public static ZonePacket Parse(ref byte[] rawData, Int32 secureKey)
{
xorBytes(ref rawData, secureKey);
var parsedPacket = new ZonePacket();
if (rawData.Length < 16)
{
throw new NotEnoughBytesException();
// not enough bytes, even for the header
}
parsedPacket.Signature = BitConverter.ToInt32(rawData, 0);
parsedPacket.Size = BitConverter.ToInt32(rawData, 4);
parsedPacket.SequenceID = BitConverter.ToInt32(rawData, 8);
parsedPacket.CRC = BitConverter.ToInt32(rawData, 12);
parsedPacket.Data = new byte[parsedPacket.Size];
if (parsedPacket.Data.Length > rawData.Length - 16)
{
throw new NotEnoughBytesException();
// not enough bytes to parse message. This can happen. What do to?
}
else
{
Array.Copy(rawData, 16, parsedPacket.Data, 0, parsedPacket.Data.Length);
if (rawData.Length - (parsedPacket.Size + 16) > 0)
{
// This means the packets were nagled, and the key was applied to ending bytes unnecessarily
xorBytesFixTail(ref parsedPacket.Data, secureKey);
}
}
// remove from rawData the parsed ZonePacket
Array.Reverse(rawData);
Array.Resize(ref rawData, rawData.Length - (parsedPacket.Size + 16));
Array.Reverse(rawData);
xorBytes(ref rawData, secureKey);
// Check CRC
byte[] computingCRC = new byte[] { 0x12, 0x34, 0x43, 0x21 };
for (int i = 0; i < parsedPacket.Data.Length / 4; i++)
{
computingCRC[0] ^= parsedPacket.Data[i * 4];
computingCRC[1] ^= parsedPacket.Data[i * 4 + 1];
computingCRC[2] ^= parsedPacket.Data[i * 4 + 2];
computingCRC[3] ^= parsedPacket.Data[i * 4 + 3];
}
Array.Reverse(computingCRC, 0, 4);
Int32 computedCRC = BitConverter.ToInt32(computingCRC, 0);
if (computedCRC != parsedPacket.CRC)
{
throw new CRCMismatchException(parsedPacket, computedCRC);
}
return(parsedPacket);
}
public static ZonePacket?TryParse(byte[] rawData, Int32 secureKey)
{
try
{
return(ZonePacket.Parse(ref rawData, secureKey));
}
catch
{
return(null);
}
}
public static Message Parse(ZonePacket Packet)
{
return(Message.Parse(Packet.Data));
}
public CRCMismatchException(ZonePacket ParsedPacket, Int32 ComputedCRC)
{
this.ParsedPacket = ParsedPacket;
this.ComputedCRC = ComputedCRC;
}
