CommandStation-EX/Z21Throttle.cpp

/*
 *  © 2023 Thierry Paris / Locoduino
 *  © 2023,2024 Harald Barth
 *  All rights reserved.
 *  
 *  This file is part of CommandStation-EX
 *
 *  This is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  It is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
 */
#include <Arduino.h>
#include "defines.h"
#include <WiFi.h>
#include "Z21Throttle.h"
#include "DCC.h"
#include "WifiESP32.h"
#include "DCCWaveform.h"
#include "StringFormatter.h"
#include "Turnouts.h"
#include "DIAG.h"
#include "GITHUB_SHA.h"
#include "version.h"
#include "EXRAIL2.h"
#include "CommandDistributor.h"
#include "TrackManager.h"
#include "DCCTimer.h"
#ifdef USE_HMI
	#include "hmi.h"
#endif

static std::vector<NetworkClientUDP> clientsUDP; // a list to hold all UDP clients

Z21Throttle *Z21Throttle::firstThrottle=NULL;
byte Z21Throttle::commBuffer[100];
byte Z21Throttle::replyBuffer[20];

Z21Throttle* Z21Throttle::readWriteThrottle = NULL;
int Z21Throttle::cvAddress = -1;
int Z21Throttle::cvValue = -1;

void printClientsUDP();

WiFiUDP NetworkClientUDP::client;

#define LOOPLOCOS(THROTTLECHAR, CAB)  for (int loco=0;loco<MAX_MY_LOCO;loco++) \
      if ((myLocos[loco].throttle==THROTTLECHAR || '*'==THROTTLECHAR) && (CAB<0 || myLocos[loco].cab==CAB))

void Z21Throttle::setup(IPAddress ip, int port) {
	uint8_t ret = NetworkClientUDP::client.begin(ip, port);
    if(ret == 1) DIAG(F("UDP Connection started port %d. Z21 apps are available."), port);
    else DIAG(F("UDP Connection failed. Z21 apps not available."));
	NetworkClientUDP::client.flush();
}

void Z21Throttle::loop() {
  int clientId = 0;
  byte networkPacket[MAX_MTU] = {0};

  int len = NetworkClientUDP::client.parsePacket();
  if (len > MAX_MTU) {
    DIAG(F("ERROR: len > MAX_MTU"));
    return;
  }
  IPAddress remoteIP = NetworkClientUDP::client.remoteIP();
  int remotePort =  NetworkClientUDP::client.remotePort();
  if (len > 0) {
    for (clientId = 0; clientId < clientsUDP.size(); clientId++) {
      if (clientsUDP[clientId].inUse) {
	if (clientsUDP[clientId].remoteIP == remoteIP
	    && clientsUDP[clientId].remotePort == remotePort) {
	  //if (Diag::Z21THROTTLEVERBOSE) DIAG(F("UDP client %d : %s Already connected"), clientId, clientsUDP[clientId].remoteIP.toString().c_str());
	  break;
	}
      }
    }
    
    if (clientId >= clientsUDP.size()) { // not found, let's create it
      NetworkClientUDP nc;
      nc.remoteIP = NetworkClientUDP::client.remoteIP();
      nc.remotePort = NetworkClientUDP::client.remotePort();
      nc.connected = true;
      nc.inUse = true;
      
      clientsUDP.push_back(nc);
      if (Diag::Z21THROTTLE) DIAG(F("New UDP client %d, %s"), clientId, nc.remoteIP.toString().c_str());
      printClientsUDP();
#ifdef USE_HMI
      if (hmi::CurrentInterface != NULL) hmi::CurrentInterface->NewClient(clientId, nc.remoteIP, 0);
#endif
      // Fleischmann/Roco Android app starts with Power on !
      // XXX this is the wrong place to do this
      TrackManager::setMainPower(POWERMODE::ON);
    }
    
    // now clientId is on "current client", either new or old
    
    int l = NetworkClientUDP::client.read(networkPacket, len);
    if (l != len) {
      DIAG(F(" l %d = len %d"), l, len);
      return;
    }
    
    Z21Throttle* pThrottle = getOrAddThrottle(clientId); 
    if (pThrottle != NULL)
      pThrottle->parse(networkPacket, len);
   }
}

// Print the list of assigned locomotives
void Z21Throttle::printLocomotives(bool addTab) {
	if (!Diag::Z21THROTTLE)
		return;

	DIAG(F("      Locomotives ------------------"));
	for (int loco = 0; loco < MAX_MY_LOCO; loco++)
		if (myLocos[loco].throttle != '\0')
			DIAG(F("%s         %d : cab %d on throttle %c"), addTab ? "   ":"", loco, myLocos[loco].cab, myLocos[loco].throttle);
}

