/***************************************************************************
** Get address of region(s) from which we can read data.
** If the region is contiguous, size2 will be zero.
** If non-contiguous, size2 will be the size of second region.
** Returns room available to be read or elementCount, whichever is smaller.
*/
ring_buffer_size_t PaUtil_GetRingBufferReadRegions( PaUtilRingBuffer *rbuf, ring_buffer_size_t elementCount,
void **dataPtr1, ring_buffer_size_t *sizePtr1,
void **dataPtr2, ring_buffer_size_t *sizePtr2 )
{
ring_buffer_size_t index;
ring_buffer_size_t available = PaUtil_GetRingBufferReadAvailable( rbuf ); /* doesn't use memory barrier */
if( elementCount > available ) elementCount = available;
/* Check to see if read is not contiguous. */
index = rbuf->readIndex & rbuf->smallMask;
if( (index + elementCount) > rbuf->bufferSize )
{
/* Write data in two blocks that wrap the buffer. */
ring_buffer_size_t firstHalf = rbuf->bufferSize - index;
*dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
*sizePtr1 = firstHalf;
*dataPtr2 = &rbuf->buffer[0];
*sizePtr2 = elementCount - firstHalf;
}
else
{
*dataPtr1 = &rbuf->buffer[index*rbuf->elementSizeBytes];
*sizePtr1 = elementCount;
*dataPtr2 = NULL;
*sizePtr2 = 0;
}
if( available )
PaUtil_ReadMemoryBarrier(); /* (read-after-read) => read barrier */
return elementCount;
}
// This function returns true if the queue is full, i.e. if it contains the max number
// of elements given to the constructor, false otherwise.
bool MAGE::LabelQueue::isFull( void )
{
PaUtil_ReadMemoryBarrier();
if( nOfLabels >= queue.size() )
return true;
else
return false;
}
// accessors
// This function returns true if the queue is empty, false otherwise.
bool MAGE::LabelQueue::isEmpty( void )
{
PaUtil_ReadMemoryBarrier();
if( nOfLabels <= 0 )
return true;
else
return false;
}
/***************************************************************************
** Return number of elements available for reading. */
ring_buffer_size_t PaUtil_GetRingBufferReadAvailable( PaUtilRingBuffer *rbuf )
{
PaUtil_ReadMemoryBarrier();
return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask );
}
/***************************************************************************
** Return number of bytes available for reading. */
long PaUtil_GetShmRingBufferReadAvailable( PaUtilShmRingBuffer *rbuf )
{
PaUtil_ReadMemoryBarrier();
return ( (rbuf->writeIndex - rbuf->readIndex) & rbuf->bigMask );
}
