#ifndef BOOST_STATECHART_DETAIL_COUNTED_BASE_HPP_INCLUDED
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#define BOOST_STATECHART_DETAIL_COUNTED_BASE_HPP_INCLUDED
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//////////////////////////////////////////////////////////////////////////////
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// Copyright 2002-2006 Andreas Huber Doenni
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// Distributed under the Boost Software License, Version 1.0. (See accompany-
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// ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//////////////////////////////////////////////////////////////////////////////
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#include <boost/detail/atomic_count.hpp>
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#include <boost/config.hpp> // BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP
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namespace boost
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{
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namespace statechart
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{
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namespace detail
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{
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template< bool NeedsLocking >
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struct count_base
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{
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count_base() : count_( 0 ) {}
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mutable boost::detail::atomic_count count_;
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};
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template<>
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struct count_base< false >
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{
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count_base() : count_( 0 ) {}
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mutable long count_;
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};
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//////////////////////////////////////////////////////////////////////////////
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template< bool NeedsLocking = true >
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class counted_base : private count_base< NeedsLocking >
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{
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typedef count_base< NeedsLocking > base_type;
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public:
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//////////////////////////////////////////////////////////////////////////
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bool ref_counted() const
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{
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return base_type::count_ != 0;
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}
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long ref_count() const
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{
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return base_type::count_;
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}
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protected:
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//////////////////////////////////////////////////////////////////////////
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counted_base() {}
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~counted_base() {}
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// do nothing copy implementation is intentional (the number of
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// referencing pointers of the source and the destination is not changed
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// through the copy operation)
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counted_base( const counted_base & ) : base_type() {}
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counted_base & operator=( const counted_base & ) { return *this; }
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public:
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//////////////////////////////////////////////////////////////////////////
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// The following declarations should be private.
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// They are only public because many compilers lack template friends.
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//////////////////////////////////////////////////////////////////////////
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void add_ref() const
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{
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++base_type::count_;
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}
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bool release() const
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{
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BOOST_ASSERT( base_type::count_ > 0 );
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return --base_type::count_ == 0;
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}
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};
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} // namespace detail
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} // namespace statechart
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} // namespace boost
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#endif
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