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- #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED
- #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED
- // MS compatible compilers support #pragma once
- #if defined(_MSC_VER) && (_MSC_VER >= 1020)
- # pragma once
- #endif
- //
- // detail/sp_counted_base_cw_x86.hpp - CodeWarrion on 486+
- //
- // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
- // Copyright 2004-2005 Peter Dimov
- // Copyright 2005 Rene Rivera
- //
- // 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/smart_ptr/detail/sp_typeinfo_.hpp>
- #include <boost/config.hpp>
- namespace boost
- {
- namespace detail
- {
- inline int atomic_exchange_and_add( int * pw, int dv )
- {
- // int r = *pw;
- // *pw += dv;
- // return r;
- asm
- {
- mov esi, [pw]
- mov eax, dv
- lock xadd dword ptr [esi], eax
- }
- }
- inline void atomic_increment( int * pw )
- {
- //atomic_exchange_and_add( pw, 1 );
- asm
- {
- mov esi, [pw]
- lock inc dword ptr [esi]
- }
- }
- inline int atomic_conditional_increment( int * pw )
- {
- // int rv = *pw;
- // if( rv != 0 ) ++*pw;
- // return rv;
- asm
- {
- mov esi, [pw]
- mov eax, dword ptr [esi]
- L0:
- test eax, eax
- je L1
- mov ebx, eax
- inc ebx
- lock cmpxchg dword ptr [esi], ebx
- jne L0
- L1:
- }
- }
- class BOOST_SYMBOL_VISIBLE sp_counted_base
- {
- private:
- sp_counted_base( sp_counted_base const & );
- sp_counted_base & operator= ( sp_counted_base const & );
- int use_count_; // #shared
- int 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;
- virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0;
- virtual void * get_untyped_deleter() = 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_exchange_and_add( &use_count_, -1 ) == 1 )
- {
- dispose();
- weak_release();
- }
- }
- void weak_add_ref() // nothrow
- {
- atomic_increment( &weak_count_ );
- }
- void weak_release() // nothrow
- {
- if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 )
- {
- destroy();
- }
- }
- long use_count() const // nothrow
- {
- return static_cast<int const volatile &>( use_count_ );
- }
- };
- } // namespace detail
- } // namespace boost
- #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED
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