gnssview_old/plugins/gnss/lib/nmea/sentence.dart

// ignore_for_file: constant_identifier_names

import 'dart:core';
import 'dart:developer';

import 'tagblock.dart';

// TagBlockSep is the separator (slash `\`) that indicates start and end of tag block
const TagBlockSep = '\\';

// SentenceStart is the token to indicate the start of a sentence.
const SentenceStart = "\$";

// SentenceStartEncapsulated is the token to indicate the start of encapsulated data.
const SentenceStartEncapsulated = "!";

// ProprietarySentencePrefix is the token to indicate the start of parametric sentences.
const ProprietarySentencePrefix = 'P';

// QuerySentencePostfix is the suffix token to indicate the Query sentences.
const QuerySentencePostfix = 'Q';

// FieldSep is the token to delimit fields of a sentence.
const FieldSep = ",";

// ChecksumSep is the token to delimit the checksum of a sentence.
const ChecksumSep = "*";

// Define the interface for all NMEA sentences
abstract class Sentence {
  String prefix();
  String dataType();
  String talkerID();
}

// Define the structure for the NMEA sentence
class BaseSentence implements Sentence {
  String talker; // The talker id (e.g GP)
  String type; // The data type (e.g GSA)
  List<String> fields; // Array of fields
  int checksum; // The (raw) Checksum
  String raw; // The raw NMEA sentence received
  TagBlock tagBlock; // NMEA tagblock

  BaseSentence(this.talker, this.type, this.fields, this.checksum, this.raw,
      this.tagBlock);

  @override
  String prefix() {
    return talker + type;
  }

  @override
  String dataType() {
    return type;
  }

  @override
  String talkerID() {
    return talker;
  }

  String string() {
    return raw;
  }
}

// Define the callback type used to parse specific sentence variants
typedef ParserFunc = BaseSentence Function(BaseSentence s);

// Define the error returned when a parsed sentence is not supported
class NotSupportedError {
  String prefix;

  NotSupportedError(this.prefix);

  @override
  String toString() {
    return 'nmea: sentence prefix \'$prefix\' not supported';
  }
}

const List<int> aulCrcTable = [
  0x00000000,
  0x77073096,
  0xee0e612c,
  0x990951ba,
  0x076dc419,
  0x706af48f,
  0xe963a535,
  0x9e6495a3,
  0x0edb8832,
  0x79dcb8a4,
  0xe0d5e91e,
  0x97d2d988,
  0x09b64c2b,
  0x7eb17cbd,
  0xe7b82d07,
  0x90bf1d91,
  0x1db71064,
  0x6ab020f2,
  0xf3b97148,
  0x84be41de,
  0x1adad47d,
  0x6ddde4eb,
  0xf4d4b551,
  0x83d385c7,
  0x136c9856,
  0x646ba8c0,
  0xfd62f97a,
  0x8a65c9ec,
  0x14015c4f,
  0x63066cd9,
  0xfa0f3d63,
  0x8d080df5,
  0x3b6e20c8,
  0x4c69105e,
  0xd56041e4,
  0xa2677172,
  0x3c03e4d1,
  0x4b04d447,
  0xd20d85fd,
  0xa50ab56b,
  0x35b5a8fa,
  0x42b2986c,
  0xdbbbc9d6,
  0xacbcf940,
  0x32d86ce3,
  0x45df5c75,
  0xdcd60dcf,
  0xabd13d59,
  0x26d930ac,
  0x51de003a,
  0xc8d75180,
  0xbfd06116,
  0x21b4f4b5,
  0x56b3c423,
  0xcfba9599,
  0xb8bda50f,
  0x2802b89e,
  0x5f058808,
  0xc60cd9b2,
  0xb10be924,
  0x2f6f7c87,
  0x58684c11,
  0xc1611dab,
  0xb6662d3d,
  0x76dc4190,
  0x01db7106,
  0x98d220bc,
  0xefd5102a,
  0x71b18589,
  0x06b6b51f,
  0x9fbfe4a5,
  0xe8b8d433,
  0x7807c9a2,
  0x0f00f934,
  0x9609a88e,
  0xe10e9818,
  0x7f6a0dbb,
  0x086d3d2d,
  0x91646c97,
  0xe6635c01,
  0x6b6b51f4,
  0x1c6c6162,
  0x856530d8,
  0xf262004e,
  0x6c0695ed,
  0x1b01a57b,
  0x8208f4c1,
  0xf50fc457,
  0x65b0d9c6,
  0x12b7e950,
  0x8bbeb8ea,
  0xfcb9887c,
  0x62dd1ddf,
  0x15da2d49,
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  0xfbd44c65,
  0x4db26158,
  0x3ab551ce,
  0xa3bc0074,
  0xd4bb30e2,
  0x4adfa541,
  0x3dd895d7,
  0xa4d1c46d,
  0xd3d6f4fb,
  0x4369e96a,
  0x346ed9fc,
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  0xda60b8d0,
  0x44042d73,
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  0xaa0a4c5f,
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  0x5005713c,
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  0xb966d409,
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  0x5edef90e,
  0x29d9c998,
  0xb0d09822,
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  0xa1d1937e,
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  0x4fdff252,
  0xd1bb67f1,
  0xa6bc5767,
  0x3fb506dd,
  0x48b2364b,
  0xd80d2bda,
  0xaf0a1b4c,
  0x36034af6,
  0x41047a60,
  0xdf60efc3,
  0xa867df55,
  0x316e8eef,
  0x4669be79,
  0xcb61b38c,
  0xbc66831a,
  0x256fd2a0,
  0x5268e236,
  0xcc0c7795,
  0xbb0b4703,
  0x220216b9,
  0x5505262f,
  0xc5ba3bbe,
  0xb2bd0b28,
  0x2bb45a92,
  0x5cb36a04,
  0xc2d7ffa7,
  0xb5d0cf31,
  0x2cd99e8b,
  0x5bdeae1d,
  0x9b64c2b0,
  0xec63f226,
  0x756aa39c,
  0x026d930a,
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  0xd70dd2ee,
  0x4e048354,
  0x3903b3c2,
  0xa7672661,
  0xd06016f7,
  0x4969474d,
  0x3e6e77db,
  0xaed16a4a,
  0xd9d65adc,
  0x40df0b66,
  0x37d83bf0,
  0xa9bcae53,
  0xdebb9ec5,
  0x47b2cf7f,
  0x30b5ffe9,
  0xbdbdf21c,
  0xcabac28a,
  0x53b39330,
  0x24b4a3a6,
  0xbad03605,
  0xcdd70693,
  0x54de5729,
  0x23d967bf,
  0xb3667a2e,
  0xc4614ab8,
  0x5d681b02,
  0x2a6f2b94,
  0xb40bbe37,
  0xc30c8ea1,
  0x5a05df1b,
  0x2d02ef8d
];

