#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED // // detail/sp_counted_base_aix.hpp // based on: detail/sp_counted_base_w32.hpp // // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. // Copyright 2004-2005 Peter Dimov // Copyright 2006 Michael van der Westhuizen // // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) // // // Lock-free algorithm by Alexander Terekhov // // Thanks to Ben Hitchings for the #weak + (#shared != 0) // formulation // #include <boost/detail/sp_typeinfo.hpp> #include <builtins.h> #include <sys/atomic_op.h> namespace boost { namespace detail { inline void atomic_increment( int32_t* pw ) { // ++*pw; fetch_and_add( pw, 1 ); } inline int32_t atomic_decrement( int32_t * pw ) { // return --*pw; int32_t originalValue; __lwsync(); originalValue = fetch_and_add( pw, -1 ); __isync(); return (originalValue - 1); } inline int32_t atomic_conditional_increment( int32_t * pw ) { // if( *pw != 0 ) ++*pw; // return *pw; int32_t tmp = fetch_and_add( pw, 0 ); for( ;; ) { if( tmp == 0 ) return 0; if( compare_and_swap( pw, &tmp, tmp + 1 ) ) return (tmp + 1); } } class sp_counted_base { private: sp_counted_base( sp_counted_base const & ); sp_counted_base & operator= ( sp_counted_base const & ); int32_t use_count_; // #shared int32_t weak_count_; // #weak + (#shared != 0) public: sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) { } virtual ~sp_counted_base() // nothrow { } // dispose() is called when use_count_ drops to zero, to release // the resources managed by *this. virtual void dispose() = 0; // nothrow // destroy() is called when weak_count_ drops to zero. virtual void destroy() // nothrow { delete this; } virtual void * get_deleter( sp_typeinfo const & ti ) = 0; void add_ref_copy() { atomic_increment( &use_count_ ); } bool add_ref_lock() // true on success { return atomic_conditional_increment( &use_count_ ) != 0; } void release() // nothrow { if( atomic_decrement( &use_count_ ) == 0 ) { dispose(); weak_release(); } } void weak_add_ref() // nothrow { atomic_increment( &weak_count_ ); } void weak_release() // nothrow { if( atomic_decrement( &weak_count_ ) == 0 ) { destroy(); } } long use_count() const // nothrow { return fetch_and_add( const_cast<int32_t*>(&use_count_), 0 ); } }; } // namespace detail } // namespace boost #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED