public void unreadFrame() throws BitstreamException
	{
		if (wordpointer==-1 && bitindex==-1 && (framesize>0))
		{
			try
			{
				source.unread(frame_bytes, 0, framesize);
			}
			catch (IOException ex)
			{
				throw newBitstreamException(STREAM_ERROR);
			}
		}
	}