1 #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
2 #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED
4 // MS compatible compilers support #pragma once
6 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
11 // detail/sp_counted_base_gcc_x86.hpp - g++ on 486+ or AMD64
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/sp_typeinfo.hpp>
35 inline int atomic_exchange_and_add( int * pw, int dv )
47 "=m"( *pw ), "=r"( r ): // outputs (%0, %1)
48 "m"( *pw ), "1"( dv ): // inputs (%2, %3 == %1)
49 "memory", "cc" // clobbers
55 inline void atomic_increment( int * pw )
57 //atomic_exchange_and_add( pw, 1 );
63 "=m"( *pw ): // output (%0)
64 "m"( *pw ): // input (%1)
69 inline int atomic_conditional_increment( int * pw )
72 // if( rv != 0 ) ++*pw;
81 "test %%eax, %%eax\n\t"
89 "=m"( *pw ), "=&a"( rv ), "=&r"( tmp ): // outputs (%0, %1, %2)
90 "m"( *pw ): // input (%3)
101 sp_counted_base( sp_counted_base const & );
102 sp_counted_base & operator= ( sp_counted_base const & );
104 int use_count_; // #shared
105 int weak_count_; // #weak + (#shared != 0)
109 sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
113 virtual ~sp_counted_base() // nothrow
117 // dispose() is called when use_count_ drops to zero, to release
118 // the resources managed by *this.
120 virtual void dispose() = 0; // nothrow
122 // destroy() is called when weak_count_ drops to zero.
124 virtual void destroy() // nothrow
129 virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
130 virtual void * get_local_deleter( sp_typeinfo const & ti ) = 0;
131 virtual void * get_untyped_deleter() = 0;
135 atomic_increment( &use_count_ );
138 bool add_ref_lock() // true on success
140 return atomic_conditional_increment( &use_count_ ) != 0;
143 void release() // nothrow
145 if( atomic_exchange_and_add( &use_count_, -1 ) == 1 )
152 void weak_add_ref() // nothrow
154 atomic_increment( &weak_count_ );
157 void weak_release() // nothrow
159 if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
165 long use_count() const // nothrow
167 return static_cast<int const volatile &>( use_count_ );
171 } // namespace detail
175 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_GCC_X86_HPP_INCLUDED