Optimized kiss state machine

kiss_processor.cpp

@@ -3,8 +3,7 @@
 namespace Kiss {
   
 Processor::Processor()
-  : cmd_(Cmd::NoCmd)
-  , state_(State::Void)
+  : state_(State::GetStart)
   , txQueue_(new cppQueue(sizeof(unsigned char), CfgTxQueueSize))
 {
 }
@@ -55,37 +54,34 @@ void Processor::serialProcessRx()
   }
 }
 
-void Processor::resetState()
-{
-  cmd_ = Cmd::NoCmd;
-  state_ = State::Void;
-}
-
 bool Processor::processCommand(byte rxByte) {
 
   switch (rxByte) {
     case Cmd::Data:
-      if (!onRigTxBegin()) return false;
+      if (!onRigTxBegin()) {
+        return false;
+      }
       state_ = State::GetData;
       dataType_ = DataType::Raw;
       break;
+    case Cmd::RadioControl:
+      state_ = State::GetData;
+      dataType_ = DataType::Control;
+      cmdBuffer_.clear();
+      break;
     case Cmd::P:
       state_ = State::GetP;
       break;
     case Cmd::SlotTime:
       state_ = State::GetSlotTime;
       break;
-    case Cmd::RadioControl:
-      state_ = State::GetData;
-      dataType_ = DataType::Control;
-      cmdBuffer_.clear();
+    case Marker::Fend:
       break;
     default:
       // unknown command
-      resetState();
+      state_ = State::GetEnd;
       return true;
   }
-  cmd_ = (Cmd)rxByte;
   return true;
 }
 
@@ -95,23 +91,19 @@ void Processor::processData(byte rxByte) {
       state_ = State::Escape;
       break;
     case Marker::Fend:
-      if (cmd_ == Cmd::Data) {
       if (dataType_ == DataType::Raw) {
         onRigTxEnd();
       } else if (dataType_ == DataType::Control) {
         onRadioControlCommand(cmdBuffer_);
       }
-      }
-      resetState();
+      state_ = State::GetStart;
       break;
     default:
-      if (cmd_ == Cmd::Data) {
       if (dataType_ == DataType::Raw) {
         onRigTx(rxByte);
       } else if (dataType_ == DataType::Control) {
         cmdBuffer_.push_back(rxByte);
       }
-      }
       break;
   }
 }
@@ -119,24 +111,28 @@ void Processor::processData(byte rxByte) {
 bool Processor::receiveByte(byte rxByte) {
 
   switch (state_) {
-    case State::Void:
+    case State::GetStart:
       if (rxByte == Marker::Fend) {
-        cmd_ = Cmd::NoCmd;
         state_ = State::GetCmd;
       }
       break;
+    case State::GetEnd:
+      if (rxByte == Marker::Fend) {
+        state_ = State::GetStart;
+      }
+      break;
     case State::GetCmd:
-      if (rxByte != Marker::Fend) {
-        if (!processCommand(rxByte)) return false;
+      if (!processCommand(rxByte)) {
+        return false;
       }
       break;
     case State::GetP:
       onControlCommand(Cmd::P, rxByte);
-      state_ = State::GetData;
+      state_ = State::GetEnd;
       break;
     case State::GetSlotTime:
       onControlCommand(Cmd::SlotTime, rxByte);
-      state_ = State::GetData;
+      state_ = State::GetEnd;
       break;
     case State::GetData:
       processData(rxByte);
@@ -150,11 +146,13 @@ bool Processor::receiveByte(byte rxByte) {
         onRigTx((byte)Marker::Fesc);
         state_ = State::GetData;
       }
-      else {
-        resetState();
+      else if (rxByte != Marker::Fend) {
+        state_ = State::GetEnd;
       }
       break;
     default:
+      // unknown state
+      state_ = State::GetStart;
       break;
   }
   return true;

kiss_processor.h

@@ -24,7 +24,8 @@ protected:
   };
 
   enum State {
-    Void = 0,
+    GetStart = 0,
+    GetEnd,
     GetCmd,
     GetData,
     GetP,
@@ -72,12 +73,10 @@ private:
   bool receiveByte(byte rxByte);
   void processData(byte rxByte);
   bool processCommand(byte rxByte);
-  void resetState();
 
 private:
-  Cmd cmd_;
-  DataType dataType_;
   State state_;
+  DataType dataType_;
   std::shared_ptr<cppQueue> txQueue_;
   std::vector<byte> cmdBuffer_;
 };