libstdc++-v3/include/ext/aligned_buffer.h

   1 // Aligned memory buffer -*- C++ -*-
   2
   3 // Copyright (C) 2013-2014 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 */