Mod() function and large numbers

Hi all,

I've searched the newsgroup regarding the subject of my message but haven't found the answer, so I need you're help. Here's the example:

String: 1201000030921111100

I need to convert string this length to integer, and then to use Mod() function:

Mod(1201000030921111100,97)

which using windows calculator returns: 39

The problem occurs when I try to use Val() function - I get the number: 12010000309211111000 - with extra 0 in the end. So, Mod(,97) returns 76 instead 39.

I've seen Frans de Witt CPU Class, but haven't been able to implement it. I would appreciate your's help.

Regards,

Milun Vasilijevic

Milun

> The problem occurs when I try to use Val() function - I get the number:
> 12010000309211111000 - with extra 0 in the end. So, Mod(,97) returns 76
> instead 39.

No idea how you got that - all I get is a numeric overflow error (ie the
text/number is to big for a 32bit value)

If it came from a 64bit system then you'll need 64bit routines to handle it.
VO isn't a 64bit system and more than likely never will be<bg>
You might try using Vulcan to do the conversion, I believe .NET can handle
64bit numerics.

CYA
Steve

On 13/07/2012 02:36, Milun Vasilijevic wrote:
> Hi all,
>
> I've searched the newsgroup regarding the subject of my message but haven't found the answer, so I need you're help. Here's the example:
>
> String: 1201000030921111100
>
> I need to convert string this length to integer, and then to use Mod() function:

First of all, as noted, that number is too large to fit into a VO integer
(largest value in a 32 bit signed integer 2147483648==2^32-1)

You are even running close to the limit of 64 bit integers
1201000030921111100 your number
9223372036854775807==2^63-1

which strongly suggests that the 64 bit float that is used by val cannot
be exact (I think an IEEE 64 bit real8 has about 48 bits of accurancy?
), which means it is meaningless to use mod

> Mod(1201000030921111100,97)
>
> which using windows calculator returns: 39
>
> The problem occurs when I try to use Val() function - I get the number: 12010000309211111000 -
with extra 0 in the end. So, Mod(,97) returns 76 instead 39.

yes - this is the expected result because there is no datatype in VO
that can exactly store that number.

probably the most important question is whether a 64 bit int would be
enough or whether you have to use arbitrary precision classes instead.

On 13/07/2012 09:38, Malcolm G wrote:
> On 13/07/2012 02:36, Milun Vasilijevic wrote:
>> Hi all,
>>
>> I've searched the newsgroup regarding the subject of my message but haven't found the answer, so I need you're help. Here's the example:
>>
>> String: 1201000030921111100
>>
>> I need to convert string this length to integer, and then to use Mod() function:

As someone else has pointed out you may well be using IBANS.

If you are specifically doing that, this code may be some help,
no warrently but I assume you can see why it works.


static function Remainder97 (cCheck as string) as int
local retval as int
IF LEN (cCheck) < 9
retval := VAL (cCheck)
retval := retval % 97
ELSE
retval := Remainder97 (TrimStr (Remainder97 (Left (cCheck, 8))) +
Substr (cCheck, 9))
ENDIF
return retval

Delete all lines with Log2DB(...)
This was only for test.

Norbert

Hi Norbert,

Great Function, in Portugal the 21 digits on the right are the NIB, any idea to validate only these digits?

all suggestions are welcome.

TIA
Paulo Oliveira

Hi Paolo,

> Great Function, in Portugal the 21 digits on the right are the NIB,
any idea to validate only these digits?

Sorry NO.

But a really good function is Remainder97 from Malcolm - Congratulation.
Best will be to combine these 2 functions.

Norbert

I can also offer some IBAN Check code using the arithmetic of an Oracle
database.

Arne Ortlinghaus
ACS Data Systems


method ValidateIBAN(cIBANChar as string) class clsIBAN
local cIBANTmp1, cIBANTmp2, cChar, cSql as string
local iPos as dword
local nChDig as usual

if ascan(_aLaender,left(cIBANChar,2)) == 0
return true
end if
cIBANChar := AllTrim(cIBANChar) // Todo 66425 AO 12.07.2012 Runtimefehler
bei IBAN-Prüfung im Falle von falschen Zeichen
cIBANTmp1 := substr(cIBANChar,5)+left(cIBANChar,4)
cIBANTmp2 := ""

for iPos := 1 to slen(cIBANTmp1)
cChar := substr(cIBANTmp1,iPos,1)
if ! isdigit(string2psz(cChar))
cChar := str(asc(cChar)-55,2)
end if
cIBANTmp2 += cChar
next
if !Empty(Val(cIBANTmp2)) // Todo 63367 Fehlermeldung bei Import IBAN in
Kunden/Lieferanten
cSql := 'SELECT MOD('+SQLValue2SQLString(cIBANTmp2)+',97) "Modulus" FROM
DUAL'
nChDig := GetSQLValueFast(cSql, "N", 10, 0, 0, null_object, true)
else
nChDig := 0
endif
//msginfo(cIBANChar+chr(13)+chr(10)+cIBANTmp1+chr(13 )+chr(10)+cIBANTmp2+chr(13)+chr(10)+cSql+chr(13)+c hr(10)+typevalue2string(nChDig))

return nChDig == 1
method Init(oOwner, oServer) class clsIBAN

_oOwner := oOwner
_oServer := oServer

_aLaender := ArrayCreate(18)
_aLaengen := ArrayCreate(18)

_aLaender[1] := "IT"
_aLaengen[1] := 27
_aLaender[2] := "AT"
_aLaengen[2] := 20
_aLaender[3] := "BE"
_aLaengen[3] := 16
_aLaender[4] := "CH"
_aLaengen[4] := 21
_aLaender[5] := "DE"
_aLaengen[5] := 22
_aLaender[6] := "DK"
_aLaengen[6] := 18
_aLaender[7] := "ES"
_aLaengen[7] := 24
_aLaender[8] := "FI"
_aLaengen[8] := 18
_aLaender[9] := "FR"
_aLaengen[9] := 27
_aLaender[10] := "GB"
_aLaengen[10] := 22
_aLaender[11] := "IE"
_aLaengen[11] := 22
_aLaender[12] := "IS"
_aLaengen[13] := 26
_aLaender[13] := "LU"
_aLaengen[13] := 20
_aLaender[14] := "NL"
_aLaengen[14] := 18
_aLaender[15] := "NO"
_aLaengen[15] := 15
_aLaender[16] := "PT"
_aLaengen[16] := 25
_aLaender[17] := "SE"
_aLaengen[17] := 24
_aLaender[18] := "SM"
_aLaengen[18] := 27
return self
class clsIBAN

protect _oOwner as object
protect _oServer as object
protect _aLaender as array
protect _aLaengen as array

declare method ValidateIBAN

Hi Norbert, Malcom, and everybody who came to the rescue,

Thank you for your time, you've been very helpful. In the end I implementedMalcom's great function Remainder97.

You were right - I needed this function for digit checking in my e-banking payment order module. It wasn't IBAN numbers but rather similar thing: adding control number to the reference number of payment order.

Once again thank you very much.

Milun Vasilijevic


петак, 13. јул 2012. 16.59.10 UTC+2, Norbert Kolb је напи�ао/ла:
> Hi Paolo,
>
> &gt; Great Function, in Portugal the 21 digits on the right are the NIB,
> any idea to validate only these digits?
>
> Sorry NO.
>
> But a really good function is Remainder97 from Malcolm - Congratulation.
> Best will be to combine these 2 functions.
>
> Norbert

One more thing. It was ISO 7064 Mod 97,10 standard I had to implement:

http://code.google.com/p/checkdigits...ckDigitSystems

Milun