From: Daniel Berger <djberg96@...>
Date: 2009-01-10T02:27:08+09:00
Subject: Re: Pure Ruby Zlib::GzipWriter

Hi,

On Jan 8, 8:23 pm, "Heesob Park" <pha...@gmail.com> wrote:
> 2009/1/8 Daniel Berger <djber...@gmail.com>:
>
> > On Jan 7, 11:08 pm, "Heesob Park" <pha...@gmail.com> wrote:
> >> Hi,
>
> >> 2009/1/8 Charles L. <aquas...@gmail.com>:> Daniel Berger wrote:
>
> >> >> Sounds like you're on track. But, you're in a race with Park Heesob. :)
>
> >> >> Dan
>
> >> > Heh. :) Somehow I think he's got it covered. That reimplementation of
> >> > zlib in ruby is actually pretty cool. I'm curious Park, as to how much
> >> > you did by hand and how much you were able to automate it...?
>
> >> I dit it all by hand. There is no royal road to translating C to Ruby:)
>
> >> > I've put the deflate code i wrote on pastie -http://pastie.org/355367
>
> > Excellent, thanks!
>
> >> > It's about 600 lines, but needs cleaning up. Will probably be ~500 when
> >> > I've added in dynamic trees and cleaned it up a bit.
>
> >> > Prelim benchmarks show the current bottleneck to be the LZ77
> >> > implementation which is interesting. I think for it to perform
> >> > acceptably, a lot more of the code needs to become more idiomatic,
> >> > higher-level ruby.
>
> >> In my test, the deflation is very slow but the inflation is endurable.
> >> Moreover, for the compatibility of the various Ruby version, It shows
> >> bad performance in Ruby 1.8.x.
>
> > As long as it's usable I'm happy. We can benchmark, profile and
> > optimize later. :)
>
> Finally I translated the whole zlib.c to ruby code.
> You can download athttp://121.78.227.9/rbzlib/pzlib.rb

Looks very promising but doesn't quite work yet:

C:\>gem install ptools
ERROR:  While executing gem ... (NoMethodError)
    undefined method `ZSTREAM_IS_FINISHED' for #<Zlib::GzipReader:
0x2f8e8bc>

I think you need some tests. ;)

BTW, I'm assuming this is basically a wholesale replacement of zliby?
If so, the module should be renamed from PZlib to just Zlib.
Otherwise, Rubygems will complain about the lack of a Gem::Zlib
definition.

Keep up the good work!

Regards,

Dan