/* Copyright 2003-2005 Joaquín M López Muñoz.

  * 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>

 namespace boost{

 namespace multi_index{

 namespace detail{

 /* A utility class 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:private noncopyable

 {

   header_holder():member(final().allocate_node()){}

   ~header_holder(){final().deallocate_node(member);}

   NodeType* member;

 private:

   Final& final(){return *static_cast<Final*>(this);}

 };

 } /* namespace multi_index::detail */

 } /* namespace multi_index */

 } /* namespace boost */

 #endif