1//-----------------------------------------------------------------------------
2// boost variant/detail/backup_holder.hpp header file
3// See http://www.boost.org for updates, documentation, and revision history.
4//-----------------------------------------------------------------------------
5//
6// Copyright (c) 2003
7// Eric Friedman
8//
9// Distributed under the Boost Software License, Version 1.0. (See
10// accompanying file LICENSE_1_0.txt or copy at
11// http://www.boost.org/LICENSE_1_0.txt)
12
13#ifndef BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP
14#define BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP
15
16#include <boost/config.hpp>
17#include <boost/assert.hpp>
18
19namespace boost {
20namespace detail { namespace variant {
21
22template <typename T>
23class backup_holder
24{
25private: // representation
26
27 T* backup_;
28
29public: // structors
30
31 ~backup_holder() BOOST_NOEXCEPT
32 {
33 delete backup_;
34 }
35
36 explicit backup_holder(T* backup) BOOST_NOEXCEPT
37 : backup_(backup)
38 {
39 }
40
41 backup_holder(const backup_holder&);
42
43public: // modifiers
44
45 backup_holder& operator=(const backup_holder& rhs)
46 {
47 *backup_ = rhs.get();
48 return *this;
49 }
50
51 backup_holder& operator=(const T& rhs)
52 {
53 *backup_ = rhs;
54 return *this;
55 }
56
57 void swap(backup_holder& rhs) BOOST_NOEXCEPT
58 {
59 T* tmp = rhs.backup_;
60 rhs.backup_ = this->backup_;
61 this->backup_ = tmp;
62 }
63
64public: // queries
65
66 T& get() BOOST_NOEXCEPT
67 {
68 return *backup_;
69 }
70
71 const T& get() const BOOST_NOEXCEPT
72 {
73 return *backup_;
74 }
75
76};
77
78template <typename T>
79backup_holder<T>::backup_holder(const backup_holder&)
80 : backup_(0)
81{
82 // not intended for copy, but do not want to prohibit syntactically
83 BOOST_ASSERT(false);
84}
85
86template <typename T>
87void swap(backup_holder<T>& lhs, backup_holder<T>& rhs) BOOST_NOEXCEPT
88{
89 lhs.swap(rhs);
90}
91
92}} // namespace detail::variant
93} // namespace boost
94
95#endif // BOOST_VARIANT_DETAIL_BACKUP_HOLDER_HPP
96