refc.cpp

/// Increase the reference count on the object.
 
template< class T, class DeletePolicy >
inline void ThreadSafeRefCount< T, DeletePolicy >::addRef()
{
   dFetchAndAdd( mRefCount, 2 );
}
 
/// Decrease the object's reference count and delete the object, if the count
/// drops to zero and claiming the object by the current thread succeeds.
 
template< class T, class DeletePolicy >
inline void ThreadSafeRefCount< T, DeletePolicy >::release()
{
   AssertFatal( mRefCount != 0, "ThreadSafeRefCount::release() - refcount of zero" );
   if( decrementAndTestAndSet( mRefCount ) != 0 )
      DeletePolicy::destroy( ( T* ) this );
}
 
/// Decrement the given reference count.  Return 1 if the count dropped to zero
/// and the claim bit has been successfully set; return 0 otherwise.
 
template< class T, class DeletePolicy >
U32 ThreadSafeRefCount< T, DeletePolicy >::decrementAndTestAndSet( U32& refCount )
{
   U32 oldVal;
   U32 newVal;
 
   do
   {
      oldVal = refCount;
      newVal = oldVal - 2;
 
      AssertFatal( oldVal >= 2,
         "ThreadSafeRefCount::decrementAndTestAndSet() - invalid refcount" );
 
      if( newVal == 0 )
         newVal = 1;
   }
   while( !dCompareAndSwap( refCount, oldVal, newVal ) );
 
   return ( ( oldVal - newVal ) & 1 );
}