// Print the list of UDP clients
void printClientsUDP() {
	if (!Diag::Z21THROTTLE) return;

	DIAG(F("      UDP Clients ------------------"));
	for (int clientId = 0; clientId < clientsUDP.size(); clientId++)
		if (clientsUDP[clientId].ok())
			DIAG(F("         %d %s: %s:%d"), clientId, clientsUDP[clientId].connected?"Connected":"Not connected", clientsUDP[clientId].remoteIP.toString().c_str(), clientsUDP[clientId].remotePort);
		else
			DIAG(F("         %d unused"), clientId);
}

// Print the list of throttles
void Z21Throttle::printThrottles(bool inPrintLocomotives) {
	if (!Diag::Z21THROTTLE)	return;

	DIAG(F("      Z21 Throttles ---------------"));
	for (Z21Throttle* wt = firstThrottle; wt != NULL; wt = wt->nextThrottle) {
		if (wt->clientid == -1)
			DIAG(F("         unused"));
		else {
			DIAG(F("         %d : %d.%d.%d.%d:%d"), wt->clientid, 
			clientsUDP[wt->clientid].remoteIP[0], 
			clientsUDP[wt->clientid].remoteIP[1], 
			clientsUDP[wt->clientid].remoteIP[2], 
			clientsUDP[wt->clientid].remoteIP[3], 
			clientsUDP[wt->clientid].remotePort);

			if (inPrintLocomotives)
				wt->printLocomotives(true);
		}
	}
}

Z21Throttle* Z21Throttle::getOrAddThrottle(int clientId) {
	for (Z21Throttle* wt = firstThrottle; wt != NULL ; wt = wt->nextThrottle)  {
		if (wt->clientid == clientId)
			return wt; 
	}

	Z21Throttle *p = new Z21Throttle(clientId);
	printThrottles(false);
	return p;
}

void Z21Throttle::forget( byte clientId) {
	for (Z21Throttle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle)  
    	if (wt->clientid==clientId) {
			delete wt;
			break; 
		}
}

bool Z21Throttle::isThrottleInUse(int cab) {
	for (Z21Throttle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle)  
		if (wt->areYouUsingThrottle(cab)) return true;

	return false;
}

bool Z21Throttle::areYouUsingThrottle(int cab) {
	LOOPLOCOS('*', cab) { // see if I have this cab in use
		return true;
	}

	return false;
}

// One instance of Z21Throttle per connected client, so we know what the locos are 
 
Z21Throttle::Z21Throttle(int inClientId) {
        clientid = inClientId;
	if (Diag::Z21THROTTLE) DIAG(F("New Z21Throttle for client UDP %d"), clientid); 
	nextThrottle=firstThrottle;
	firstThrottle= this;
	initSent=false; // prevent sending heartbeats before connection completed
	turnoutListHash = -1;  // make sure turnout list is sent once
	exRailSent=false;
	mostRecentCab=0;     
	for (int loco=0;loco<MAX_MY_LOCO; loco++)
		myLocos[loco].throttle='\0';
}

Z21Throttle::~Z21Throttle() {
	if (Diag::Z21THROTTLE) DIAG(F("Deleting Z21Throttle client UDP %d"),this->clientid);
	if (firstThrottle== this) {
		firstThrottle=this->nextThrottle;
		return;
	}

	for (Z21Throttle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle) {
		if (wt->nextThrottle==this) {
			wt->nextThrottle=this->nextThrottle;
			return;  
		}
	}
}

void Z21Throttle::write(byte* inpData, int inLengthData) {
	size_t size = 0;

//	if (this->dontReply)
//		return;
	
	NetworkClientUDP::client.beginPacket(clientsUDP[this->clientid].remoteIP, clientsUDP[this->clientid].remotePort);
	size = NetworkClientUDP::client.write(inpData, inLengthData);
	NetworkClientUDP::client.endPacket();

	if (Diag::Z21THROTTLEDATA && inpData[0] != 0x14 && inpData[2] != 0x84 ) DIAG(F("Z21 Throttle %d : %s SENT 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x"), clientid,
                          size == 0 ? "BINARY NOT" :"",
                          (inLengthData > 0)?inpData[0]:0,
                          (inLengthData > 1)?inpData[1]:0,
                          (inLengthData > 2)?inpData[2]:0,
                          (inLengthData > 3)?inpData[3]:0,
                          (inLengthData > 4)?inpData[4]:0,
                          (inLengthData > 5)?inpData[5]:0,
                          (inLengthData > 6)?inpData[6]:0,
                          (inLengthData > 7)?inpData[7]:0,
                          (inLengthData > 8)?inpData[8]:0,
                          (inLengthData > 9)?inpData[9]:0);
}

