CRN/CID Generator

asmilie2b

We need to have NAV print a CID number generated from the document number. This is using algorithm MOD10 V01 or something compatible. I wonder if there are any resources available on doing this purely in C/AL if possible, or perhaps in .NET that anyone has encountered?

asmilie2b

I did find this discussion here:
viewtopic.php?f=23&t=48786&hilit=Luhn+algorithm

However the calculation there was slightly different to what I need for the service I have to comply with, BPay.
Below is the code i came up with. It accepts a string of the CRN to add a checksum, calculates and adds the checksums and then returns it.

GenerateChecksum(CRN : Text) : Text


CLEAR(TotalChars);
CLEAR(TempInteger);

// Find the sum of the multiplied digits
FOR i := STRLEN(CRN) DOWNTO 1 DO BEGIN
  j += 1;
  EVALUATE(TempInteger,COPYSTR(CRN,i,1));
  IF (j MOD 2) <> 0 THEN BEGIN    // Only every 2nd character starting from very right
    CASE TempInteger OF
      1: TempInteger := 2;
      2: TempInteger := 4;
      3: TempInteger := 6;
      4: TempInteger := 8;
      5: TempInteger := 1;
      6: TempInteger := 3;
      7: TempInteger := 5;
      8: TempInteger := 7;
      9: TempInteger := 9;
    END;
  END;
  TotalChars += TempInteger;
END;

// Final calculations
TempInteger := TotalChars MOD 10;
TempInteger := 10 - TempInteger;
CRN := CRN + FORMAT(TempInteger);

EXIT(CRN);