source: NonGTP/Boost/boost/aligned_storage.hpp @ 857

Revision 857, 4.0 KB checked in by igarcia, 19 years ago (diff)
Line 
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 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_;
57};
58
59}} // namespace detail::aligned_storage
60
61template <
62      std::size_t size_
63    , std::size_t alignment_ = std::size_t(-1)
64>
65class aligned_storage
66{
67private: // representation
68
69   detail::aligned_storage::aligned_storage_imp<size_, alignment_> data_;
70
71public: // constants
72
73    typedef detail::aligned_storage::aligned_storage_imp<size_, alignment_> type;
74
75    BOOST_STATIC_CONSTANT(
76          std::size_t
77        , size = size_
78        );
79    BOOST_STATIC_CONSTANT(
80          std::size_t
81        , alignment = (
82              alignment_ == std::size_t(-1)
83            ? ::boost::detail::aligned_storage::alignment_of_max_align
84            : alignment_
85            )
86        );
87
88#if defined(__GNUC__) &&\
89    (__GNUC__ >  3) ||\
90    (__GNUC__ == 3 && (__GNUC_MINOR__ >  2 ||\
91                      (__GNUC_MINOR__ == 2 && __GNUC_PATCHLEVEL__ >=3)))
92
93private: // noncopyable
94
95    aligned_storage(const aligned_storage&);
96    aligned_storage& operator=(const aligned_storage&);
97
98#else // gcc less than 3.2.3
99
100public: // _should_ be noncopyable, but GCC compiler emits error
101
102    aligned_storage(const aligned_storage&);
103    aligned_storage& operator=(const aligned_storage&);
104
105#endif // gcc < 3.2.3 workaround
106
107public: // structors
108
109    aligned_storage()
110    {
111    }
112
113    ~aligned_storage()
114    {
115    }
116
117public: // accessors
118
119    void* address()
120    {
121        return this;
122    }
123
124#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
125
126    const void* address() const
127    {
128        return this;
129    }
130
131#else // MSVC6
132
133    const void* address() const;
134
135#endif // MSVC6 workaround
136
137};
138
139#if BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
140
141// MSVC6 seems not to like inline functions with const void* returns, so we
142// declare the following here:
143
144template <std::size_t S, std::size_t A>
145const void* aligned_storage<S,A>::address() const
146{
147    return const_cast< aligned_storage<S,A>* >(this)->address();
148}
149
150#endif // MSVC6 workaround
151
152#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
153//
154// Make sure that is_pod recognises aligned_storage<>::type
155// as a POD (Note that aligned_storage<> itself is not a POD):
156//
157template <std::size_t size_, std::size_t alignment_>
158struct is_pod<boost::detail::aligned_storage::aligned_storage_imp<size_,alignment_> >
159   BOOST_TT_AUX_BOOL_C_BASE(true)
160{
161    BOOST_TT_AUX_BOOL_TRAIT_VALUE_DECL(true)
162};
163#endif
164
165
166} // namespace boost
167
168#include "boost/type_traits/detail/bool_trait_undef.hpp"
169
170#endif // BOOST_ALIGNED_STORAGE_HPP
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