start adding MQTT client channel implementation

DccMQTT.cpp

@@ -50,7 +50,29 @@ char topicName[MAXTBUF];
 char topicMessage[MAXTMSG];
 // char keyword[MAX_KEYWORD_LENGTH];
 
+// pairing functions used for creating a client identifier
+// when a external system connects via MQ to the CS i.e. subscribes to the main channel the first message to be published
+// shall be a admin message with a random number
+// the cs will based on a counter use a second number to create the cantor encoding of both numbers and publish the cantor code
+// this message will be seen by all throttles and they can decode the number which provides the first number they send and the
+// second number  to be used as tpoic for the external system from then on. The CS will recieve on all topics the commands and
+// during processing then send the replies to the topic from which the command was recieved.
+// Thus the main channel shall not be used for any p2p coms ev just for broadcast from the CS to the subscribed clients
 
+int cantorEncode(int a, int b)
+{
+
+  return (((a + b) * (a + b + 1)) / 2) + b;
+}
+
+void cantorDecode(int c, int *a, int *b)
+{
+
+  int w = floor((sqrt(8 * c + 1) - 1) / 2);
+  int t = (w * (w + 1)) / 2;
+  *b = c - t;
+  *a = w - *b;
+}
 
 /**
  * @brief Copies an byte array to a hex representation as string; used for generating the unique Arduino ID
@@ -78,6 +100,11 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
   topicMessage[0] = '\0';
   strcpy(topicName, topic);
 
+  switch (payload[0])
+  {
+  case '<':
+  {
+    // DCC-EX command
     auto pool = mqtt->getPool();
     auto q = mqtt->getIncomming();
 
@@ -85,13 +112,31 @@ void mqttCallback(char *topic, byte *payload, unsigned int length)
     strlcpy(tm.cmd, (char *)payload, length + 1);
     // Add the recieved command to the pool
     int idx = pool->setItem(tm);
-  if ( idx == -1) {
+    if (idx == -1)
+    {
       DIAG(F("MQTT Command pool full. Could not handle recieved command."));
       return;
     }
     // Add the index of the pool item to the incomming queue
     q->push(idx);
     DIAG(F("MQTT Message arrived [%s]: [%s]"), topicName, tm.cmd);
+    break;
+  }
+  case '(':
+  {
+    // MQTT Ctrl command
+    payload[length] = '\0';
+    DIAG(F("MQTT Ctrl Message arrived [%s]: [%s]"), topicName, (char *)payload);
+    break;
+  }
+  default:
+  {
+    // invalid command
+    payload[length] = '\0';
+    DIAG(F("MQTT Invalid DCC-EX command: %s"), (char *)payload);
+    break;
+  }
+  }
 }
 
 /**
@@ -106,7 +151,8 @@ void DccMQTT::connect()
 
   int reconnectCount = 0;
 
-  if(broker->prefix != nullptr) {
+  if (broker->prefix != nullptr)
+  {
     char tmp[20];
     strcpy_P(tmp, (const char *)broker->prefix);
     connectID[0] = '\0';
@@ -162,7 +208,8 @@ while (!mqttClient.connected() && reconnectCount < MAXRECONNECT)
 
 // for the time being only one topic at the root which os the unique clientID from the MCU
 // QoS is 0 by default
-boolean DccMQTT::subscribe() {
+boolean DccMQTT::subscribe()
+{
   return mqttClient.subscribe(clientID);
 }
 
@@ -228,12 +275,9 @@ void DccMQTT::setup(const FSH *id, MQTTBroker *b)
   // mqttDccExParser = p;
 }
 
-
 void DccMQTT::loop()
 {
 
-  // DccTelemetry::deltaT(1);
-
   if (!mqttClient.connected())
   {
     connect();
@@ -242,9 +286,30 @@ void DccMQTT::loop()
   {
     DIAG(F("mqttClient returned with error; state: %d"), mqttClient.state());
   };
+
+  // read incomming queue for processing; one per loop
+  bool state;
+  if (in.count() > 0)
+  {
+    auto idx = in.peek();
+    auto c = pool.getItem(in.pop(), &state);
+    DIAG(F("MQTT Processing pool: %d with command: %s"), idx, c->cmd);
+  }
+
+  // read outgoing queue for publishing replies; one per loop
+  if (out.count() > 0)
+  {
+    auto m = pool.getItem(out.pop(), &state);
+    DIAG(F("MQTT Publish reply from command %s"), m->cmd);
+  }
+
   // DccMQTTProc::loop(); //!< give time to the command processor to handle msg ..
+  // take a command from the incomming queue
+  // execute it
+  // store the results in the outgoing queue
+
   // DccMQTT::publish();  //!< publish waiting messages from the outgoing queue
-  // DccTelemetry::deltaT(1);
+  // if there is someting in the outgoing queue publish on response
 }
 
 // #include <avr/pgmspace.h> // for PROGMEM use

DccMQTT.h

@@ -22,9 +22,10 @@
 #define MAXTBUF 50  //!< max length of the buffer for building the topic name ;to be checked
 #define MAXTMSG 120 //!< max length of the messages for a topic               ;to be checked PROGMEM ?
 #define MAXTSTR 30  //!< max length of a topic string
-#define MAXCONNECTID 40
+#define MAXCONNECTID 40             // Broker connection id length incl possible prefixes
-#define CLIENTIDSIZE 6
+#define CLIENTIDSIZE 6              //  
-#define MAXRECONNECT 5
+#define MAXRECONNECT 5              // reconnection tries before final failure
+#define MAXMQTTCONNECTIONS 20       // maximum number of unique tpoics available for subscribers
 
 // Define Broker configurations; Values are provided in the following order
 // MQTT_BROKER_PORT 9883
@@ -79,10 +80,20 @@ struct MQTTBroker
     };
 };
 
+/**
+ * @brief dcc-ex command as recieved via MQ
+ * 
+ */
 typedef struct csmsg_t { 
 	char cmd[MAXPAYLOAD]; 
 } csmsg_t; 
 
+typedef struct csmqttclient_t {
+    uint8_t subscriber;
+    uint8_t cs;
+
+} csmqttclient_t
+
 enum DccMQTTState
 {
     INIT,
@@ -101,6 +112,8 @@ private:
     void setup(const FSH *id, MQTTBroker *broker);
     void connect();                 // (re)connects to the broker 
     boolean subscribe();      
+    // static int cantorEncode(int a, int b);
+    // static void cantorDecode(int c, int *a, int *b);     
 
     EthernetClient  ethClient;      // TCP Client object for the MQ Connection
     IPAddress       server;         // MQTT server object
@@ -115,6 +128,9 @@ private:
 
     DccMQTTState mqState = INIT;
 
+    
+
+
 public:
     static DccMQTT *get() noexcept
     {

DccMQTTProc.cpp

@@ -0,0 +1,16 @@
+/**
+ * @file DccMQTTProc.cpp
+ * @author Gregor Baues (gr2bba@gmail.com)
+ * @brief Eexecuting DCC commands recieved through MQTT.
+ * @version 0.1
+ * @date 08-07-2020
+ * 
+ * @copyright Copyright (c) 2021
+ * 
+ * Licenced under GPLv3
+ */
+
+#include <Arduino.h>
+#include <Diag.h>
+
+

DccMQTTProc.h

@@ -0,0 +1,15 @@
+#ifndef _DccMQTTProc_h_
+#define _DccMQTTProc_h_
+
+class DccMQTTProc
+{
+private:
+    
+public:
+    static void loop();
+
+    DccMQTTProc() = default;
+    ~DccMQTTProc() = default;
+};
+
+#endif