Use PacketCRC helper

PacketCRC.cpp

@@ -0,0 +1,51 @@
+#include "PacketCRC.h"
+
+PacketCRC::PacketCRC() : crc(CRC16(0x755B, 0x0, 0xBA68, false, false)) {
+  // Constructor implementation (if needed)
+}
+
+PacketCRC::~PacketCRC() {
+  // Destructor implementation (if needed)
+}
+
+bool PacketCRC::check(const uint8_t* packet) {
+  uint8_t length = packet[1];
+  switch(length) {
+    case 0x11:
+    case 0x15:
+    case 0x19:
+      break;
+    default:
+      return false;
+  }
+
+  uint16_t result = calculate(packet);
+  uint8_t checksum1 = (uint8_t)((result & 0xFF00) >> 8);
+  uint8_t checksum2 = (uint8_t)(result & 0x00FF);
+
+  if (packet[length + 2] == checksum1 && packet[length + 3] == checksum2) {
+    return true;
+  }
+
+  return false;
+}
+
+uint16_t PacketCRC::calculate(const uint8_t* packet) {
+  crc.restart();
+  uint8_t length = packet[1];
+  switch(length) {
+    case 0x11:
+      crc.setXorOut(0x539E);
+      break;
+    case 0x15:
+      crc.setXorOut(0x3B0E);
+      break;
+    case 0x19:
+      crc.setXorOut(0x5C02);
+      break;
+    default:
+      return 0x0000;
+  }
+  crc.add(packet, length + 2);
+  return crc.calc();
+}