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

Hello everybody :)

I've been trying to write some scripts to compare versions of packages, mainly RPM package names. I wrote something that can compare two versions together, but it's quite sloppy and doesn't work if there are letters involved in a package name. I was wondering if there is anybody else out there that has done something similar?

I'd be looking to compare something like mozilla-1.4.2-3.0.2 and mozilla-1.4-3.0.18 or something like mozilla-1.4.2r-3.0.2 and mozilla-1.4g-3.0.18. I'm sure you get the idea. Thanks.

Replies are listed 'Best First'.
Re: Version checking
by tachyon (Chancellor) on Sep 30, 2004 at 04:32 UTC

    The basic approach to this sort of problem is to normalize the strings so you can just do a simple alphabetic sort on them. This means padding out the data so that the sort will work correctly. I am not sure exactly how the letters are supposed to sort but something like this will get you on track. 

    @data = qw(
    mozilla-1.4.2-3.0.2     mozilla-1.40-3.0.18     mozilla-1.4.2r-3.0
+.2
    mozilla-1.4g-3.0.18     mozilla-1.4.1-3.0.2     mozilla-1.4-3.0.7
    mozilla-1.4g-3.1.18     mozilla-1.4-3.0.1       mozilla-1.4-3.0.71
    mozilla-1.4.2s-3.0.2    mozilla-1.4-3.0.18      mozilla-1.4a-3.0.1
+8
);

@data = map{[ normalize($_), $_]}@data;
@data = sort { $a->[0] cmp $b->[0] } @data;

printf "%s\t%s\n", $_->[0], $_->[1] for @data;

sub normalize {
    my $str = shift;
    $str =~ s/(\-\w+\.\w+)\-/$1.0-/;
    #return join '', map{ sprintf "%3s", $_ }split m/[\-\.]/, $str;
    return join '', map{ s/^(\d+)(\w*)$/sprintf "%3s%1s", $1, $2?$2:' 
+'/e; $_ }split m/[\-\.]/, $str;
}

__DATA__
mozilla  1   4   0   3   0   1     mozilla-1.4-3.0.1
mozilla  1   4   0   3   0   7     mozilla-1.4-3.0.7
mozilla  1   4   0   3   0  18     mozilla-1.4-3.0.18
mozilla  1   4   0   3   0  71     mozilla-1.4-3.0.71
mozilla  1   4   1   3   0   2     mozilla-1.4.1-3.0.2
mozilla  1   4   2   3   0   2     mozilla-1.4.2-3.0.2
mozilla  1   4   2r  3   0   2     mozilla-1.4.2r-3.0.2
mozilla  1   4   2s  3   0   2     mozilla-1.4.2s-3.0.2
mozilla  1   4a  0   3   0  18     mozilla-1.4a-3.0.18
mozilla  1   4g  0   3   0  18     mozilla-1.4g-3.0.18
mozilla  1   4g  0   3   1  18     mozilla-1.4g-3.1.18
mozilla  1  40   0   3   0  18     mozilla-1.40-3.0.18

    [download]

    cheers

    tachyon

[reply]
[d/l]
Re: Version checking
by dragonchild (Archbishop) on Sep 29, 2004 at 19:53 UTC
    Why? Redhat already has this code written. Look at the RPM manager(s) that come with Fedora Core. You might have to read some Python, but you might get lucky - Inline::Python can help you out.

    Being right, does not endow the right to be rude; politeness costs nothing.
    Being unknowing, is not the same as being stupid.
    Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
    Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

    I shouldn't have to say this, but any code, unless otherwise stated, is untested

[reply]
      Mainly because I'll need to test other things other than just Red Hat systems, I'll also need to test versions on AIX, Solaris, and other Linux systems.
[reply]
        The fact that RedHat (and most other vendors) wrote this code has no bearing on what systems the code will run. I meant to say that you should sourcedive the RPM manager and lift the version-checking code from it. (Or apt-get, if you're Debian-inclined.)

        Being right, does not endow the right to be rude; politeness costs nothing.
        Being unknowing, is not the same as being stupid.
        Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
        Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

        I shouldn't have to say this, but any code, unless otherwise stated, is untested

[reply]
Re: Version checking
by Anonymous Monk on Sep 30, 2004 at 06:07 UTC
[reply]

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