143 lines
2.9 KiB
C++
143 lines
2.9 KiB
C++
#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED
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#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED
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//
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// detail/sp_counted_base_aix.hpp
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// based on: detail/sp_counted_base_w32.hpp
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//
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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 2006 Michael van der Westhuizen
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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/detail/sp_typeinfo.hpp>
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#include <builtins.h>
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#include <sys/atomic_op.h>
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namespace boost
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{
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namespace detail
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{
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inline void atomic_increment( int32_t* pw )
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{
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// ++*pw;
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fetch_and_add( pw, 1 );
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}
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inline int32_t atomic_decrement( int32_t * pw )
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{
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// return --*pw;
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int32_t originalValue;
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__lwsync();
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originalValue = fetch_and_add( pw, -1 );
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__isync();
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return (originalValue - 1);
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}
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inline int32_t atomic_conditional_increment( int32_t * pw )
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{
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// if( *pw != 0 ) ++*pw;
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// return *pw;
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int32_t tmp = fetch_and_add( pw, 0 );
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for( ;; )
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{
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if( tmp == 0 ) return 0;
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if( compare_and_swap( pw, &tmp, tmp + 1 ) ) return (tmp + 1);
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}
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}
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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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int32_t use_count_; // #shared
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int32_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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}
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virtual ~sp_counted_base() // nothrow
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{
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}
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// dispose() is called when use_count_ drops to zero, to release
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// the resources managed by *this.
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virtual void dispose() = 0; // nothrow
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// destroy() is called when weak_count_ drops to zero.
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virtual void destroy() // nothrow
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{
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delete this;
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}
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virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
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void add_ref_copy()
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{
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atomic_increment( &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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return atomic_conditional_increment( &use_count_ ) != 0;
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}
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void release() // nothrow
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{
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if( atomic_decrement( &use_count_ ) == 0 )
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{
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dispose();
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weak_release();
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}
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}
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void weak_add_ref() // nothrow
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{
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atomic_increment( &weak_count_ );
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}
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void weak_release() // nothrow
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{
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if( atomic_decrement( &weak_count_ ) == 0 )
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{
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destroy();
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}
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}
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long use_count() const // nothrow
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{
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return fetch_and_add( const_cast<int32_t*>(&use_count_), 0 );
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}
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};
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} // namespace detail
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} // namespace boost
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#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED
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