Re: [RFC] CryptoAPI & Compression

Artem B. Bityuckiy
2005-04-03T12:01:25Z

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?