/*
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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) 2020 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/wait_ops_emulated.hpp
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*
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* This header contains emulated (lock-based) implementation of the waiting and notifying atomic operations.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_EMULATED_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_WAIT_OPS_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/lock_pool.hpp>
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#include <boost/atomic/detail/wait_operations_fwd.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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//! Emulated implementation of waiting and notifying operations
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template< typename Base >
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struct wait_operations_emulated :
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public Base
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{
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typedef Base base_type;
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typedef typename base_type::storage_type storage_type;
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typedef lock_pool::scoped_lock< base_type::storage_alignment, true > scoped_lock;
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typedef lock_pool::scoped_wait_state< base_type::storage_alignment > scoped_wait_state;
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static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = false;
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static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT
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{
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return false;
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}
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static
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#if defined(BOOST_MSVC) && BOOST_MSVC < 1500
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// In some cases, when this function is inlined, MSVC-8 (VS2005) x64 generates broken code that returns a bogus value from this function.
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BOOST_NOINLINE
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#endif
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storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!base_type::is_interprocess, "Boost.Atomic: operation invoked on a non-lock-free inter-process atomic object");
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storage_type const& s = const_cast< storage_type const& >(storage);
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scoped_wait_state wait_state(&storage);
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storage_type new_val = s;
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while (new_val == old_val)
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{
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wait_state.wait();
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new_val = s;
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}
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return new_val;
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}
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static void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!base_type::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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lock_pool::notify_one(lock.get_lock_state(), &storage);
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}
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static void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
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{
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BOOST_STATIC_ASSERT_MSG(!base_type::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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lock_pool::notify_all(lock.get_lock_state(), &storage);
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}
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};
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template< typename Base, std::size_t Size, bool Interprocess >
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struct wait_operations< Base, Size, false, Interprocess > :
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public wait_operations_emulated< Base >
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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_WAIT_OPS_EMULATED_HPP_INCLUDED_
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