51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
/*
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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) 2014 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/cas_based_exchange.hpp
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*
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* This header contains CAS-based implementation of exchange operation.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_CAS_BASED_EXCHANGE_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_CAS_BASED_EXCHANGE_HPP_INCLUDED_
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#include <boost/memory_order.hpp>
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#include <boost/atomic/detail/config.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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namespace boost {
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namespace atomics {
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namespace detail {
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template< typename Base >
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struct cas_based_exchange :
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public Base
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{
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typedef typename Base::storage_type storage_type;
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static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
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{
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storage_type old_val;
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atomics::detail::non_atomic_load(storage, old_val);
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while (!Base::compare_exchange_weak(storage, old_val, v, order, memory_order_relaxed)) {}
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return old_val;
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}
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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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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_CAS_BASED_EXCHANGE_HPP_INCLUDED_
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