// sizes : [       2        ][       2        ][inLengthData]
// bytes : [length1, length2][Header1, Header2][Data........]
bool Z21Throttle::notify(unsigned int inHeader, byte* inpData, unsigned int inLengthData, bool inXorInData) {
	int realLength = (inLengthData + 4 + (inXorInData == false ? 1 : 0));

	Z21Throttle::commBuffer[0] = realLength % 256;
	Z21Throttle::commBuffer[1] = realLength / 256;
	Z21Throttle::commBuffer[2] = inHeader % 256;
	Z21Throttle::commBuffer[3] = inHeader / 256;
	memcpy(Z21Throttle::commBuffer + 4, inpData, inLengthData);

	if (!inXorInData) {    // if xor byte not included in data, compute and write it !
		byte xxor = 0;

		for (unsigned int i = 0; i < inLengthData; i++)
			xxor ^= inpData[i];

		Z21Throttle::commBuffer[inLengthData+4] = xxor;
	}

	write(Z21Throttle::commBuffer, realLength);

	return true;
}

// sizes : [       2        ][       2        ][   1   ][inLengthData]
// bytes : [length1, length2][Header1, Header2][XHeader][Data........]
bool Z21Throttle::notify(unsigned int inHeader, unsigned int inXHeader, byte* inpData, unsigned int inLengthData, bool inXorInData) {
	int realLength = (inLengthData + 5 + (inXorInData == false ? 1 : 0));

	Z21Throttle::commBuffer[0] = realLength % 256;
	Z21Throttle::commBuffer[1] = realLength / 256;
	Z21Throttle::commBuffer[2] = inHeader % 256;
	Z21Throttle::commBuffer[3] = inHeader / 256;
	Z21Throttle::commBuffer[4] = inXHeader;
	memcpy(Z21Throttle::commBuffer + 5, inpData, inLengthData);

	if (!inXorInData) {    // if xor byte not included in data, compute and write it !
		byte xxor = inXHeader;

		for (unsigned int i = 0; i < inLengthData; i++)
			xxor ^= inpData[i];

		Z21Throttle::commBuffer[inLengthData + 5] = xxor;
	}

	write(Z21Throttle::commBuffer, realLength);

	return true;
}

// sizes : [       2        ][       2        ][   1   ][ 1 ][inLengthData]
// bytes : [length1, length2][Header1, Header2][XHeader][DB0][Data........]
bool Z21Throttle::notify(unsigned int inHeader, unsigned int inXHeader, byte inDB0, byte* inpData, unsigned int inLengthData, bool inXorInData) {
	int realLength = (inLengthData + 6 + (inXorInData == false ? 1 : 0));

	Z21Throttle::commBuffer[0] = realLength % 256;
	Z21Throttle::commBuffer[1] = realLength / 256;
	Z21Throttle::commBuffer[2] = inHeader % 256;
	Z21Throttle::commBuffer[3] = inHeader / 256;
	Z21Throttle::commBuffer[4] = inXHeader;
	Z21Throttle::commBuffer[5] = inDB0;
	memcpy(Z21Throttle::commBuffer + 6, inpData, inLengthData);

	if (!inXorInData) {   // if xor byte not included in data, compute and write it !
		byte xxor = inXHeader^inDB0;

		for (unsigned int i = 0; i < inLengthData; i++)
			xxor ^= inpData[i];

		Z21Throttle::commBuffer[inLengthData + 6] = xxor;
	}

	write(Z21Throttle::commBuffer, realLength);

	return true;
}

void Z21Throttle::notifyStatus() {
	Z21Throttle::replyBuffer[0] = 0;	// main current 1
	Z21Throttle::replyBuffer[1] = 0; // main current 2
	Z21Throttle::replyBuffer[2] = 0; // prog current 1
	Z21Throttle::replyBuffer[3] = 0; // prog current 2
	Z21Throttle::replyBuffer[4] = 0; // filtered main current 1
	Z21Throttle::replyBuffer[5] = 0; // filtered main current 2
	Z21Throttle::replyBuffer[6] = 0; // Temperature 1
	Z21Throttle::replyBuffer[7] = 0; // Temperature 2
	Z21Throttle::replyBuffer[8] = 5; // Supply voltage 1
	Z21Throttle::replyBuffer[9] = 0; // supply voltage 2
	Z21Throttle::replyBuffer[10] = 16; // VCC voltage 1 
	Z21Throttle::replyBuffer[11] = 0; // VCC voltage 2
	Z21Throttle::replyBuffer[12] = 0b00000000;	// CentralState 
	Z21Throttle::replyBuffer[13] = 0b00000000; // CentralStateEx
	Z21Throttle::replyBuffer[14] = 0;
	Z21Throttle::replyBuffer[15] = 0;
	notify(HEADER_LAN_SYSTEMSTATE, Z21Throttle::replyBuffer, 16, true);
}

