func orderToStr(order OrderMessage) string {
str := string(order.Type) + "0" + strconv.Itoa(int(order.SenderID)) + strconv.Itoa(int(order.Floor)) + strconv.Itoa(int(order.Direction))
crc := crc16.Crc16([]byte(str))
// HAXHAX bitshift and convert to byte slice -> string
str += string([]byte{byte((crc >> 8) & 0xff), byte(crc & 0xff)})
return str
}
func strToOrder(str string) OrderMessage {
// Check for CRC mismatch. Not tamper-proof, but should be corruption-proof.
calculatedCrc := crc16.Crc16([]byte(str[:6]))
receivedCrc := (uint16(str[6]) << 8) + uint16(str[7])
if calculatedCrc != receivedCrc {
log.Error("CRC mismatch in " + str[:4] + " message!")
return OrderMessage{Type: InvalidOrder} // Probably corrupted
}
senderID, _ := strconv.Atoi(string(str[3]))
floorNum, _ := strconv.Atoi(string(str[4]))
dirNum, _ := strconv.Atoi(string(str[5]))
return OrderMessage{Type: OrderType(str[:2]), SenderID: uint(senderID), Floor: driver.Floor(floorNum), Direction: driver.Direction(dirNum)}
}
// redis cluster uses CRC16 + modulo to determine a key's slot
func keySlot(key string) uint16 {
cs := crc16.Crc16([]byte(key))
return cs % redisSlotMax
}