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- /* Copyright 2003-2013 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_DETAIL_NO_DUPLICATE_TAGS_HPP
- #define BOOST_MULTI_INDEX_DETAIL_NO_DUPLICATE_TAGS_HPP
- #if defined(_MSC_VER)
- #pragma once
- #endif
- #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
- #include <boost/mpl/fold.hpp>
- #include <boost/mpl/set/set0.hpp>
- namespace boost{
- namespace multi_index{
- namespace detail{
- /* no_duplicate_tags check at compile-time that a tag list
- * has no duplicate tags.
- * The algorithm deserves some explanation: tags
- * are sequentially inserted into a mpl::set if they were
- * not already present. Due to the magic of mpl::set
- * (mpl::has_key is contant time), this operation takes linear
- * time, and even MSVC++ 6.5 handles it gracefully (other obvious
- * solutions are quadratic.)
- */
- struct duplicate_tag_mark{};
- struct duplicate_tag_marker
- {
- template <typename MplSet,typename Tag>
- struct apply
- {
- typedef mpl::s_item<
- typename mpl::if_<mpl::has_key<MplSet,Tag>,duplicate_tag_mark,Tag>::type,
- MplSet
- > type;
- };
- };
- template<typename TagList>
- struct no_duplicate_tags
- {
- typedef typename mpl::fold<
- TagList,
- mpl::set0<>,
- duplicate_tag_marker
- >::type aux;
-
- BOOST_STATIC_CONSTANT(
- bool,value=!(mpl::has_key<aux,duplicate_tag_mark>::value));
- };
- /* Variant for an index list: duplication is checked
- * across all the indices.
- */
- struct duplicate_tag_list_marker
- {
- template <typename MplSet,typename Index>
- struct apply:mpl::fold<
- BOOST_DEDUCED_TYPENAME Index::tag_list,
- MplSet,
- duplicate_tag_marker>
- {
- };
- };
- template<typename IndexList>
- struct no_duplicate_tags_in_index_list
- {
- typedef typename mpl::fold<
- IndexList,
- mpl::set0<>,
- duplicate_tag_list_marker
- >::type aux;
-
- BOOST_STATIC_CONSTANT(
- bool,value=!(mpl::has_key<aux,duplicate_tag_mark>::value));
- };
- } /* namespace multi_index::detail */
- } /* namespace multi_index */
- } /* namespace boost */
- #endif
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