Use PacketCRC helper

HDPacketBuilder.h

@@ -1,4 +1,4 @@
-#include <CRC16.h>
+#include "PacketCRC.h"
 
 #define LENGTH_17                      (0x11)
 #define LENGTH_21                      (0x15)
@@ -15,7 +15,7 @@ uint8_t rollingCode2 = 0x82;
 
 uint8_t buf[32];
 
-CRC16 crc(0x755B, 0x0, 0xBA68, false, false);
+PacketCRC packetCRC;
 
 void setPacketLength(uint8_t);
 void setConstants();
@@ -140,26 +140,9 @@ void setProtocolVersion(uint8_t version) {
 }
 
 void calculateCRC() { // must be called after the buffer has been filled
-  crc.restart();
-  uint8_t length = buf[0];
-  switch(length) {
-    case 0x11:
-      crc.setXorOut(0xBA68);
-      break;
-    case 0x15:
-      crc.setXorOut(0xE10C);
-      break;
-    case 0x19:
-      crc.setXorOut(0x89A0);
-      break;
-    default:
-      Serial.print("Unsupported length (");
-      Serial.print(length);
-      Serial.println("). Cannot calculate CRC");
-      return;
-  }
-  crc.add(buf, length + 1);
-  uint16_t result = crc.calc();
+  uint8_t length = buf[1];
+  uint16_t result = packetCRC.calculate(buf);
+
   uint8_t checksum1 = (uint8_t)((result & 0xFF00) >> 8);
   uint8_t checksum2 = (uint8_t)(result & 0x00FF);