#ifndef BOOST_INTERPROCESS_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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#define BOOST_INTERPROCESS_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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#ifndef BOOST_CONFIG_HPP
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# include <boost/config.hpp>
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#endif
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#
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#if defined(BOOST_HAS_PRAGMA_ONCE)
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# pragma once
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#endif
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// Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
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// Copyright 2004-2005 Peter Dimov
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// Copyright 2007-2012 Ion Gaztanaga
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// 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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//
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// Lock-free algorithm by Alexander Terekhov
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//
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// Thanks to Ben Hitchings for the #weak + (#shared != 0)
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// formulation
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//
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#include <boost/interprocess/detail/config_begin.hpp>
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#include <boost/interprocess/detail/workaround.hpp>
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#include <boost/interprocess/detail/atomic.hpp>
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#include <typeinfo>
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namespace boost {
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namespace interprocess {
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namespace ipcdetail {
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class sp_counted_base
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{
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private:
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sp_counted_base( sp_counted_base const & );
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sp_counted_base & operator= ( sp_counted_base const & );
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boost::uint32_t use_count_; // #shared
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boost::uint32_t weak_count_; // #weak + (#shared != 0)
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public:
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sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
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{}
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~sp_counted_base() // nothrow
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{}
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void add_ref_copy()
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{
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ipcdetail::atomic_inc32( &use_count_ );
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}
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bool add_ref_lock() // true on success
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{
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for( ;; )
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{
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boost::uint32_t tmp = static_cast< boost::uint32_t const volatile& >( use_count_ );
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if( tmp == 0 ) return false;
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if( ipcdetail::atomic_cas32( &use_count_, tmp + 1, tmp ) == tmp )
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return true;
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}
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}
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bool ref_release() // nothrow
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{ return 1 == ipcdetail::atomic_dec32( &use_count_ ); }
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void weak_add_ref() // nothrow
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{ ipcdetail::atomic_inc32( &weak_count_ ); }
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bool weak_release() // nothrow
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{ return 1 == ipcdetail::atomic_dec32( &weak_count_ ); }
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long use_count() const // nothrow
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{ return (long)static_cast<boost::uint32_t const volatile &>( use_count_ ); }
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};
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} // namespace ipcdetail
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} // namespace interprocess
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} // namespace boost
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#include <boost/interprocess/detail/config_end.hpp>
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#endif // #ifndef BOOST_INTERPROCESS_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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