[Squeak Installer] Support for .gz

Andreas Raab Andreas.Raab at gmx.de
Wed Oct 10 06:04:48 UTC 2001


>     How can I use the existing ZipPlugin to uncompress a gzipped file
> without the interpreter.

You don't (see below).

>     BTW, I just built a Zlib.dll and it is a whoppy 59KB vs 18KB for
> ZipPlugin.dll. What made the difference ?

We're only doing the time-critical stuff in the primitives. All the
high-level stuff is handled from Squeak itself. Which means that the 40k
difference come from C code that can equally well be handled by much smaller
piece of Squeak byte codes (though I don't know how much exactly).

> Performance wise (speed, compression ratio), how does ZipPlugin
> compare to Zlib ?

Not having benchmarked it all I can guess is that for decompression speed
Squeak should be within a factor of 1.5 of ZLib. Compression speed will be
somewhat slower (possibly up to a factor of 3) and compression ratio should
be almost the same[**]. Note that this comparison holds only if ZLib hasn't
been specifically optimized. Some of the LZ77 implementations I've seen had
a bit of assembly code in those few crucial loops and they do make quite a
bit of a difference.

[**] Of course, compression speed and ratio are depending on various input
parameters so the comparison assumes roughly the same settings.

Cheers,
  - Andreas





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