1 | //----------------------------------------------------------------------------- |
2 | // boost aligned_storage.hpp header file |
3 | // See http://www.boost.org for updates, documentation, and revision history. |
4 | //----------------------------------------------------------------------------- |
5 | // |
6 | // Copyright (c) 2002-2003 |
7 | // Eric Friedman, Itay Maman |
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_TT_ALIGNED_STORAGE_HPP |
14 | #define BOOST_TT_ALIGNED_STORAGE_HPP |
15 | |
16 | #include <cstddef> // for std::size_t |
17 | |
18 | #include <boost/config.hpp> |
19 | #include <boost/detail/workaround.hpp> |
20 | #include <boost/type_traits/alignment_of.hpp> |
21 | #include <boost/type_traits/type_with_alignment.hpp> |
22 | #include <boost/type_traits/is_pod.hpp> |
23 | #include <boost/type_traits/conditional.hpp> |
24 | |
25 | namespace boost { |
26 | |
27 | namespace detail { namespace aligned_storage { |
28 | |
29 | BOOST_STATIC_CONSTANT( |
30 | std::size_t |
31 | , alignment_of_max_align = ::boost::alignment_of<boost::detail::max_align>::value |
32 | ); |
33 | |
34 | // |
35 | // To be TR1 conforming this must be a POD type: |
36 | // |
37 | template < |
38 | std::size_t size_ |
39 | , std::size_t alignment_ |
40 | > |
41 | struct aligned_storage_imp |
42 | { |
43 | union data_t |
44 | { |
45 | char buf[size_]; |
46 | |
47 | typename ::boost::type_with_alignment<alignment_>::type align_; |
48 | } data_; |
49 | void* address() const { return const_cast<aligned_storage_imp*>(this); } |
50 | }; |
51 | template <std::size_t size> |
52 | struct aligned_storage_imp<size, std::size_t(-1)> |
53 | { |
54 | union data_t |
55 | { |
56 | char buf[size]; |
57 | ::boost::detail::max_align align_; |
58 | } data_; |
59 | void* address() const { return const_cast<aligned_storage_imp*>(this); } |
60 | }; |
61 | |
62 | template< std::size_t alignment_ > |
63 | struct aligned_storage_imp<0u,alignment_> |
64 | { |
65 | /* intentionally empty */ |
66 | void* address() const { return 0; } |
67 | }; |
68 | |
69 | }} // namespace detail::aligned_storage |
70 | |
71 | template < |
72 | std::size_t size_ |
73 | , std::size_t alignment_ = std::size_t(-1) |
74 | > |
75 | class aligned_storage : |
76 | #ifndef BOOST_BORLANDC |
77 | private |
78 | #else |
79 | public |
80 | #endif |
81 | ::boost::detail::aligned_storage::aligned_storage_imp<size_, alignment_> |
82 | { |
83 | |
84 | public: // constants |
85 | |
86 | typedef ::boost::detail::aligned_storage::aligned_storage_imp<size_, alignment_> type; |
87 | |
88 | BOOST_STATIC_CONSTANT( |
89 | std::size_t |
90 | , size = size_ |
91 | ); |
92 | BOOST_STATIC_CONSTANT( |
93 | std::size_t |
94 | , alignment = ( |
95 | alignment_ == std::size_t(-1) |
96 | ? ::boost::detail::aligned_storage::alignment_of_max_align |
97 | : alignment_ |
98 | ) |
99 | ); |
100 | |
101 | private: // noncopyable |
102 | |
103 | aligned_storage(const aligned_storage&); |
104 | aligned_storage& operator=(const aligned_storage&); |
105 | |
106 | public: // structors |
107 | |
108 | aligned_storage() |
109 | { |
110 | } |
111 | |
112 | ~aligned_storage() |
113 | { |
114 | } |
115 | |
116 | public: // accessors |
117 | |
118 | void* address() |
119 | { |
120 | return static_cast<type*>(this)->address(); |
121 | } |
122 | |
123 | const void* address() const |
124 | { |
125 | return static_cast<const type*>(this)->address(); |
126 | } |
127 | }; |
128 | |
129 | // |
130 | // Make sure that is_pod recognises aligned_storage<>::type |
131 | // as a POD (Note that aligned_storage<> itself is not a POD): |
132 | // |
133 | template <std::size_t size_, std::size_t alignment_> |
134 | struct is_pod< ::boost::detail::aligned_storage::aligned_storage_imp<size_, alignment_> > : public true_type{}; |
135 | |
136 | } // namespace boost |
137 | |
138 | #endif // BOOST_ALIGNED_STORAGE_HPP |
139 | |