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_ALIGNED_STORAGE_HPP
14#define BOOST_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
24#include "boost/mpl/eval_if.hpp"
25#include "boost/mpl/identity.hpp"
26
27#include "boost/type_traits/detail/bool_trait_def.hpp"
28
29namespace boost {
30
31namespace detail { namespace aligned_storage {
32
33BOOST_STATIC_CONSTANT(
34 std::size_t
35 , alignment_of_max_align = ::boost::alignment_of<max_align>::value
36 );
37
38//
39// To be TR1 conforming this must be a POD type:
40//
41template <
42 std::size_t size_
43 , std::size_t alignment_
44>
45struct aligned_storage_imp
46{
47 union data_t
48 {
49 char buf[size_];
50
51 typename ::boost::mpl::eval_if_c<
52 alignment_ == std::size_t(-1)
53 , ::boost::mpl::identity< ::boost::detail::max_align >
54 , ::boost::type_with_alignment<alignment_>
55 >::type align_;
56 } data_;
57 void* address() const { return const_cast<aligned_storage_imp*>(this); }
58};
59
60template< std::size_t alignment_ >
61struct aligned_storage_imp<0u,alignment_>
62{
63 /* intentionally empty */
64 void* address() const { return 0; }
65};
66
67}} // namespace detail::aligned_storage
68
69template <
70 std::size_t size_
71 , std::size_t alignment_ = std::size_t(-1)
72>
73class aligned_storage :
74#ifndef __BORLANDC__
75 private
76#else
77 public
78#endif
79 ::boost::detail::aligned_storage::aligned_storage_imp<size_, alignment_>
80{
81
82public: // constants
83
84 typedef ::boost::detail::aligned_storage::aligned_storage_imp<size_, alignment_> type;
85
86 BOOST_STATIC_CONSTANT(
87 std::size_t
88 , size = size_
89 );
90 BOOST_STATIC_CONSTANT(
91 std::size_t
92 , alignment = (
93 alignment_ == std::size_t(-1)
94 ? ::boost::detail::aligned_storage::alignment_of_max_align
95 : alignment_
96 )
97 );
98
99private: // noncopyable
100
101 aligned_storage(const aligned_storage&);
102 aligned_storage& operator=(const aligned_storage&);
103
104public: // structors
105
106 aligned_storage()
107 {
108 }
109
110 ~aligned_storage()
111 {
112 }
113
114public: // accessors
115
116 void* address()
117 {
118 return static_cast<type*>(this)->address();
119 }
120
121 const void* address() const
122 {
123 return static_cast<const type*>(this)->address();
124 }
125};
126
127//
128// Make sure that is_pod recognises aligned_storage<>::type
129// as a POD (Note that aligned_storage<> itself is not a POD):
130//
131template <std::size_t size_, std::size_t alignment_>
132struct is_pod< ::boost::detail::aligned_storage::aligned_storage_imp<size_,alignment_> >
133 BOOST_TT_AUX_BOOL_C_BASE(true)
134{
135 BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(true)
136};
137
138
139} // namespace boost
140
141#include "boost/type_traits/detail/bool_trait_undef.hpp"
142
143#endif // BOOST_ALIGNED_STORAGE_HPP
144