98 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			98 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
/* Copyright 2003-2013 Joaquin M Lopez Munoz.
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 * Distributed under the Boost Software License, Version 1.0.
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 * (See accompanying file LICENSE_1_0.txt or copy at
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 * http://www.boost.org/LICENSE_1_0.txt)
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 *
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 * See http://www.boost.org/libs/multi_index for library home page.
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 */
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#ifndef BOOST_MULTI_INDEX_DETAIL_NO_DUPLICATE_TAGS_HPP
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#define BOOST_MULTI_INDEX_DETAIL_NO_DUPLICATE_TAGS_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
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#include <boost/mpl/fold.hpp>
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#include <boost/mpl/set/set0.hpp>
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namespace boost{
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namespace multi_index{
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namespace detail{
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/* no_duplicate_tags check at compile-time that a tag list
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 * has no duplicate tags.
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 * The algorithm deserves some explanation: tags
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 * are sequentially inserted into a mpl::set if they were
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 * not already present. Due to the magic of mpl::set
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 * (mpl::has_key is contant time), this operation takes linear
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 * time, and even MSVC++ 6.5 handles it gracefully (other obvious
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 * solutions are quadratic.)
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 */
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struct duplicate_tag_mark{};
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struct duplicate_tag_marker
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{
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  template <typename MplSet,typename Tag>
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  struct apply
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  {
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    typedef mpl::s_item<
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      typename mpl::if_<mpl::has_key<MplSet,Tag>,duplicate_tag_mark,Tag>::type,
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      MplSet
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    > type;
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  };
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};
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template<typename TagList>
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struct no_duplicate_tags
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{
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  typedef typename mpl::fold<
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    TagList,
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    mpl::set0<>,
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    duplicate_tag_marker
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  >::type aux;
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  BOOST_STATIC_CONSTANT(
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    bool,value=!(mpl::has_key<aux,duplicate_tag_mark>::value));
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};
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/* Variant for an index list: duplication is checked
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 * across all the indices.
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 */
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struct duplicate_tag_list_marker
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{
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  template <typename MplSet,typename Index>
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  struct apply:mpl::fold<
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    BOOST_DEDUCED_TYPENAME Index::tag_list,
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    MplSet,
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    duplicate_tag_marker>
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  {
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  };
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};
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template<typename IndexList>
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struct no_duplicate_tags_in_index_list
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{
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  typedef typename mpl::fold<
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    IndexList,
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    mpl::set0<>,
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    duplicate_tag_list_marker
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  >::type aux;
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  BOOST_STATIC_CONSTANT(
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    bool,value=!(mpl::has_key<aux,duplicate_tag_mark>::value));
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};
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} /* namespace multi_index::detail */
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} /* namespace multi_index */
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} /* namespace boost */
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#endif
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