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1 | /* Copyright 2003-2008 Joaquin M Lopez Munoz. | |
2 | * Distributed under the Boost Software License, Version 1.0. | |
3 | * (See accompanying file LICENSE_1_0.txt or copy at | |
4 | * http://www.boost.org/LICENSE_1_0.txt) | |
5 | * | |
6 | * See http://www.boost.org/libs/multi_index for library home page. | |
7 | */ | |
8 | ||
9 | #ifndef BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_HPP | |
10 | #define BOOST_MULTI_INDEX_DETAIL_HEADER_HOLDER_HPP | |
11 | ||
12 | #if defined(_MSC_VER) | |
13 | #pragma once | |
14 | #endif | |
15 | ||
16 | #include <boost/noncopyable.hpp> | |
17 | ||
18 | namespace boost{ | |
19 | ||
20 | namespace multi_index{ | |
21 | ||
22 | namespace detail{ | |
23 | ||
24 | /* A utility class used to hold a pointer to the header node. | |
25 | * The base from member idiom is used because index classes, which are | |
26 | * superclasses of multi_index_container, need this header in construction | |
27 | * time. The allocation is made by the allocator of the multi_index_container | |
28 | * class --hence, this allocator needs also be stored resorting | |
29 | * to the base from member trick. | |
30 | */ | |
31 | ||
32 | template<typename NodeTypePtr,typename Final> | |
33 | struct header_holder:private noncopyable | |
34 | { | |
35 | header_holder():member(final().allocate_node()){} | |
36 | ~header_holder(){final().deallocate_node(&*member);} | |
37 | ||
38 | NodeTypePtr member; | |
39 | ||
40 | private: | |
41 | Final& final(){return *static_cast<Final*>(this);} | |
42 | }; | |
43 | ||
44 | } /* namespace multi_index::detail */ | |
45 | ||
46 | } /* namespace multi_index */ | |
47 | ||
48 | } /* namespace boost */ | |
49 | ||
50 | #endif |