server: Z21 Use helper functions in ClientKernel

Use helper functions for LanXSetLocoDrive message

server/src/hardware/protocol/z21/clientkernel.cpp

@@ -333,49 +333,21 @@ void ClientKernel::decoderChanged(const Decoder& decoder, DecoderChangeFlags cha
   {
     LanXSetLocoDrive cmd;
     cmd.setAddress(decoder.address, decoder.protocol == DecoderProtocol::DCCLong);
+    cmd.setDirection(decoder.direction);
 
-    switch(decoder.speedSteps)
+    // Decoder max speed steps must be set for the message to be correctly
+    // distinguished from LAN_X_SET_LOCO_FUNCTION
+    cmd.setSpeedSteps(decoder.speedSteps);
+
+    if(decoder.emergencyStop)
     {
-      case 14:
-      {
-        const uint8_t speedStep = Decoder::throttleToSpeedStep<uint8_t>(decoder.throttle, 14);
-        cmd.db0 = 0x10;
-        if(decoder.emergencyStop)
-          cmd.speedAndDirection = 0x01;
-        else if(speedStep > 0)
-          cmd.speedAndDirection = speedStep + 1;
-        break;
-      }
-      case 28:
-      {
-        uint8_t speedStep = Decoder::throttleToSpeedStep<uint8_t>(decoder.throttle, 28);
-        cmd.db0 = 0x12;
-        if(decoder.emergencyStop)
-          cmd.speedAndDirection = 0x01;
-        else if(speedStep > 0)
-        {
-          speedStep++;
-          cmd.speedAndDirection = ((speedStep & 0x01) << 4) | (speedStep >> 1);
-        }
-        break;
-      }
-      case 126:
-      case 128:
-      default:
-      {
-        const uint8_t speedStep = Decoder::throttleToSpeedStep<uint8_t>(decoder.throttle, 126);
-        cmd.db0 = 0x13;
-        if(decoder.emergencyStop)
-          cmd.speedAndDirection = 0x01;
-        else if(speedStep > 0)
-          cmd.speedAndDirection = speedStep + 1;
-        break;
-      }
+        cmd.setEmergencyStop();
+    }
+    else
+    {
+      const uint8_t speedStep = Decoder::throttleToSpeedStep<uint8_t>(decoder.throttle, cmd.speedSteps());
+      cmd.setSpeedStep(speedStep);
     }
-
-    assert(decoder.direction.value() != Direction::Unknown);
-    if(decoder.direction.value() == Direction::Forward)
-      cmd.speedAndDirection |= 0x80;
 
     cmd.checksum = XpressNet::calcChecksum(*reinterpret_cast<const XpressNet::Message*>(&cmd.xheader));
     postSend(cmd);

server/src/hardware/protocol/z21/messages.hpp

@@ -546,6 +546,24 @@ struct LanXSetLocoDrive : LanX
     addressLow = longAddress ? address & 0xFF : address & 0x7F;
   }
 
+  inline void setSpeedSteps(uint8_t steps)
+  {
+    switch(steps)
+    {
+    case 14:
+      db0 = 0x10;
+      break;
+    case 28:
+      db0 = 0x12;
+      break;
+    case 126:
+    case 128:
+    default:
+      db0 = 0x13;
+      break;
+    }
+  }
+
   inline uint8_t speedSteps() const
   {
     switch(db0 & 0x0F)