S-RTK GNSS Precision positioning and heading systemS-RTK GNSS｜Precision positioning and heading system

import 'dart:typed_data';
import 'dart:convert';

/**
 * Binary MQTT message parser
 *
 * Parses binary MQTT messages in a specific format.
 */
class MqttBinaryParser {
  // Private constructor prevents instantiation.
  MqttBinaryParser._();

  /// Minimum size of the mqtt_info_t structure in bytes.
  static const int minStructSize = 44; // Minimum required structure size
  static const int fullStructSize = 64; // Full structure size

  /**
   * Parses binary data for the mqtt_info_t structure.
   *
   * @param data Binary data
   * @return A map of parsed data, or null if parsing fails
   */
  static Map<String, dynamic>? parseMqttInfo(Uint8List data) {
    try {
      // Check that the data contains at least the required fields.
      if (data.length < minStructSize) {
        print('MQTT binary parser: expected at least ${minStructSize} bytes; got ${data.length}');
        return null;
      }

      print('Binary MQTT parser: parsing ${data.length} bytes');

      // Create a ByteData view to read different data types.
      final byteData = ByteData.sublistView(data);

      int offset = 0;

      // Parse each field, assuming little-endian byte order.
      final result = <String, dynamic>{};

      // uint32_t devsn - serial number (converted to a hexadecimal string)
      final devsnValue = byteData.getUint32(offset, Endian.little);
      result['devsn'] = devsnValue.toRadixString(16).toUpperCase().padLeft(8, '0');
      offset += 4;

      // uint8_t rev - reserved
      result['rev'] = byteData.getUint8(offset);
      offset += 1;