convert method

@override Iterable<bool> convert(String data)

Implementation

@override
Iterable<bool> convert(String data) sync* {
  if (fixedLength != null) {
    data = checkLength(data, fixedLength!);
  } else {
    if (zeroPrepend && ((data.length % 2 != 0) != addChecksum)) {
      data = "0$data";
    }

    if (addChecksum) {
      data += checkSumModulo10(data);
    }

    if (data.length % 2 != 0) {
      throw BarcodeException("$name barcode can only encode an even number of digits.");
    }
  }

  yield* add(BarcodeMaps.itfStart, 4);

  final List<int> cu = data.codeUnits;
  for (int i = 0; i < cu.length / 2; i++) {
    final List<int?> tuple = <int?>[BarcodeMaps.itf[cu[i * 2]], BarcodeMaps.itf[cu[i * 2 + 1]]];

    if (tuple[0] == null || tuple[1] == null) {
      throw BarcodeException('Unable to encode "${String.fromCharCode(cu[i * 2])}${String.fromCharCode(cu[i * 2 + 1])}" to $name Barcode');
    }

    for (int n = 0; n < 10; n++) {
      final int v = (tuple[n % 2]! >> (n ~/ 2)) & 1;
      final bool c = n % 2 == 0;
      yield c;
      if (v != 0) {
        yield c;
        yield c;
      }
    }
  }

  yield* add(BarcodeMaps.itfEnd, 5);
}