// given a packet body only (no checksum), packs it
// and sends.
public override void Send(string packetBodyOut)
{
string strToSend = packetBodyOut + NmeaPacket.checksum(packetBodyOut);
logPacket("sending packet=" + strToSend);
base.Send(strToSend);
if (m_handshake)
{
try
{
string csResponse = base.Receive();
log(String.Format("received handshake response: {0}", csResponse));
// watch for "UNABLE" responses, indicating invalid route linkage (0 length leg) etc:
if (csResponse.StartsWith("$PMGNCMD,UNABLE"))
{
m_errorCount++;
}
}
catch (CommPortException e)
{
logError("exception waiting for handshake response: " + e.Message);
base.Open();
}
}
}
public void Receive(MPacketReceived packetIn)
{
packetIn.isGood = false;
int tries = 0;
while (!packetIn.isGood && tries++ <= 3)
{
//log("Receive() - waiting... try " + tries);
packetIn.m_string = base.Receive();
//log("received: " + packetIn.m_string);
if (packetIn.m_string.StartsWith("$PMGNCSM"))
{
log("received astray CSM: " + packetIn.m_string);
tries--;
continue;
}
if (m_handshake)
{
string cs = NmeaPacket.checksumReceived(packetIn.m_string);
MPacketCsm packet = new MPacketCsm(cs);
string str = packet.ToString() + NmeaPacket.checksum(packet.ToString());
log("sending handshake response: " + str);
base.Send(str);
}
if (!NmeaPacket.checksumVerify(packetIn.m_string))
{
packetIn.isGood = false;
if (m_handshake)
{
logError("bad checksum, waiting for resent packet");
}
else
{
logError("bad checksum, returning bad packet");
break; // just report the received package, isGood = false
}
}
else
{
packetIn.isGood = packetIn.basicParse(packetIn.m_string);
// packet is good and parsed, so the fields array is filled
}
}
logPacket("received " + (packetIn.isGood?"good":"bad") + " packet=" + packetIn);
}
