public int Checksum(IbanDigitizer digitizer)
{
var digits = 0;
var n = 0;
int d;
while (digitizer.MoveNext())
{
// We need to read until we have a nine
// digit number. Since it can start with zero
// it's not possible to use Math.Log10().
var integer = digitizer.Current;
if (++digits < 9)
{
n = 10 * (n + integer);
continue;
}
n += integer;
d = n % 97;
n = 10 * d;
digits = d > 10 ? 2 : 1;
}
// Last digit is base 10^0 so "divide it away"
d = n / 10 % 97;
return(d); // == 1;
}
public bool SpaceEfficient()
{
var digitizer = new IbanDigitizer(Iban);
return(_calculator.Checksum(digitizer) == 1);
//var verifier = new IbanChecksumVerifier(Iban);
//return verifier.VerifyChecksum();
}
public void VerifyChecksum(string iban)
{
// Arrange
var digitizer = new IbanDigitizer(iban);
// Act
var checksum = _calculator.Checksum(digitizer);
// Assert
Assert.True(checksum == 1);
}
