/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2009 Helge Bahmann
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* Copyright (c) 2012 Tim Blechmann
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* Copyright (c) 2013 - 2018, 2020 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/bitwise_cast.hpp
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*
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* This header defines \c bitwise_cast used to convert between storage and value types
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*/
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#ifndef BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
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#include <cstddef>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/addressof.hpp>
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#include <boost/atomic/detail/string_ops.hpp>
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#include <boost/atomic/detail/type_traits/integral_constant.hpp>
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#include <boost/atomic/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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#if defined(BOOST_GCC) && BOOST_GCC >= 80000
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#pragma GCC diagnostic push
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// copying an object of non-trivial type X from an array of Y. This is benign because we use memcpy to copy trivially copyable objects.
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#pragma GCC diagnostic ignored "-Wclass-memaccess"
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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template< std::size_t FromSize, typename To >
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BOOST_FORCEINLINE void clear_tail_padding_bits(To& to, atomics::detail::true_type) BOOST_NOEXCEPT
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{
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BOOST_ATOMIC_DETAIL_MEMSET(reinterpret_cast< unsigned char* >(atomics::detail::addressof(to)) + FromSize, 0, sizeof(To) - FromSize);
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}
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template< std::size_t FromSize, typename To >
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BOOST_FORCEINLINE void clear_tail_padding_bits(To&, atomics::detail::false_type) BOOST_NOEXCEPT
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{
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}
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template< std::size_t FromSize, typename To >
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BOOST_FORCEINLINE void clear_tail_padding_bits(To& to) BOOST_NOEXCEPT
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{
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atomics::detail::clear_tail_padding_bits< FromSize >(to, atomics::detail::integral_constant< bool, FromSize < sizeof(To) >());
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}
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template< typename To, std::size_t FromSize, typename From >
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BOOST_FORCEINLINE To bitwise_cast(From const& from) BOOST_NOEXCEPT
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{
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To to;
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BOOST_ATOMIC_DETAIL_MEMCPY
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(
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atomics::detail::addressof(to),
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atomics::detail::addressof(from),
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(FromSize < sizeof(To) ? FromSize : sizeof(To))
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);
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atomics::detail::clear_tail_padding_bits< FromSize >(to);
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return to;
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}
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template< typename To, typename From >
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BOOST_FORCEINLINE To bitwise_cast(From const& from) BOOST_NOEXCEPT
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{
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return atomics::detail::bitwise_cast< To, sizeof(From) >(from);
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}
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#if defined(BOOST_GCC) && BOOST_GCC >= 80000
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#pragma GCC diagnostic pop
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#endif
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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_BITWISE_CAST_HPP_INCLUDED_
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