williamr@2: /* Copyright 2003-2005 Joaquín M López Muñoz.
williamr@2:  * Distributed under the Boost Software License, Version 1.0.
williamr@2:  * (See accompanying file LICENSE_1_0.txt or copy at
williamr@2:  * http://www.boost.org/LICENSE_1_0.txt)
williamr@2:  *
williamr@2:  * See http://www.boost.org/libs/multi_index for library home page.
williamr@2:  */
williamr@2: 
williamr@2: #ifndef BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_HPP
williamr@2: #define BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_HPP
williamr@2: 
williamr@2: #if defined(_MSC_VER)&&(_MSC_VER>=1200)
williamr@2: #pragma once
williamr@2: #endif
williamr@2: 
williamr@2: #include <boost/noncopyable.hpp>
williamr@2: 
williamr@2: namespace boost{
williamr@2: 
williamr@2: namespace multi_index{
williamr@2: 
williamr@2: namespace detail{
williamr@2: 
williamr@2: /* A utility class used to hold a pointer to the header node.
williamr@2:  * The base from member idiom is used because index classes, which are
williamr@2:  * superclasses of multi_index_container, need this header in construction
williamr@2:  * time. The allocation is made by the allocator of the multi_index_container
williamr@2:  * class --hence, this allocator needs also be stored resorting
williamr@2:  * to the base from member trick.
williamr@2:  */
williamr@2: 
williamr@2: template<typename NodeType,typename Final>
williamr@2: struct header_holder:private noncopyable
williamr@2: {
williamr@2:   header_holder():member(final().allocate_node()){}
williamr@2:   ~header_holder(){final().deallocate_node(member);}
williamr@2: 
williamr@2:   NodeType* member;
williamr@2: 
williamr@2: private:
williamr@2:   Final& final(){return *static_cast<Final*>(this);}
williamr@2: };
williamr@2: 
williamr@2: } /* namespace multi_index::detail */
williamr@2: 
williamr@2: } /* namespace multi_index */
williamr@2: 
williamr@2: } /* namespace boost */
williamr@2: 
williamr@2: #endif