Adler-32 Checksum

[FObersteiner]

There is a nice .vi for CRC32 (https://forums.ni.com/t5/Example-Code/Calculating-the-CRC32-of-a-File-with-LabVIEW/ta-p/3496230).

Is there something similar for the Adler-32 checksum?

[GerdW]

Hi MrFuppes,

have you tried to implement this yourself?

It seems pretty easy with just 2 shift registers in a loop…

[FObersteiner]

Hi GerdW,

not yet, but will do so I guess if there are no "stock" .vi available...

[FObersteiner]

Here's an implementation:

[GerdW]

Hi MrFuppes,

you see: really easy!

You can delete the ArraySize node, autoindexing at the loop tunnel is all you need…

[FObersteiner]

sure, & thanks. still need to get used to programming in LV 😉

[rcpacini · Accepted solution]

The Adler-32 solution by MrFuppes is incorrect for large data sets.  The high (B, s2) and low (A, s1) should be converted to U32 prior to the add and modulus.

Example:

"abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"

ADLER-32: 0x09832C7D

 

[FObersteiner]

rcpacini,

thank you for reporting this! Kind of a stupid mistake... unfortunately it seems I cannot remove the code I posted. I've marked your answer as 'solution', I hope this helps.

[BertMcMahan]

Go to your post, click the "Options" dropdown, then "Report to a moderator". In that field, explain you'd like to remove the attachment since there's a bug, and they can edit the post for you.