[fpc-pascal] old school crc32

[Mark Morgan Lloyd]

wkitty42 at windstream.net wrote:
> On 07/24/2016 05:03 AM, Mark Morgan Lloyd wrote:
>> Have you tried running your test case through a different 
>> implementation? I
>> use http://www.wolfgang-ehrhardt.de/crchash_en.html
> 
> i'm trying to use only what is available in FPC... i will take a look at 
> others, though...

Bug 23472 on Mantis suggests adding that library as a package or whatever.

> [time passes]
> 
> ok, i looked at the one you recommended... the biggest plus is that it 
> had a self-test with a known crc32 for a given string... with that, i 
> was able to figure out what was going on...
> 
> the main thing is that i need the "inverted" crc32... in other words, i 
> needed the bytes all reversed so that i could visually match what i was 
> seeing with what i needed... i didn't realize that swap was only 
> swapping the hi and lo words of the longints... i had to specifically 
> break that down and do it like this...

Same old :-)

I'm using that library (plus at least one other) in a program to drive 
an HP495x protocol analyser, so that it can look at a block of data and 
generate "all known" checksums for investigation.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

[Opinions above are the author's, not those of his employers or colleagues]