1 #ifndef BOOST_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED
2 #define BOOST_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED
4 // MS compatible compilers support #pragma once
6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
11 // detail/sp_counted_base_w32.hpp
13 // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
14 // Copyright 2004-2005 Peter Dimov
16 // Distributed under the Boost Software License, Version 1.0. (See
17 // accompanying file LICENSE_1_0.txt or copy at
18 // http://www.boost.org/LICENSE_1_0.txt)
21 // Lock-free algorithm by Alexander Terekhov
23 // Thanks to Ben Hitchings for the #weak + (#shared != 0)
27 #include <boost/detail/interlocked.hpp>
40 sp_counted_base( sp_counted_base const & );
41 sp_counted_base & operator= ( sp_counted_base const & );
43 long use_count_; // #shared
44 long weak_count_; // #weak + (#shared != 0)
48 sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
52 virtual ~sp_counted_base() // nothrow
56 // dispose() is called when use_count_ drops to zero, to release
57 // the resources managed by *this.
59 virtual void dispose() = 0; // nothrow
61 // destroy() is called when weak_count_ drops to zero.
63 virtual void destroy() // nothrow
68 virtual void * get_deleter( std::type_info const & ti ) = 0;
72 BOOST_INTERLOCKED_INCREMENT( &use_count_ );
75 bool add_ref_lock() // true on success
79 long tmp = static_cast< long const volatile& >( use_count_ );
80 if( tmp == 0 ) return false;
81 if( BOOST_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true;
85 void release() // nothrow
87 if( BOOST_INTERLOCKED_DECREMENT( &use_count_ ) == 0 )
94 void weak_add_ref() // nothrow
96 BOOST_INTERLOCKED_INCREMENT( &weak_count_ );
99 void weak_release() // nothrow
101 if( BOOST_INTERLOCKED_DECREMENT( &weak_count_ ) == 0 )
107 long use_count() const // nothrow
109 return static_cast<long const volatile &>( use_count_ );
113 } // namespace detail
117 #endif // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED