libstdc++
aligned_buffer.h
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1 // Aligned memory buffer -*- C++ -*-
2 
3 // Copyright (C) 2013-2015 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file ext/aligned_buffer.h
26  * This file is a GNU extension to the Standard C++ Library.
27  */
28 
29 #ifndef _ALIGNED_BUFFER_H
30 #define _ALIGNED_BUFFER_H 1
31 
32 #pragma GCC system_header
33 
34 #if __cplusplus >= 201103L
35 # include <type_traits>
36 #else
37 # include <bits/c++0x_warning.h>
38 #endif
39 
40 namespace __gnu_cxx
41 {
42  template<typename _Tp>
43  struct __aligned_buffer
44  : std::aligned_storage<sizeof(_Tp), std::alignment_of<_Tp>::value>
45  {
46  typename
47  std::aligned_storage<sizeof(_Tp), std::alignment_of<_Tp>::value>::type
48  _M_storage;
49 
50  __aligned_buffer() = default;
51 
52  // Can be used to avoid value-initialization
53  __aligned_buffer(std::nullptr_t) { }
54 
55  void*
56  _M_addr() noexcept
57  {
58  return static_cast<void*>(&_M_storage);
59  }
60 
61  const void*
62  _M_addr() const noexcept
63  {
64  return static_cast<const void*>(&_M_storage);
65  }
66 
67  _Tp*
68  _M_ptr() noexcept
69  { return static_cast<_Tp*>(_M_addr()); }
70 
71  const _Tp*
72  _M_ptr() const noexcept
73  { return static_cast<const _Tp*>(_M_addr()); }
74  };
75 
76 } // namespace
77 
78 #endif /* _ALIGNED_BUFFER_H */
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