Re: [RFC] CryptoAPI & Compression

From: Artem B. Bityuckiy
Date: Sun Apr 03 2005 - 07:03:07 EST




Herbert Xu wrote:
On Sun, Apr 03, 2005 at 03:41:07PM +0400, Artem B. Bityuckiy wrote:

I also wonder, does it at all correct to use negative windowBits in crypto API? I mean, if windowBits is negative, zlib doesn't produce the


It's absolutely correct for IPComp. For other uses it may or may not
be correct.
I've looked through RFC-2394 quickly, but didn't found any mention about non-complient zstreams. I suppose they must be complient by default. Although I'm far not an expert in the area.

For instance for JFFS2 it's absolutely incorrect since it breaks
compatibility. Incidentally, JFFS should create a new compression
type that doesn't include the zlib header so that we don't need the
head-skipping speed hack.
Anyway, in JFFS2 we may do that "hack" before calling pcompress(), so it isn't big problem.

Yes, I'd love to see a patch that makes windowBits configurable in
crypto/deflate.c.
I wonder, do we really want this?

Imagine we have 100 different compressors, and each is differently configurable. It may make cryptoAPI messy. May be it is better to stand that user must use deflate (and the other 99 compressors) directly if he wants something not standard/compliant?

--
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/