convert method
Implementation
@override
Iterable<bool> convert(String data) sync* {
yield* add(BarcodeMaps.telepenStart, BarcodeMaps.telepenLen);
int checksum = 0;
for (final int code in data.codeUnits) {
if (code >= BarcodeMaps.telepen.length) {
throw BarcodeException('Unable to encode "${String.fromCharCode(code)}" to $name Barcode');
}
final int codeValue = BarcodeMaps.telepen[code];
yield* add(codeValue, BarcodeMaps.telepenLen);
checksum += code;
}
checksum = 127 - (checksum % 127);
if (checksum == 127) {
checksum = 0;
}
yield* add(BarcodeMaps.telepen[checksum], BarcodeMaps.telepenLen);
yield* add(BarcodeMaps.telepenEnd, BarcodeMaps.telepenLen);
}