boost/multi_index/detail/header_holder.hpp
/* Copyright 2003-2005 Joaqu�n M L�pez Mu�oz.
* 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_HEADER_HOLDER_HPP
#define BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_HPP
#if defined(_MSC_VER)&&(_MSC_VER>=1200)
#pragma once
#endif
#include <boost/noncopyable.hpp>
#include <boost/utility/base_from_member.hpp>
namespace boost{
namespace multi_index{
namespace detail{
/* An utility class derived from base_from_member used to hold
* a pointer to the header node. The base from member idiom is used
* because index classes, which are superclasses of multi_index_container,
* need this header in construction time.
* The allocation is made by the allocator of the multi_index_container
* class --hence, this allocator needs also be stored resorting
* to the base from member trick.
*/
template<typename NodeType,typename Final>
struct header_holder:base_from_member<NodeType*>,private noncopyable
{
header_holder():super(final().allocate_node()){}
~header_holder(){final().deallocate_node(super::member);}
private:
typedef base_from_member<NodeType*> super;
Final& final(){return *static_cast<Final*>(this);}
};
} /* namespace multi_index::detail */
} /* namespace multi_index */
} /* namespace boost */
#endif