#ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SYNC_HPP_INCLUDED | |
#define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SYNC_HPP_INCLUDED | |
// MS compatible compilers support #pragma once | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
// detail/sp_counted_base_sync.hpp - g++ 4.1+ __sync intrinsics | |
// | |
// Copyright (c) 2007 Peter Dimov | |
// | |
// 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 | |
#include <boost/detail/sp_typeinfo.hpp> | |
#include <limits.h> | |
#if defined( __ia64__ ) && defined( __INTEL_COMPILER ) | |
# include <ia64intrin.h> | |
#endif | |
namespace boost | |
{ | |
namespace detail | |
{ | |
#if INT_MAX >= 2147483647 | |
typedef int sp_int32_t; | |
#else | |
typedef long sp_int32_t; | |
#endif | |
inline void atomic_increment( sp_int32_t * pw ) | |
{ | |
__sync_fetch_and_add( pw, 1 ); | |
} | |
inline sp_int32_t atomic_decrement( sp_int32_t * pw ) | |
{ | |
return __sync_fetch_and_add( pw, -1 ); | |
} | |
inline sp_int32_t atomic_conditional_increment( sp_int32_t * pw ) | |
{ | |
// long r = *pw; | |
// if( r != 0 ) ++*pw; | |
// return r; | |
sp_int32_t r = *pw; | |
for( ;; ) | |
{ | |
if( r == 0 ) | |
{ | |
return r; | |
} | |
sp_int32_t r2 = __sync_val_compare_and_swap( pw, r, r + 1 ); | |
if( r2 == r ) | |
{ | |
return r; | |
} | |
else | |
{ | |
r = r2; | |
} | |
} | |
} | |
class sp_counted_base | |
{ | |
private: | |
sp_counted_base( sp_counted_base const & ); | |
sp_counted_base & operator= ( sp_counted_base const & ); | |
sp_int32_t use_count_; // #shared | |
sp_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_ ) == 1 ) | |
{ | |
dispose(); | |
weak_release(); | |
} | |
} | |
void weak_add_ref() // nothrow | |
{ | |
atomic_increment( &weak_count_ ); | |
} | |
void weak_release() // nothrow | |
{ | |
if( atomic_decrement( &weak_count_ ) == 1 ) | |
{ | |
destroy(); | |
} | |
} | |
long use_count() const // nothrow | |
{ | |
return const_cast< sp_int32_t const volatile & >( use_count_ ); | |
} | |
}; | |
} // namespace detail | |
} // namespace boost | |
#endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_SYNC_HPP_INCLUDED |