ValidateMagStripes ( Track1 ; Track2 ; Track3 )

validateMagstripes

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Steven Law - Show more from this author
LSC Media Enterprise

Sample input:

ValidateMagStripes (1234567890 ,;4065893017613664=200422199201073101?
; 0 )

Sample output:

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/*
Validate Magnetic Stripe Tracks

Author: Tim Griffith

Format: ValidateMagStripes ( Track1 ; Track2 ; Track3 )

This will analyze the data intended for encoding onto,
or retrieval from, the tracks of a magnetic stripe on, for
example, a plastic card. It will identify character input 
problems such as invalid ASCII characters per track, 
test for data length per track, and determine if starting
and ending sentinels are correct per track.

The calculated result is three lines of text separated by
carriage returns (so expand your text result field to
view all calculated lines).

When testing for data length I have not taken into account
the LRC, since it is never a part of data encoding, and never
a product of reading the mag stripe (within the sentinels).
*/


Let ( [

TrmTrack1 = Trim ( Track1 ) ;

ClnTrack1 = Filter ( TrmTrack1 ; "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$&'()*?+,-./;:<=>%@[\]_ ^" & "\"" ) ;

TrmTrack2 = Trim ( Track2 ) ;

ClnTrack2 = Filter ( TrmTrack2 ; "0123456789:<>=;?" ) ; 

TrmTrack3 = Trim ( Track3 ) ;

ClnTrack3 = Filter ( TrmTrack3 ; "0123456789:<>=_;?" )


] ;

Case ( Track1 ≠ "" ; 

( Case ( Left ( ClnTrack1 ; 1 ) ≠ "%" ; "This is not Track 1!; " ; "Track 1; " ) & 

Case ( Length ( ClnTrack1 ) < Length ( Track1 ) ; "Invalid characters in Track 1; " ; "Character content 'Valid'; " ) & 

Case ( PatternCount ( ClnTrack1 ; "?" ) < 1 ; "Missing closing sentinel!; " ; "" ) & 

Case ( Length ( ClnTrack1 ) > 78 ; "Data exceeds length limit!" ; "Length is within limits." ) ) ; "Track 1 not available" )

& 

"¶" & 

Case ( Track2 ≠ "" ; 

( Case ( Left ( ClnTrack2 ; 1 ) ≠ ";" ; "This is not Track 2!; " ; "Track 2; " ) & 

Case ( Length ( ClnTrack2 ) < Length ( Track2 ) ; "Invalid characters in Track 2; " ; "Character content 'Valid'; " ) & 

Case ( PatternCount ( ClnTrack2 ; "?" ) < 1 ; "Missing closing sentinel!; " ; "" ) & 

Case ( Length ( ClnTrack2 ) > 39 ; "Data exceeds length limit!" ; "Length is within limits." ) ) ; "Track 2 not available" )

& 
 
"¶" & 

Case ( Track3 ≠ "" ; 

( Case ( Left ( ClnTrack3 ; 2 ) ≠ "_;" ; "This is not Track 3!; " ; "Track 3; " ) & 

Case ( Length ( ClnTrack3 ) < Length ( Track3 ) ; "Invalid characters in Track 3; " ; "Character content 'Valid'; " ) & 

Case ( PatternCount ( ClnTrack3 ; "?" ) < 1 ; "Missing closing sentinel!; " ; "" ) & 

Case ( Length ( ClnTrack3 ) > 106 ; "Data exceeds length limit!" ; "Length is within limits." ) ) ; "Track 3 not available" )

)

This will analyze the data intended for encoding onto,
or retrieval from, the tracks of a magnetic stripe on, for
example, a plastic card. It will identify character input
problems such as invalid ASCII characters per track,
test for data length per track, and determine if starting
and ending sentinels are correct per track.

The calculated result is three lines of text separated by
carriage returns (so expand your text result field to
view all calculated lines).

When testing for data length I have not taken into account
the LRC, since it is never a part of data encoding, and never
a product of reading the mag stripe (within the sentinels).

Comments

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

ValidateMagStripes ( Track1 ; Track2 ; Track3 )

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