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/*
* 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) 2014 Andrey Semashev
*/
/*!
* \file atomic/detail/ops_extending_cas_based.hpp
*
* This header contains a boilerplate of the \c operations template implementation that requires sign/zero extension in arithmetic operations.
*/
#ifndef BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
#include <cstddef>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/storage_type.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
template< typename Base, std::size_t Size, bool Signed >
struct extending_cas_based_operations :
public Base
{
typedef typename Base::storage_type storage_type;
typedef typename make_storage_type< Size, Signed >::type emulated_storage_type;
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
storage_type old_val;
atomics::detail::non_atomic_load(storage, old_val);
emulated_storage_type new_val;
do
{
new_val = static_cast< emulated_storage_type >(old_val) + static_cast< emulated_storage_type >(v);
}
while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
return old_val;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
{
storage_type old_val;
atomics::detail::non_atomic_load(storage, old_val);
emulated_storage_type new_val;
do
{
new_val = static_cast< emulated_storage_type >(old_val) - static_cast< emulated_storage_type >(v);
}
while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
return old_val;
}
};
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
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