int Z21Throttle::getOrAddLoco(int cab) {
	int loco = 0;
	for (; loco < MAX_MY_LOCO; loco++) {
		if (myLocos[loco].throttle != '\0' && myLocos[loco].cab == cab) 
			return loco;
	}

	if (loco >= MAX_MY_LOCO) {
		//use first empty "slot" on this client's list, will be added to DCC registration list
		for (int locoToAdd = 0; locoToAdd < MAX_MY_LOCO; locoToAdd++) {
			if (myLocos[locoToAdd].throttle == '\0') { 
				myLocos[locoToAdd].throttle = '0' + this->clientid;
				myLocos[locoToAdd].cab = cab; 
				myLocos[locoToAdd].functionMap = DCC::getFunctionMap(cab); 
				myLocos[locoToAdd].broadcastPending = true; // means speed/dir will be sent later
				mostRecentCab = cab;
				myLocos[locoToAdd].functionToggles = 1<<2; // F2 (HORN)  is a non-toggle
				return locoToAdd;
			}
		}
	}

	return -1;  // no loco found, and no place to add one !
}

void Z21Throttle::notifyLocoInfo(byte inMSB, byte inLSB) {
	int locoAddress = ((inMSB & 0x3F) << 8) + inLSB;
	int loco = getOrAddLoco(locoAddress);

	if (loco == -1)
	    return; //'Too many locos !'

	Z21Throttle::replyBuffer[0] = inMSB;	// loco address msb
	Z21Throttle::replyBuffer[1] = inLSB; // loco address lsb
	Z21Throttle::replyBuffer[2] = B00000100; // 0000CKKK	 C = already controlled    KKK = speed steps 000:14, 010:28, 100:128
	Z21Throttle::replyBuffer[3] = DCC::getThrottleSpeed(locoAddress); // RVVVVVVV  R = forward    VVVVVVV = speed
	if (DCC::getThrottleDirection(locoAddress)) bitSet(Z21Throttle::replyBuffer[3], 7);

	uint32_t functionMap = DCC::getFunctionMap(locoAddress);

	// Byte 4: 0DSLFGHJ
	// D = double traction  S = Smartsearch  L = F0  F = F4  G = F3  H = F2  J = F1
	Z21Throttle::replyBuffer[4] = (functionMap >> 1) & 0xF; // function F1 to F5
	if (functionMap & 1) // set F0 (Light)
	  Z21Throttle::replyBuffer[4] += 16;
	functionMap >>=5; // shift out the 5 bits which are not needed any more

	Z21Throttle::replyBuffer[5] = functionMap & 0xFF; // function  F5 to F12;  F5 is bit0
	functionMap >>=8; // shift out 8 more
	Z21Throttle::replyBuffer[6] = functionMap & 0xFF; // function F13 to F20; F13 is bit0
	functionMap >>=8; // shift out 8 more
	Z21Throttle::replyBuffer[7] = functionMap & 0xFF; // function F21 to F28; F21 is bit0
	functionMap >>=8; // shift out 8 more
	Z21Throttle::replyBuffer[8] = functionMap & 0xFF; // function F29 to F31; F28 is bit0

	notify(HEADER_LAN_XPRESS_NET, LAN_X_HEADER_LOCO_INFO, Z21Throttle::replyBuffer, 9, false);
}

void Z21Throttle::notifyTurnoutInfo(byte inMSB, byte inLSB) {
	Z21Throttle::replyBuffer[0] = inMSB;	// turnout address msb
	Z21Throttle::replyBuffer[1] = inLSB; // turnout address lsb
	Z21Throttle::replyBuffer[2] = B00000000; // 000000ZZ	 ZZ : 00 not switched   01 pos1  10 pos2  11 invalid
	notify(HEADER_LAN_XPRESS_NET, LAN_X_HEADER_TURNOUT_INFO, Z21Throttle::replyBuffer, 3, false);
}

void Z21Throttle::notifyLocoMode(byte inMSB, byte inLSB) {
	Z21Throttle::replyBuffer[0] = inMSB;	// loco address msb
	Z21Throttle::replyBuffer[1] = inLSB; // loco address lsb
	Z21Throttle::replyBuffer[2] = B00000000; // 00000000	DCC   00000001 MM
	notify(HEADER_LAN_GET_LOCOMODE, Z21Throttle::replyBuffer, 3, true);
}

