parseLayerData static method

List<int>? parseLayerData(Parser parser, FileEncoding encoding, Compression? compression)

Implementation

static List<int>? parseLayerData(
  Parser parser,
  FileEncoding encoding,
  Compression? compression,
) {
  final dynamic data = parser.formatSpecificParsing<dynamic>(
    (json) => json.json['data'],
    (xml) {
      if (xml.element.children.length != 1) {
        return null;
      }
      final text = xml.element.children.first;
      if (text is XmlText) {
        return text.text;
      }
      return null;
    },
  );

  if (data == null) {
    return null;
  }

  if (encoding == FileEncoding.csv) {
    if (data is List) {
      return data.cast<int>();
    } else {
      // csv data must be parsed
      return List.from(
        (data as String).split(',').map<int>((s) => int.parse(s.trim())),
      );
    }
  }
  // Ok, its base64
  final trim = data.toString().replaceAll('\n', '').trim();
  final decodedString = base64.decode(trim);
  // zlib, gzip, zstd or empty
  List<int> decompressed;
  switch (compression) {
    case Compression.zlib:
      decompressed = const ZLibDecoder().decodeBytes(decodedString);
      break;
    case Compression.gzip:
      decompressed = GZipDecoder().decodeBytes(decodedString);
      break;
    case Compression.zstd:
      throw UnsupportedError('zstd is an unsupported compression');
    case null:
      decompressed = decodedString;
      break;
  }

  // From the tiled documentation:
  // Now you have an array of bytes, which should be interpreted as an array
  // of unsigned 32-bit integers using little-endian byte ordering.
  final bytes = Uint8List.fromList(decompressed);
  final dv = ByteData.view(bytes.buffer);
  final uint32 = <int>[];
  for (var i = 0; i < decompressed.length; ++i) {
    if (i % 4 == 0) {
      uint32.add(dv.getUint32(i, Endian.little));
    }
  }
  return uint32;
}