server: Z21 add LanXExtAccessoryInfo message

- Support querying and obtaining DCCExt accessory status

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

@@ -89,6 +89,21 @@ void ClientKernel::receive(const Message& message)
           }
           break;
 
+        case LAN_X_EXT_ACCESSORY_INFO:
+          if(message.dataLen() == sizeof(LanXExtAccessoryInfo))
+          {
+            const auto& reply = static_cast<const LanXExtAccessoryInfo&>(message);
+            if(reply.isDataValid())
+            {
+              EventLoop::call(
+                [this, address=reply.address(), value=reply.aspect()]()
+                {
+                  m_outputController->updateOutputValue(OutputChannel::DCCext, address, value);
+                });
+            }
+          }
+          break;
+
         case LAN_X_BC:
           if(message == LanXBCTrackPowerOff() || message == LanXBCTrackShortCircuit())
           {

server/src/hardware/protocol/z21/iohandler/simulationiohandler.cpp

@@ -151,6 +151,29 @@ bool SimulationIOHandler::send(const Message& message)
           }
           break;
         }
+        case LAN_X_SET_EXT_ACCESSORY:
+        {
+          if(message.dataLen() == sizeof(LanXSetExtAccessory))
+          {
+            const auto& setAccessory = static_cast<const LanXSetExtAccessory&>(message);
+            if((m_broadcastFlags & BroadcastFlags::PowerLocoTurnoutChanges) == BroadcastFlags::PowerLocoTurnoutChanges)
+            {
+              // Client has subscribed to turnout changes
+              reply(LanXExtAccessoryInfo(setAccessory.address(), setAccessory.aspect(), false));
+            }
+          }
+          break;
+        }
+        case LAN_X_EXT_ACCESSORY_INFO:
+        {
+          if(message.dataLen() == sizeof(LanXGetExtAccessoryInfo))
+          {
+            const auto& getAccessory = static_cast<const LanXGetExtAccessoryInfo&>(message);
+            //We do not keep a record of accessory states so send "Unknown Position"
+            reply(LanXExtAccessoryInfo(getAccessory.address(), 0, true));
+          }
+          break;
+        }
       }
       break;
     }

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

@@ -120,6 +120,24 @@ std::string toString(const Message& message, bool raw)
           s.append(" queue=").append(setTurnout.queue() ? "yes" : "no");
           break;
         }
+        case LAN_X_EXT_ACCESSORY_INFO:
+        {
+          if(message.dataLen() == sizeof(LanXExtAccessoryInfo))
+          {
+            const auto& reply = static_cast<const LanXExtAccessoryInfo&>(message);
+            s = "LAN_X_EXT_ACCESSORY_INFO";
+            s.append(" address=").append(std::to_string(reply.address()));
+            s.append(" aspect=").append(std::to_string(reply.aspect()));
+            s.append(" unknown=").append(std::to_string(!reply.isDataValid()));
+          }
+          else
+          {
+            const auto& getAccessoryInfo = static_cast<const LanXGetExtAccessoryInfo&>(message);
+            s = "LAN_X_GET_EXT_ACCESSORY_INFO";
+            s.append(" address=").append(std::to_string(getAccessoryInfo.address()));
+          }
+          break;
+        }
         case LAN_X_SET_EXT_ACCESSORY:
         {
           const auto& setExtAccessory = static_cast<const LanXSetExtAccessory&>(message);

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

@@ -145,6 +145,8 @@ enum LocoMode : uint8_t
 
 static constexpr uint8_t LAN_X_TURNOUT_INFO = 0x43;
 static constexpr uint8_t LAN_X_SET_TURNOUT = 0x53;
+
+static constexpr uint8_t LAN_X_EXT_ACCESSORY_INFO = 0x44;
 static constexpr uint8_t LAN_X_SET_EXT_ACCESSORY = 0x54;
 
 static constexpr uint8_t LAN_X_BC = 0x61;
@@ -549,9 +551,109 @@ struct LanXSetExtAccessory : LanX
   {
     return rawAddress() + 3;
   }
+
+  inline uint8_t aspect() const
+  {
+    return db2;
+  }
 } ATTRIBUTE_PACKED;
 static_assert(sizeof(LanXSetExtAccessory) == 10);
 
+// LAN_X_GET_EXT_ACCESSORY_INFO
+struct LanXGetExtAccessoryInfo : LanX
+{
+  uint8_t addressMSB;
+  uint8_t addressLSB;
+  uint8_t db2 = 0x00; // Reserved for future extension, must be 0x00
+  uint8_t checksum;
+
+  LanXGetExtAccessoryInfo(uint16_t address)
+    : LanX(sizeof(LanXGetExtAccessoryInfo), LAN_X_EXT_ACCESSORY_INFO)
+    , addressMSB(high8(address + 3))
+    , addressLSB(low8(address + 3))
+  {
+  }
+
+  inline uint16_t rawAddress() const
+  {
+    return to16(addressLSB, addressMSB);
+  }
+
+  inline uint16_t address() const
+  {
+    return rawAddress() + 3;
+  }
+} ATTRIBUTE_PACKED;
+static_assert(sizeof(LanXGetExtAccessoryInfo) == 9);
+
+// LAN_X_EXT_ACCESSORY_INFO
+struct LanXExtAccessoryInfo : LanX
+{
+  uint8_t addressMSB;
+  uint8_t addressLSB;
+  uint8_t db2;
+  uint8_t db3 = 0x00;
+  uint8_t checksum;
+
+  LanXExtAccessoryInfo(uint16_t address)
+    : LanX(sizeof(LanXExtAccessoryInfo), LAN_X_EXT_ACCESSORY_INFO)
+    , addressMSB(high8(address + 3))
+    , addressLSB(low8(address + 3))
+  {
+  }
+
+  LanXExtAccessoryInfo(uint16_t address, uint8_t aspect, bool isUnknown)
+    : LanXExtAccessoryInfo(address)
+  {
+    db2 = aspect;
+    db3 = isUnknown ? 0xFF : 0x00; // 0xFF represent Unknown Data
+    updateChecksum();
+  }
+
+  LanXExtAccessoryInfo(uint16_t address, bool dir, uint8_t powerOnTime)
+    : LanXExtAccessoryInfo(address)
+  {
+    assert(powerOnTime <= 127);
+    db2 = powerOnTime & 0x7F;
+    if(dir)
+    {
+      db2 |= 0x80;
+    }
+    updateChecksum();
+  }
+
+  inline uint16_t rawAddress() const
+  {
+    return to16(addressLSB, addressMSB);
+  }
+
+  inline uint16_t address() const
+  {
+    return rawAddress() + 3;
+  }
+
+  inline bool isDataValid() const
+  {
+    return db3 == 0x00;
+  }
+
+  inline uint8_t aspect() const
+  {
+    return db2;
+  }
+
+  inline bool direction() const
+  {
+    return db2 & 0x80;
+  }
+
+  inline bool powerOnTime() const
+  {
+    return db2 & 0x7F;
+  }
+} ATTRIBUTE_PACKED;
+static_assert(sizeof(LanXExtAccessoryInfo) == 10);
+
 // LAN_X_SET_STOP
 struct LanXSetStop : LanX
 {