ceph/src/boost/libs/atomic/test/aligned_object.hpp

   1 //  Copyright (c) 2020 Andrey Semashev
   2 //
   3 //  Distributed under the Boost Software License, Version 1.0.
   4 //  See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_ATOMIC_TESTS_ALIGNED_OBJECT_HPP_INCLUDED_
   8 #define BOOST_ATOMIC_TESTS_ALIGNED_OBJECT_HPP_INCLUDED_
   9
  10 #include <cstddef>
  11 #include <new>
  12 #include <boost/config.hpp>
  13 #include <boost/cstdint.hpp>
  14
  15 //! A wrapper that creates an object that has at least the specified alignment
  16 template< typename T, std::size_t Alignment >
  17 class aligned_object
  18 {
  19 private:
  20     T* m_p;
  21     unsigned char m_storage[Alignment + sizeof(T)];
  22
  23 public:
  24     aligned_object()
  25     {
  26         m_p = new (get_aligned_storage()) T;
  27     }
  28
  29     explicit aligned_object(T const& value)
  30     {
  31         m_p = new (get_aligned_storage()) T(value);
  32     }
  33
  34     ~aligned_object() BOOST_NOEXCEPT
  35     {
  36         m_p->~T();
  37     }
  38
  39     T& get() const BOOST_NOEXCEPT
  40     {
  41         return *m_p;
  42     }
  43
  44     BOOST_DELETED_FUNCTION(aligned_object(aligned_object const&))
  45     BOOST_DELETED_FUNCTION(aligned_object& operator= (aligned_object const&))
  46
  47 private:
  48     unsigned char* get_aligned_storage()
  49     {
  50 #if defined(BOOST_HAS_INTPTR_T)
  51         typedef boost::uintptr_t uintptr_type;
  52 #else
  53         typedef std::size_t uintptr_type;
  54 #endif
  55         uintptr_type p = (uintptr_type)(unsigned char*)m_storage;
  56         p = (p + (uintptr_type)(Alignment - 1u)) & ~(uintptr_type)(Alignment - 1u);
  57         return (unsigned char*)p;
  58     }
  59 };
  60
  61 #endif // BOOST_ATOMIC_TESTS_ALIGNED_OBJECT_HPP_INCLUDED_