Re: Patch for transparent decompression

[Reuben Thomas]

On Sun, 27 Apr 2008, Tony Abou-Assaleh wrote:

> * The patch statically links with libz at compile time. If grep is installed 
> before libz, then it would need to be recompiled. Ideally, the user should 
> have an option of forcing static linking, use dynamic linking, or totally 
> disabling the option. How complicated is it to get that working?

Not too hard.

> I remember there was a patch that tried to do this for -P, but I couldn't 
> locate it. Need to dig deeper.

That was mine too, I didn't submit it yet to the tracker because I was 
trying to get this one accepted first. I shall instead update the 
transparent decompression patch to use the same dynamic linking techniques.

> * In addition to documentation, I'd like to see some test cases. And the more 
> the better :O)

I'm not good at thinking of these; I'd be happy for any hints.

> * My understanding is that zlib support .gz files. Any plans to integrate 
> libbzip2 as well?

This is a nasty one. I see three options:

1. [Easiest for grep] Add code to grep to determine what sort of compression 
we're looking at. Currently we don't have to do this.

2. [A bit cleaner, a bit slower] Write a little library that decides whether 
to delegate to libbzip2 or libz for a given stream.

3. [Nicest solution, slowest and most difficult to get accepted] Patch libz 
so that it can delegate to libbzip2 for bzipped files (or vice versa), and 
just use the one interface.

> And a question to the community: is --uncompress a good option name? Any 
> objections? Zlib uses the term 'decompress'.

I'd be happy to change; I think "decompress" is actually better.

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