Adler-32 Checksum

[MrFuppes]

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…

[MrFuppes]

Hi GerdW,

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

[MrFuppes · Accepted solution]

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…

[MrFuppes]

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

[rcpacini]

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