Re: [RFC] LZO de/compression support - take 6

From: Satyam Sharma
Date: Thu May 31 2007 - 14:21:37 EST


On 5/31/07, Nitin Gupta <nitingupta910@xxxxxxxxx> wrote:
[...]
The author (Markus Oberhumer) of LZO provided these comments for this patch:

---
I've only briefly looked over it, but it's obvious that your version does not
work on architechtures which do not allow unaligned access (arm, mips, ...).

As for further quality assurance, your version should generate byte-identical
object code to LZO 2.02 when using the same compiler & flags. So you could do
some semi-automatic testing by compiling with -ffunction-sections and use
"objcopy --only-section .text.XXX" to compare the md5sum of all generated
functions. This also works fine with crosscompilers.

Finally I'm not too happy that you renamed the functions and #defines like
LZO1X_WORKMEM_SIZE - please stay compatible with the official library version.

As suggested by Johannes earlier, it'd be great if you could submit
the various changes (as per Changelog) as _individual patches_ on
the original userspace code. That would be easier for others to review,
and there's lesser chances of bugs / issues leaking in that way.

As for "byte-identical object code", I definitely do *not* think it is
necessarily a requirement / good idea. As long as all the changes
you make are reviewed individually / closely by people here on this
list, there's very low chances of any bugs creeping in. [ F.e. I see
nothing wrong in removing the usage of "register" -- that could clearly
lead to different object code, but with no bugs introduced. ]
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