boost/atomic/detail/ops_emulated.hpp
/*
* 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_emulated.hpp
*
* This header contains lockpool-based implementation of the \c operations template.
*/
#ifndef BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_
#include <cstddef>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/storage_type.hpp>
#include <boost/atomic/detail/operations_fwd.hpp>
#include <boost/atomic/detail/lockpool.hpp>
#include <boost/atomic/capabilities.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
template< typename T >
struct emulated_operations
{
typedef T storage_type;
static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = false;
static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
lockpool::scoped_lock lock(&storage);
const_cast< storage_type& >(storage) = v;
}
static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order) BOOST_NOEXCEPT
{
lockpool::scoped_lock lock(&storage);
return const_cast< storage_type const& >(storage);
}
static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s += v;
return old_val;
}
static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s -= v;
return old_val;
}
static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s = v;
return old_val;
}
static BOOST_FORCEINLINE bool compare_exchange_strong(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
const bool res = old_val == expected;
if (res)
s = desired;
expected = old_val;
return res;
}
static BOOST_FORCEINLINE bool compare_exchange_weak(
storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
{
// Note: This function is the exact copy of compare_exchange_strong. The reason we're not just forwarding the call
// is that MSVC-12 ICEs in this case.
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
const bool res = old_val == expected;
if (res)
s = desired;
expected = old_val;
return res;
}
static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s &= v;
return old_val;
}
static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s |= v;
return old_val;
}
static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
{
storage_type& s = const_cast< storage_type& >(storage);
lockpool::scoped_lock lock(&storage);
storage_type old_val = s;
s ^= v;
return old_val;
}
static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
return !!exchange(storage, (storage_type)1, order);
}
static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
{
store(storage, (storage_type)0, order);
}
};
template< std::size_t Size, bool Signed >
struct operations :
public emulated_operations< typename make_storage_type< Size, Signed >::type >
{
typedef typename make_storage_type< Size, Signed >::aligned aligned_storage_type;
static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = Size;
static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
};
} // namespace detail
} // namespace atomics
} // namespace boost
#endif // BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_