WSJT-X/boost/boost/atomic/detail/bitwise_cast.hpp

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2.0 KiB
C++

/*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* Copyright (c) 2009 Helge Bahmann
* Copyright (c) 2012 Tim Blechmann
* Copyright (c) 2013 - 2018 Andrey Semashev
*/
/*!
* \file atomic/detail/bitwise_cast.hpp
*
* This header defines \c bitwise_cast used to convert between storage and value types
*/
#ifndef BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
#include <cstddef>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/addressof.hpp>
#include <boost/atomic/detail/string_ops.hpp>
#include <boost/atomic/detail/type_traits/integral_constant.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
template< std::size_t FromSize, typename To >
BOOST_FORCEINLINE void clear_padding(To& to, atomics::detail::true_type) BOOST_NOEXCEPT
{
BOOST_ATOMIC_DETAIL_MEMSET(reinterpret_cast< unsigned char* >(atomics::detail::addressof(to)) + FromSize, 0, sizeof(To) - FromSize);
}
template< std::size_t FromSize, typename To >
BOOST_FORCEINLINE void clear_padding(To&, atomics::detail::false_type) BOOST_NOEXCEPT
{
}
template< typename To, std::size_t FromSize, typename From >
BOOST_FORCEINLINE To bitwise_cast(From const& from) BOOST_NOEXCEPT
{
To to;
BOOST_ATOMIC_DETAIL_MEMCPY
(
atomics::detail::addressof(to),
atomics::detail::addressof(from),
(FromSize < sizeof(To) ? FromSize : sizeof(To))
);
atomics::detail::clear_padding< FromSize >(to, atomics::detail::integral_constant< bool, FromSize < sizeof(To) >());
return to;
}
template< typename To, typename From >
BOOST_FORCEINLINE To bitwise_cast(From const& from) BOOST_NOEXCEPT
{
return atomics::detail::bitwise_cast< To, sizeof(From) >(from);
}
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_