ceph/src/boost/libs/atomic/include/boost/atomic/detail/bitwise_cast.hpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2009 Helge Bahmann
   7  * Copyright (c) 2012 Tim Blechmann
   8  * Copyright (c) 2013 - 2014 Andrey Semashev
   9  */
  10 /*!
  11  * \file   atomic/detail/bitwise_cast.hpp
  12  *
  13  * This header defines \c bitwise_cast used to convert between storage and value types
  14  */
  15
  16 #ifndef BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
  17 #define BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
  18
  19 #include <boost/atomic/detail/config.hpp>
  20 #if !defined(BOOST_ATOMIC_DETAIL_HAS_BUILTIN_MEMCPY)
  21 #include <cstring>
  22 #endif
  23
  24 #ifdef BOOST_HAS_PRAGMA_ONCE
  25 #pragma once
  26 #endif
  27
  28 namespace boost {
  29 namespace atomics {
  30 namespace detail {
  31
  32 template< typename To, typename From >
  33 BOOST_FORCEINLINE To bitwise_cast(From const& from) BOOST_NOEXCEPT
  34 {
  35     struct
  36     {
  37         To to;
  38     }
  39     value = {};
  40     BOOST_ATOMIC_DETAIL_MEMCPY
  41     (
  42         &reinterpret_cast< char& >(value.to),
  43         &reinterpret_cast< const char& >(from),
  44         (sizeof(From) < sizeof(To) ? sizeof(From) : sizeof(To))
  45     );
  46     return value.to;
  47 }
  48
  49 } // namespace detail
  50 } // namespace atomics
  51 } // namespace boost
  52
  53 #endif // BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_