Chris@102: /*
Chris@102:  * Distributed under the Boost Software License, Version 1.0.
Chris@102:  * (See accompanying file LICENSE_1_0.txt or copy at
Chris@102:  * http://www.boost.org/LICENSE_1_0.txt)
Chris@102:  *
Chris@102:  * Copyright (c) 2009 Helge Bahmann
Chris@102:  * Copyright (c) 2012 Tim Blechmann
Chris@102:  * Copyright (c) 2013 - 2014 Andrey Semashev
Chris@102:  */
Chris@102: /*!
Chris@102:  * \file   atomic/detail/casts.hpp
Chris@102:  *
Chris@102:  * This header defines \c union_cast and \c memcpy_cast used to convert between storage and value types
Chris@102:  */
Chris@102: 
Chris@102: #ifndef BOOST_ATOMIC_DETAIL_CASTS_HPP_INCLUDED_
Chris@102: #define BOOST_ATOMIC_DETAIL_CASTS_HPP_INCLUDED_
Chris@102: 
Chris@102: #include <cstring>
Chris@102: #include <boost/atomic/detail/config.hpp>
Chris@102: 
Chris@102: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: namespace boost {
Chris@102: namespace atomics {
Chris@102: namespace detail {
Chris@102: 
Chris@102: template< typename To, typename From >
Chris@102: BOOST_FORCEINLINE To union_cast(From const& from) BOOST_NOEXCEPT
Chris@102: {
Chris@102:     union
Chris@102:     {
Chris@102:         To as_to;
Chris@102:         From as_from;
Chris@102:     }
Chris@102:     caster = {};
Chris@102:     caster.as_from = from;
Chris@102:     return caster.as_to;
Chris@102: }
Chris@102: 
Chris@102: template< typename To, typename From >
Chris@102: BOOST_FORCEINLINE To memcpy_cast(From const& from) BOOST_NOEXCEPT
Chris@102: {
Chris@102:     struct
Chris@102:     {
Chris@102:         To to;
Chris@102:     }
Chris@102:     value = {};
Chris@102:     std::memcpy
Chris@102:     (
Chris@102:         &reinterpret_cast< char& >(value.to),
Chris@102:         &reinterpret_cast< const char& >(from),
Chris@102:         (sizeof(From) < sizeof(To) ? sizeof(From) : sizeof(To))
Chris@102:     );
Chris@102:     return value.to;
Chris@102: }
Chris@102: 
Chris@102: } // namespace detail
Chris@102: } // namespace atomics
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #endif // BOOST_ATOMIC_DETAIL_CASTS_HPP_INCLUDED_