/* Copyright 2003-2008 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_HEADER_HOLDER_HPP
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#define BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_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/noncopyable.hpp>
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namespace boost{
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namespace multi_index{
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namespace detail{
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/* A utility class used to hold a pointer to the header node.
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* The base from member idiom is used because index classes, which are
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* superclasses of multi_index_container, need this header in construction
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* time. The allocation is made by the allocator of the multi_index_container
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* class --hence, this allocator needs also be stored resorting
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* to the base from member trick.
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*/
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template<typename NodeTypePtr,typename Final>
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struct header_holder:private noncopyable
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{
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header_holder():member(final().allocate_node()){}
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~header_holder(){final().deallocate_node(&*member);}
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NodeTypePtr member;
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private:
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Final& final(){return *static_cast<Final*>(this);}
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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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