void Z21Throttle::notifyFirmwareVersion() {
	Z21Throttle::replyBuffer[0] = 0x01;	// Version major in BCD
	Z21Throttle::replyBuffer[1] = 0x23;	// Version minor in BCD
	notify(HEADER_LAN_XPRESS_NET, LAN_X_HEADER_FIRMWARE_VERSION, 0x0A, Z21Throttle::replyBuffer, 2, false);
}

void Z21Throttle::notifyHWInfo() {
	Z21Throttle::replyBuffer[0] = 0x00;	// Hardware type in BCD on int32
	Z21Throttle::replyBuffer[1] = 0x02;	// Hardware type in BCD on int32
	Z21Throttle::replyBuffer[2] = 0x00;	// Hardware type in BCD on int32
	Z21Throttle::replyBuffer[3] = 0x00;	// Hardware type in BCD on int32
	Z21Throttle::replyBuffer[4] = 0x23;	// Firmware version in BCD on int32
	Z21Throttle::replyBuffer[5] = 0x01;	// Firmware version in BCD on int32
	Z21Throttle::replyBuffer[6] = 0x00;	// Firmware version in BCD on int32
	Z21Throttle::replyBuffer[7] = 0x00;	// Firmware version in BCD on int32
	notify(HEADER_LAN_GET_HWINFO, Z21Throttle::replyBuffer, 8, true);
}

void Z21Throttle::notifyCvNACK(int inCvAddress) {
	Z21Throttle::replyBuffer[0] = highByte(inCvAddress); // cv address msb
	Z21Throttle::replyBuffer[1] = lowByte(inCvAddress); // cv address lsb
	notify(HEADER_LAN_XPRESS_NET, LAN_X_HEADER_CV_NACK, LAN_X_DB0_CV_NACK, Z21Throttle::replyBuffer, 0, false);
}

void Z21Throttle::notifyCvRead(int inCvAddress, int inValue) {
	Z21Throttle::replyBuffer[0] = highByte(inCvAddress); // cv address msb
	Z21Throttle::replyBuffer[1] = lowByte(inCvAddress); // cv address lsb
	Z21Throttle::replyBuffer[2] = inValue; // cv value
	notify(HEADER_LAN_XPRESS_NET, LAN_X_HEADER_CV_RESULT, 0x14, Z21Throttle::replyBuffer, 3, false);
}

void Z21Throttle::setSpeed(byte inNbSteps, byte inDB1, byte inDB2, byte inDB3) {
	bool isForward = bitRead(inDB3, 7);
	byte speed = inDB3;
	bitClear(speed, 7);

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : speed %d"), clientid, speed * (isForward ? 1:-1));

	int locoAddress = ((inDB1 & 0x3F) << 8) + inDB2;

	if (getOrAddLoco(locoAddress) == -1)
    	return;

	DCC::setThrottle(locoAddress, speed, isForward);

	if ((this->broadcastFlags & BROADCAST_BASE) != 0)
		notifyLocoInfo(inDB1, inDB2);
}

//
// TODO Pass through a text message to avoid multi thread locks...
//

void Z21Throttle::setFunction(byte inDB1, byte inDB2, byte inDB3) {
	// inDB3 :  TTNN NNNN		TT:00 off, TT:01 on; TT:10 toggle   NNNNNN function number

	byte action = bitRead(inDB3, 6) + 2 * bitRead(inDB3, 7);
	byte function = inDB3;
	bitClear(function, 6);
	bitClear(function, 7);
	bool activeFlag = action == 0b01;

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : function %d %s"), clientid, function, activeFlag?"ON":"OFF");

	int locoAddress = ((inDB1 & 0x3F) << 8) + inDB2;
	if (getOrAddLoco(locoAddress) == -1)
    	return;

	if (action == 0b10)	{	// toggle
		bool isActivated = DCC::getFn(locoAddress, function);
		activeFlag = !isActivated;
	}

	DCC::setFn(locoAddress, function, activeFlag);
	if ((this->broadcastFlags & BROADCAST_BASE) != 0)
		notifyLocoInfo(inDB1, inDB2);
}

//
// TODO Pass through a text message to avoid multi thread locks...
//

void Z21CvValueCallback(int16_t inValue)
{
	Z21Throttle::cvValue = inValue;

	if (inValue == -1)
		Z21Throttle::readWriteThrottle->notifyCvNACK(Z21Throttle::cvAddress);
	else
		Z21Throttle::readWriteThrottle->notifyCvRead(Z21Throttle::cvAddress, inValue);

	Z21Throttle::readWriteThrottle = NULL;
}

void Z21Throttle::cvReadProg(byte inDB1, byte inDB2) {
	if (Z21Throttle::readWriteThrottle != NULL)
		return;

	int cvAddress = ((inDB1 & 0x3F) << 8) + inDB2 + 1;

