checkDigit method
Computes the check digit from data
.
Implementation
@override
int checkDigit(String data) {
if (data.length != 9) {
throw ArgumentError('Must not be null and must contain 9 digits');
}
final sum1 = _compute(data, 10);
final r1 = sum1 % 11;
final v1 = r1 == 0 || r1 == 1 ? 0 : (11 - r1);
final sum2 = _compute(data, 11) + v1 * 2;
final r2 = sum2 % 11;
final v2 = r2 == 0 || r2 == 1 ? 0 : (11 - r2);
return v1 * 10 + v2;
}