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 46 namespace boost{ 47 48 namespace multi_index{ 49 50 namespace detail{ 51 52 struct tag_marker{}; 53 54 template<typename T> 55 struct 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 62 template< 63 BOOST_PP_ENUM_BINARY_PARAMS( 64 BOOST_MULTI_INDEX_TAG_SIZE, 65 typename T, 66 =mpl::na BOOST_PP_INTERCEPT) 67 > 68 struct 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