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : cvRead Prog %d"), clientid, cvAddress);

	Z21Throttle::readWriteThrottle = this;
	Z21Throttle::cvAddress = cvAddress - 1;

	void (*ptr)(int16_t) = &Z21CvValueCallback;
	DCC::readCV(cvAddress, ptr);
}

// Working as cvReadProg for the moment...
void Z21Throttle::cvReadMain(byte inDB1, byte inDB2) {
	if (Z21Throttle::readWriteThrottle != NULL)
		return;

	int cvAddress = ((inDB1 & 0x3F) << 8) + inDB2 + 1;

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : cvRead Main cv %d"), clientid, cvAddress);

	Z21Throttle::readWriteThrottle = this;
	Z21Throttle::cvAddress = cvAddress - 1;

	void (*ptr)(int16_t) = &Z21CvValueCallback;
	DCC::readCV(cvAddress, ptr);
}

//
// TODO Pass through a text message to avoid multi thread locks...
//

void Z21Throttle::cvWriteProg(byte inDB1, byte inDB2, byte inDB3) {
	if (Z21Throttle::readWriteThrottle != NULL)
		return;

	int cvAddress = ((inDB1 & 0x3F) << 8) + inDB2 + 1;

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : cvWrite Prog cv %d value %d"), clientid, cvAddress, inDB3);

	Z21Throttle::readWriteThrottle = this;
	Z21Throttle::cvAddress = cvAddress - 1;

	void (*ptr)(int16_t) = &Z21CvValueCallback;
	DCC::writeCVByte(cvAddress, inDB3, ptr);
}

// Working as cvReadProg for the moment...
void Z21Throttle::cvReadPom(byte inDB1, byte inDB2, byte inDB3, byte inDB4) {
	if (Z21Throttle::readWriteThrottle != NULL)
		return;

	int locoAddress = ((inDB1 & 0x3F) << 8) + inDB2;
	int cvAddress = ((inDB3 & B00000011) << 8) + inDB4 + 1;

	if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : cvRead Pom Loco %d cv %d"), clientid, locoAddress, cvAddress);

	Z21Throttle::readWriteThrottle = this;
	Z21Throttle::cvAddress = cvAddress - 1;

	void (*ptr)(int16_t) = &Z21CvValueCallback;
	DCC::readCV(cvAddress, ptr);
}

void diagPacket(byte *networkPacket, int len) {
  DIAG(F("len=%d 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x  0x%02x 0x%02x 0x%02x 0x%02x 0x%02x"),
       len,
       networkPacket[0],
       networkPacket[1],
       networkPacket[2],
       networkPacket[3],
       networkPacket[4],
       networkPacket[5],
       networkPacket[6],
       networkPacket[7],
       networkPacket[8],
       networkPacket[9],
       networkPacket[10],
       networkPacket[11],
       networkPacket[12],
       networkPacket[13],
       networkPacket[14]);
}
#define GETINT16(BUF) (int16_t((unsigned char)(*(BUF+1)) << 8 | (unsigned char)(*BUF)));
bool Z21Throttle::parse(byte *networkPacket, int len) {

  bool done = false;

  // same names as in Z21 LAN Protocol Specification
  byte *DB;
  byte *Data;
  byte Xheader;
  int Header;

  byte *p = networkPacket;
  int l = len;

  while (l > 0) {

    int lengthData = GETINT16(p);
    l -= lengthData;
    if (p == networkPacket && lengthData != len) {
      diagPacket(networkPacket, len);
    }
    if (l < 0) {
      DIAG(F("ERROR: Xbus data exceeds UDP packet size: l < 0 pos=%d, l=%d"), p-networkPacket, l);
      diagPacket(networkPacket, len);
      return false;
    }
    if (l > 0 && lengthData < 4) {
      DIAG(F("WARNING: Xbus data does not fill UDP packet size: l > 0 pos=%d, l=%d"), p-networkPacket, l);
      diagPacket(networkPacket, len);
      return true;
    }
    // length of the data = total length - length of length (!) - length of header
    lengthData -= 4;
    if (lengthData < 0) {
      DIAG(F("ERROR: lengthData < 0 SHOULD NOT GET HERE"));
      diagPacket(networkPacket, len);
      return false;
    }
    p += 2;
    Header = GETINT16(p);
    p += 2;
    // now p is at start of Data, networkPacket + 4
    Data = p;
    Xheader = Data[0];
    DB = Data + 1;
    int nbLocos = CountLocos();
    // set p for next round
    p += lengthData;
    if (Diag::Z21THROTTLEDATA &&
	!((DB[0] == LAN_X_DB0_GET_STATUS) && (Xheader == LAN_X_HEADER_GENERAL)))
      DIAG(F("%d <- lengthData:%d  Header:0x%02x  : 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x"),
	   this->clientid, lengthData, Header,
	   (lengthData > 0)?Data[0]:0,
	   (lengthData > 1)?Data[1]:0,
	   (lengthData > 2)?Data[2]:0,
	   (lengthData > 3)?Data[3]:0,
	   (lengthData > 4)?Data[4]:0,
	   (lengthData > 5)?Data[5]:0,
	   (lengthData > 6)?Data[6]:0,
	   (lengthData > 7)?Data[7]:0,
	   (lengthData > 8)?Data[8]:0,
	   (lengthData > 9)?Data[9]:0);
    if (l > 0 && Diag::Z21THROTTLEDATA) DIAG(F("next packet follows"));
    
