int avail = in.available();
			if(avail == 0) return false;

			if(packetType == -1) {
				packetType = in.read() & 0xff;
				if(inStreamDecryption != null)
					packetType = packetType - inStreamDecryption.getNextKey() & 0xff;
				packetSize = packetSizes[packetType];
				avail--;
            		}
			if(packetSize == -1) {
				if(avail > 0) {
					// this is a variable size packet, the next byte containing the length of said
					packetSize = in.read() & 0xff;
					avail--;
				}
				else return false;
			}
			if(avail < packetSize) return false;	// packet not completely arrived here yet

			fillInStream(packetSize);