Re: [PATCH] crc: New optimised slice-by-8 implementation

[Sam Russell]

>  `cksum -a crc32` could be added I suppose to select the current implementation in gnulib

both versions are CRC32 though, and then if you look at the iSCSI/SCTP version they use CRC32-C which uses a totally different polynomial, not just a reversed order one like gzip

> I'd be especially reluctant to add the existing cksum crc variant to gnulib,

> since I don't see anything but cksum itself using that.

I need to research a little further, but bzip2 uses the same implementation as cksum afaik

On Thu, 31 Oct 2024 at 18:33, Pádraig Brady <P@draigbrady.com> wrote:

On 31/10/2024 16:46, Sam Russell wrote:
> I can extend coreutils cksum if you like, what are your thoughts on adding some parameters to the commandline? Even if it's just an extra flag for --rfc1952 or --gzip to change all the parameters just between these two variants?

Well cksum already has the -a option to select between algorithms.
`cksum -a crc` currrently select cksums POSIX crc
(which also munges in the data length to the crc calculation).
`cksum -a crc32` could be added I suppose to select the current implementation in gnulib
(and not munge in the length). I can add that easily,
and it probably makes sense to make this more common crc available
(FreeBSD's cksum does for example).

I'd be reluctant to complicate the gnulib implementations with variants unless needed.
I'd be especially reluctant to add the existing cksum crc variant to gnulib,
since I don't see anything but cksum itself using that.

cheers,
Pádraig