pjc has asked for the wisdom of the Perl Monks concerning the following question:

Has anyone written a version of gzip in pure perl?
What I mean by "pure perl" is the script doesn't
use backticks (``) or the system() command.

Here's the RFC on GZIP:
http://www.ietf.org/rfc/rfc1952.txt

I'd like to use it as a drop in replacement for
the binary gzip on different Unix machines.

Thanks,

pjc

update (broquaint): removed <code> tags and added appropriate formatting

Replies are listed 'Best First'.
Re: gzip written in perl
by graff (Chancellor) on Nov 04, 2002 at 03:29 UTC
    With Perl 5.8, you can also use PerlIO::gzip and read/write gzip data though an IO layer -- e.g. here's a script that reads a gzipped file, numbers the lines, and writes the result to a new gzipped file: 
    use PerlIO::gzip;

open IN, "<:gzip", "somefile.gz" or die "$!\n";
open OUT, ">:gzip", "numbered.gz" or die "$!\n";
while (<IN>) {
    print OUT join " ", ++$i, $_;
}

    [download]
    (God, I love it!)

    UPDATE: (2010-10-18) It seems that PerlIO::gzip should be viewed as superseded by PerlIO::via:gzip. (see PerlIO::gzip or PerlIO::via::gzip).

[reply]
[d/l]
Re: gzip written in perl
by grep (Monsignor) on Nov 04, 2002 at 03:13 UTC
    A quick search of cpan gives me Compress::Zlib which has gzip support.

    grep
    Mynd you, mønk bites Kan be pretti nasti...
[reply]
      A while back I tried to use Compress::Zlib at a customer's site, but it requires the use of an external library. They were OK with installing a pre-built binary (gzip lib), but refused to load a compiler onto their production box (a 5.0 Tru64 machine). The only available pre-built binary was part of a larger suite that was only available on CD...not much use when I was only on-site for a couple of days. A pure-perl gzip would have been very handy indeed.

      rdfield

[reply]
      ActivePerl includes it for Windoze machines. It works fine for production here.
[reply]
        hi i am new at perl can you teach me how to compress a file in a directory
[reply]
Re: gzip written in perl
by strredwolf (Chaplain) on Nov 04, 2002 at 22:20 UTC
    I can tell you, it'll be slow. But that'll be useful to do it, though. There is a C version of gunzip that's nicely small off of the IOCCC.

    --
    $Stalag99{"URL"}="http://stalag99.keenspace.com";

[reply]

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