    switch (Header)	{
    case HEADER_LAN_XPRESS_NET:
      switch (Xheader) {
      case LAN_X_HEADER_GENERAL:
	switch (DB[0]) {
	case LAN_X_DB0_GET_VERSION:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d GET_VERSION"), this->clientid);
	  break;
	case LAN_X_DB0_GET_STATUS:
	  if (false && Diag::Z21THROTTLEVERBOSE) DIAG(F("%d GET_STATUS  "), this->clientid);
	  notifyStatus();
	  done = true;
	  break;
	case LAN_X_DB0_SET_TRACK_POWER_OFF:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d POWER_OFF"), this->clientid);
	  //
	  // TODO Pass through a text message to avoid multi thread locks...
	  //
	  TrackManager::setMainPower(POWERMODE::OFF);
	  done = true;
	  break;
	case LAN_X_DB0_SET_TRACK_POWER_ON:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d POWER_ON"), this->clientid);
	  //
	  // TODO Pass through a text message to avoid multi thread locks...
	  //
	  TrackManager::setMainPower(POWERMODE::ON);
	  done = true;
	  break;
	}
	break;
      case LAN_X_HEADER_SET_STOP:
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d EMERGENCY_STOP"), this->clientid);
	//
	// TODO Pass through a text message to avoid multi thread locks...
	//
	//Emergency Stop  (speed code 1)
	// setThrottle will cause a broadcast so notification will be sent
	LOOPLOCOS('*', 0) { DCC::setThrottle(myLocos[loco].cab, 1, DCC::getThrottleDirection(myLocos[loco].cab)); }
	done = true;
	break;
      case LAN_X_HEADER_SET_LOCO:
	switch (DB[0]) {
	case LAN_X_DB0_LOCO_DCC14:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOCO DCC 14 SPEED"), this->clientid);
	  setSpeed(14, DB[1], DB[2], DB[3]);
	  done = true;
	  break;
	case LAN_X_DB0_LOCO_DCC28:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOCO DCC 28 SPEED"), this->clientid);
	  setSpeed(28, DB[1], DB[2], DB[3]);
	  done = true;
	  break;
	case LAN_X_DB0_LOCO_DCC128:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOCO DCC 128 SPEED"), this->clientid);
	  setSpeed(128, DB[1], DB[2], DB[3]);
	  done = true;
	  break;
	case LAN_X_DB0_SET_LOCO_FUNCTION:
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOCO DCC FUNCTION"), this->clientid);
	  setFunction(DB[1], DB[2], DB[3]);
	  if (Diag::Z21THROTTLE) {
	    // Debug capacity to print data...
	    byte function = DB[3];
	    bitClear(function, 6);
	    bitClear(function, 7);
	    if (function == 12) { // why not ?
	      printClientsUDP();
	      printThrottles(true);
	    }
	  }
	  done = true;
	  break;
	}
	break;
      case LAN_X_HEADER_GET_LOCO_INFO:
	// XXX Should we switch(DB[0]) here?
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOCO INFO: "), this->clientid);
	notifyLocoInfo(DB[1], DB[2]);
	done = true;
	
	break;
      case LAN_X_HEADER_GET_TURNOUT_INFO:
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d TURNOUT INFO  "), this->clientid);
	notifyTurnoutInfo(DB[0], DB[1]);
	done = true;
	
	break;
      case LAN_X_HEADER_GET_FIRMWARE_VERSION:
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d FIRMWARE VERSION  "), this->clientid);
	notifyFirmwareVersion();
	done = true;
	break;
      case LAN_X_HEADER_CV_READ:
	if (TrackManager::getProgDriver() != NULL) {
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d CV READ PROG "), this->clientid);
	  // DB0 should be 0x11
	  cvReadProg(DB[1], DB[2]);
	}
	else {
	  //
	  // TODO Dont work today...
	  //
	  