class SentenceParser {
  Map<String, ParserFunc> customParsers;
  Function(String)? parsePrefix;
  Function(BaseSentence, String)? checkCRC;
  Function(TagBlock)? onTagBlock;

  SentenceParser(
      this.customParsers, this.parsePrefix, this.checkCRC, this.onTagBlock);

  BaseSentence parseBaseSentence(String raw) {
    // raw = raw.trim();
    if (raw.isEmpty) {
      throw ArgumentError('nmea: can not parse empty input');
    }

    TagBlock tagBlock = TagBlock(0, 0, "", "", 0, "", "");
    var startIndex = raw.indexOf(RegExp(r'\$|!|#'));
    if (startIndex != 0) {
      raw;
      log("NMEA sentence does not start with a '\$' or '!' or '#'");
    }

    var checksumSepIndex = raw.indexOf('*');
    var rawFields = raw.substring(
        startIndex + 1, checksumSepIndex != -1 ? checksumSepIndex : raw.length);
    var checksumRaw = -1;
    if (checksumSepIndex != -1) {
      rawFields = raw.substring(startIndex + 1, checksumSepIndex);
      checksumRaw = int.parse(raw.substring(checksumSepIndex + 1), radix: 16);
    }
    List<String> fields = rawFields.split(',');

    String talkerID;
    String type;
    List<String> result;
    if (parsePrefix != null) {
      result = parsePrefix!(fields[0]);
    } else {
      result = _parsePrefix(fields[0]);
    }

    talkerID = result[0];
    type = result[1];
    var sentence = BaseSentence(
        talkerID, type, fields.sublist(1), checksumRaw, raw, tagBlock);
    if (checkCRC != null) {
      checkCRC!(sentence, rawFields);
    } else {
      int checksum;
      if (raw[0] == "#") {
        //#HEADING,#BESTPOSA
        checksum = _calculateCRC32(rawFields);
      } else {
        checksum = _calculateChecksum(rawFields);
      }
      if (checksum != sentence.checksum) {
        throw ArgumentError(
            'nmea: sentence checksum mismatch [$checksum != ${sentence.checksum}]');
      }
    }
    return sentence;
  }

  int _calculateChecksum(String s) {
    var checksum = 0;
    for (var i = 0; i < s.length; i++) {
      checksum ^= s.codeUnitAt(i);
    }
    return checksum;
  }

// Calculate and return the CRC for String
  int _calculateCRC32(String str) {
    int crc = 0;
    for (int i = 0; i < str.length; i++) {
      crc = (aulCrcTable[(crc ^ str.codeUnitAt(i)) & 0xff] ^ (crc >> 8));
    }
    return crc;
  }

  List<String> _parsePrefix(String prefix) {
    if (prefix.isEmpty) {
      log('nmea: sentence prefix is empty');
      // throw ArgumentError('nmea: sentence prefix is empty');
      return ['', prefix];
    }
    if (prefix[0] == 'P') {
      return ['P', prefix.substring(1)];
    }
    if (prefix.length == 5) {
      if (prefix[4] == 'Q') {
        return [prefix.substring(0, 2), 'Q'];
      }
      return [prefix.substring(0, 2), prefix.substring(2)];
    }
    return ['', prefix];
  }

  BaseSentence parse(String raw) {
    var s = parseBaseSentence(raw);
    if (customParsers.containsKey(s.type)) {
      return customParsers[s.type]!(s);
    }
    return s;
  }
}