public byte[] encode(int seq, byte[] cmd)
{
var msglen = MESSAGE_MIN + cmd.Length;
seq = seq & MESSAGE_SEQ_MASK | MESSAGE_DEST;
var @out = new List <byte> {
(byte)msglen,
(byte)seq
};
@out.AddRange(cmd);
@out.AddRange(BitConverter.GetBytes((short)SerialUtil.Crc16_ccitt(@out.ToArray())));
@out.Add(MESSAGE_SYNC);
return(@out.ToArray());
}
public object check_packet(byte[] s)
{
if (s.Length < MESSAGE_MIN)
{
return(0);
}
var msglen = s[MESSAGE_POS_LEN];
if (msglen < MESSAGE_MIN || msglen > MESSAGE_MAX)
{
return(-1);
}
var msgseq = s[MESSAGE_POS_SEQ];
if ((msgseq & ~MESSAGE_SEQ_MASK) != MESSAGE_DEST)
{
return(-1);
}
if (s.Length < msglen)
{
// Need more data
return(0);
}
if (s[msglen - MESSAGE_TRAILER_SYNC] != MESSAGE_SYNC)
{
return(-1);
}
var msgcrc = BitConverter.ToInt16(s, msglen - MESSAGE_TRAILER_CRC);
var crc = SerialUtil.Crc16_ccitt(new ReadOnlySpan <byte>(s, 0, msglen - MESSAGE_TRAILER_SIZE));
if (crc != msgcrc)
{
logging.Debug("got crc {0} vs {1}", crc, msgcrc);
return(-1);
}
return(msglen);
}
