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
29 namespace boost {
30
31 namespace detail { namespace aligned_storage {
32
33 BOOST_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 //
41 template <
42 std::size_t size_
43 , std::size_t alignment_
44 >
45 struct aligned_storage_imp
46 {
47 union data_t
48 {
49 char buf[size_];
50
51 typename mpl::eval_if_c<
52 alignment_ == std::size_t(-1)
53 , mpl::identity<detail::max_align>
54 , type_with_alignment<alignment_>
55 >::type align_;
56 } data_;
addressboost::detail::aligned_storage::aligned_storage_imp57 void* address() const { return const_cast<aligned_storage_imp*>(this); }
58 };
59
60 template< std::size_t alignment_ >
61 struct aligned_storage_imp<0u,alignment_>
62 {
63 /* intentionally empty */
addressboost::detail::aligned_storage::aligned_storage_imp64 void* address() const { return 0; }
65 };
66
67 }} // namespace detail::aligned_storage
68
69 template <
70 std::size_t size_
71 , std::size_t alignment_ = std::size_t(-1)
72 >
73 class aligned_storage :
74 #ifndef __BORLANDC__
75 private
76 #else
77 public
78 #endif
79 detail::aligned_storage::aligned_storage_imp<size_, alignment_>
80 {
81
82 public: // constants
83
84 typedef 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
99 #if defined(__GNUC__) &&\
100 (__GNUC__ > 3) ||\
101 (__GNUC__ == 3 && (__GNUC_MINOR__ > 2 ||\
102 (__GNUC_MINOR__ == 2 && __GNUC_PATCHLEVEL__ >=3)))
103
104 private: // noncopyable
105
106 aligned_storage(const aligned_storage&);
107 aligned_storage& operator=(const aligned_storage&);
108
109 #else // gcc less than 3.2.3
110
111 public: // _should_ be noncopyable, but GCC compiler emits error
112
113 aligned_storage(const aligned_storage&);
114 aligned_storage& operator=(const aligned_storage&);
115
116 #endif // gcc < 3.2.3 workaround
117
118 public: // structors
119
aligned_storage()120 aligned_storage()
121 {
122 }
123
~aligned_storage()124 ~aligned_storage()
125 {
126 }
127
128 public: // accessors
129
address()130 void* address()
131 {
132 return static_cast<type*>(this)->address();
133 }
134
135 #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
136
address() const137 const void* address() const
138 {
139 return static_cast<const type*>(this)->address();
140 }
141
142 #else // MSVC6
143
144 const void* address() const;
145
146 #endif // MSVC6 workaround
147
148 };
149
150 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
151
152 // MSVC6 seems not to like inline functions with const void* returns, so we
153 // declare the following here:
154
155 template <std::size_t S, std::size_t A>
address() const156 const void* aligned_storage<S,A>::address() const
157 {
158 return const_cast< aligned_storage<S,A>* >(this)->address();
159 }
160
161 #endif // MSVC6 workaround
162
163 #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
164 //
165 // Make sure that is_pod recognises aligned_storage<>::type
166 // as a POD (Note that aligned_storage<> itself is not a POD):
167 //
168 template <std::size_t size_, std::size_t alignment_>
169 struct is_pod<boost::detail::aligned_storage::aligned_storage_imp<size_,alignment_> >
BOOST_TT_AUX_BOOL_C_BASE(true)170 BOOST_TT_AUX_BOOL_C_BASE(true)
171 {
172 BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(true)
173 };
174 #endif
175
176
177 } // namespace boost
178
179 #include "boost/type_traits/detail/bool_trait_undef.hpp"
180
181 #endif // BOOST_ALIGNED_STORAGE_HPP
182