/*
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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, 2020 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/core_operations_emulated.hpp
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*
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* This header contains lock pool-based implementation of the core atomic operations.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_CORE_OPERATIONS_EMULATED_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_CORE_OPERATIONS_EMULATED_HPP_INCLUDED_
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#include <cstddef>
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#include <boost/static_assert.hpp>
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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/storage_traits.hpp>
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#include <boost/atomic/detail/core_operations_emulated_fwd.hpp>
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#include <boost/atomic/detail/lock_pool.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< std::size_t Size, std::size_t Alignment, bool = Alignment >= storage_traits< Size >::native_alignment >
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struct core_operations_emulated_base
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{
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typedef typename storage_traits< Size >::type storage_type;
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};
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template< std::size_t Size, std::size_t Alignment >
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struct core_operations_emulated_base< Size, Alignment, false >
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{
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typedef buffer_storage< Size, Alignment > storage_type;
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};
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//! Emulated implementation of core atomic operations
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template< std::size_t Size, std::size_t Alignment, bool Signed, bool Interprocess >
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struct core_operations_emulated :
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public core_operations_emulated_base< Size, Alignment >
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{
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typedef core_operations_emulated_base< Size, Alignment > base_type;
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// Define storage_type to have alignment not greater than Alignment. This will allow operations to work with value_types
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// that possibly have weaker alignment requirements than storage_traits< Size >::type would. This is important for atomic_ref<>.
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// atomic<> will allow higher alignment requirement than its value_type.
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// Note that storage_type should be an integral type, if possible, so that arithmetic and bitwise operations are possible.
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typedef typename base_type::storage_type storage_type;
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static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = Size;
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static BOOST_CONSTEXPR_OR_CONST std::size_t storage_alignment = Alignment >= storage_traits< Size >::alignment ? storage_traits< Size >::alignment : Alignment;
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static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
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static BOOST_CONSTEXPR_OR_CONST bool is_interprocess = Interprocess;
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static BOOST_CONSTEXPR_OR_CONST bool full_cas_based = false;
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static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = false;
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typedef lock_pool::scoped_lock< storage_alignment > scoped_lock;
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static void store(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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scoped_lock lock(&storage);
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const_cast< storage_type& >(storage) = v;
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}
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static storage_type load(storage_type const volatile& storage, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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scoped_lock lock(&storage);
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return const_cast< storage_type const& >(storage);
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}
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static storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s += v;
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return old_val;
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}
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static storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s -= v;
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return old_val;
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}
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static storage_type exchange(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s = v;
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return old_val;
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}
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static bool compare_exchange_strong(
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storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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const bool res = old_val == expected;
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if (res)
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s = desired;
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expected = old_val;
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return res;
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}
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static bool compare_exchange_weak(
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storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
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{
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// Note: This function is the exact copy of compare_exchange_strong. The reason we're not just forwarding the call
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// is that MSVC-12 ICEs in this case.
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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const bool res = old_val == expected;
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if (res)
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s = desired;
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expected = old_val;
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return res;
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}
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static storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s &= v;
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return old_val;
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}
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static storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s |= v;
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return old_val;
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}
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static storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type& s = const_cast< storage_type& >(storage);
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scoped_lock lock(&storage);
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storage_type old_val = s;
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s ^= v;
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return old_val;
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}
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static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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return !!exchange(storage, (storage_type)1, order);
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}
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static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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store(storage, (storage_type)0, order);
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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_CORE_OPERATIONS_EMULATED_HPP_INCLUDED_
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