generateBarcodeCheckSum property

Implementation

String get generateBarcodeCheckSum {
  if (isNotNumber) {
    throw const FormatException('Code is not a number');
  }

  int i = 0;
  int j;
  int p = 0;
  int t = length;
  for (j = 1; j <= t; j++) {
    if ((j & ~ -2) == 0) {
      p += int.parse(substring(j - 1, j));
    } else {
      i += int.parse(substring(j - 1, j));
    }
  }

  if (t == 7 || t == 11) {
    i = i * 3 + p;
    p = (i + 9) ~/ 10 * 10;
    t = p - i;
  } else {
    p = p * 3 + i;
    i = (p + 9) ~/ 10 * 10;
    t = i - p;
  }

  return t.toString();
}