_MULTI_INDEX_LIMIT_TAG_SIZE BOOST_MPL_LIMIT_VECTOR_SIZE
#endif
#endif
#if BOOST_MULTI_INDEX_LIMIT_TAG_SIZE<BOOST_MPL_LIMIT_VECTOR_SIZE
#define BOOST_MULTI_INDEX_TAG_SIZE BOOST_MULTI_INDEX_LIMIT_TAG_SIZE
#else
#define BOOST_MULTI_INDEX_TAG_SIZE BOOST_MPL_LIMIT_VECTOR_SIZE
#endif
namespace boost{
namespace multi_index{
namespace detail{
struct tag_marker{};
template<typename T>
struct is_tag
{
BOOST_STATIC_CONSTANT(bool,value=(is_base_and_derived<tag_marker,T>::value));
};
} /* namespace multi_index::detail */
template<
BOOST_PP_ENUM_BINARY_PARAMS(
BOOST_MULTI_INDEX_TAG_SIZE,
typename T,
=mpl::na BOOST_PP_INTERCEPT)
>
struct tag:private detail::tag_marker
{
/* The mpl::transform pass produces shorter symbols (without
* trailing mpl::na's.)
*/
typedef typename mpl::transform<
mpl::vector<BOOST_PP_ENUM_PARAMS(BOOST_MULTI_INDEX_TAG_SIZE,T)>,
mpl::identity<mpl::_1>
>::type type;
BOOST_STATIC_ASSERT(detail::no_duplicate_tags<type>::value);
};
} /* namespace multi_index */
} /* namespace boost */
#undef BOOST_MULTI_INDEX_TAG_SIZE
#endif