Carrier signal receiving simple RF

gistfile1.ino

byte leftSideData[MAX_LEFTSIDE_KEYS]={0};
uint8_t receivingIndex = 0;
boolean receiving = false;

const byte CARRIER=B10101010,PRE=0x5E,ADDR=0x10,NOTHING=0xFE,ERROR=0x77;
int receiveState = CARRIER;

const byte START = 0xD0;
const byte STOP = 0xDF;

static void receiveLeftKeyState(){
  //package begin flag received
  if(!receiving && receivePackage() == START){
    receiving = true;
  }
  if(receiving){
    byte data = receivePackage();
    if(data != NOTHING &&
      data != STOP && 
      data != ERROR && 
      receivingIndex < MAX_LEFTSIDE_KEYS){
      
      leftSideData[receivingIndex]=data;
      receivingIndex++;
    }
    else if(data == STOP || receivingIndex == MAX_LEFTSIDE_KEYS){
      receiving = false;
      stateChanged = true;
        
      integrateLeftKeys();
        
      receivingIndex = 0;
      memset(leftSideData,0x00,MAX_LEFTSIDE_KEYS);
    }
    else if(data == ERROR){
      receiving = false;
      receivingIndex = 0;
      memset(leftSideData,0x00,MAX_LEFTSIDE_KEYS);
    }
  }
}

static byte receivePackage(){
  byte erg = NOTHING;
  //check whole packages available
  if(Serial434.available()){
    if(receiveState == CARRIER){
      byte in = Serial434.read();
      if(in == PRE){ 
        receiveState = PRE; 
      }
    }
    
    if(receiveState == PRE) {
      if(Serial434.available() > 2){
        byte addr = Serial434.read();
        byte data = Serial434.read(); 
        byte chck = Serial434.read();
        
        if(addr == ADDR && addr + data == chck){
          erg = data;
        }
        else{
          erg = ERROR;
        }
        receiveState = CARRIER;
      }
    }
  }
  
  return erg;
}