	  // If no prog track, read on the main track !
	  if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d CV READ MAIN "), this->clientid);
	  // DB0 should be 0x11
	  cvReadMain(DB[1], DB[2]);
	}
	done = true;
	break;
      case LAN_X_HEADER_CV_POM:
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d CV READ POM"), this->clientid);
	// DB0 should be 0x11
	cvReadPom(DB[1], DB[2], DB[3], DB[4]);
	done = true;
	break;
      case LAN_X_HEADER_CV_WRITE:
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d CV WRITE "), this->clientid);
	notifyFirmwareVersion();
	done = true;
	break;
      case LAN_X_HEADER_SET_TURNOUT:
	// XXX sent when operating a turnout
	if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d SET TURNOUT "), this->clientid);
      case LAN_X_HEADER_READ_REGISTER:
	break;
      }
      break;
      
    case HEADER_LAN_SET_BROADCASTFLAGS:
      this->broadcastFlags = int32_t(Data[3] << 24 | Data[2] << 16 | Data[1] << 8 | Data[0]);
      if (Diag::Z21THROTTLEDATA) DIAG(F("BROADCAST FLAGS %d : %s %s %s %s %s %s %s %s %s %s %s"), this->clientid,
				      (this->broadcastFlags & BROADCAST_BASE)	? "BASE " : "" ,
				      (this->broadcastFlags & BROADCAST_RBUS)	? "RBUS " : "" ,
				      (this->broadcastFlags & BROADCAST_RAILCOM)	? "RAILCOM " : "" ,
				      (this->broadcastFlags & BROADCAST_SYSTEM)	? "SYSTEM " : "" ,
				      (this->broadcastFlags & BROADCAST_BASE_LOCOINFO)	? "LOCOINFO " : "" ,
				      (this->broadcastFlags & BROADCAST_LOCONET)	? "LOCONET " : "" ,
				      (this->broadcastFlags & BROADCAST_LOCONET_LOCO)	? "LOCONET_LOCO " : "" ,
				      (this->broadcastFlags & BROADCAST_LOCONET_SWITCH)	? "LOCONET_SWITCH " : "" ,
				      (this->broadcastFlags & BROADCAST_LOCONET_DETECTOR)	? "LOCONET_DETECTOR " : "" ,
				      (this->broadcastFlags & BROADCAST_RAILCOM_AUTO)	? "RAILCOM_AUTO " : "" ,
				      (this->broadcastFlags & BROADCAST_CAN)	? "CAN" : "" );
      done = true;
      break;
    case HEADER_LAN_GET_LOCOMODE:
      if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d GET LOCOMODE"), this->clientid);
      notifyLocoMode(Data[0], Data[1]);	// big endian here, but resend the same as received, so no problem.
      done = true;
      break;
      
    case HEADER_LAN_SET_LOCOMODE:
      if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d SET LOCOMODE"), this->clientid);
      done = true;
      break;
    case HEADER_LAN_GET_HWINFO:
      if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d GET HWINFO"), this->clientid);
      notifyHWInfo();	// big endian here, but resend the same as received, so no problem.
      done = true;
      break;
    case HEADER_LAN_LOGOFF:
      if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d LOGOFF"), this->clientid);
      this->clientid = -1;
      done = true;
      break;
    case HEADER_LAN_SYSTEMSTATE_GETDATA:
      if (Diag::Z21THROTTLEVERBOSE) DIAG(F("%d SYSTEMSTATE GETDATA"), this->clientid);
      notifyStatus();	// big endian here, but resend the same as received, so no problem.
      done = true;
      break;
    case HEADER_LAN_GET_SERIAL_NUMBER:
      // XXX this has been seen, return dummy number
    case HEADER_LAN_GET_BROADCASTFLAGS:
    case HEADER_LAN_GET_TURNOUTMODE:
    case HEADER_LAN_SET_TURNOUTMODE:
    case HEADER_LAN_RMBUS_DATACHANGED:
    case HEADER_LAN_RMBUS_GETDATA:
    case HEADER_LAN_RMBUS_PROGRAMMODULE:
    case HEADER_LAN_RAILCOM_DATACHANGED:
    case HEADER_LAN_RAILCOM_GETDATA:
    case HEADER_LAN_LOCONET_DISPATCH_ADDR:
    case HEADER_LAN_LOCONET_DETECTOR:
      break;
    }
    
    if (!done) {
      if (Diag::Z21THROTTLE) DIAG(F("Z21 Throttle %d : not treated :  Header:%x   Xheader:%x   DB0:%x"), this->clientid, Header, Xheader, DB[0]);
    } else {
      int newNbLocos = CountLocos();
      if (nbLocos != newNbLocos)
	printLocomotives();
    }
  }
  // if we get here, we did parse one or several xbus packets inside USB packets
  return true;
}