[project @ 2003-09-07 22:09:48 by cjwatson]

New Debbugs::Versions::Dpkg module implementing pure-Perl comparison of
dpkg-style version numbers. Used when libapt-pkg-perl isn't available and
'dpkg --compare-versions' is too slow.

diff --git a/Debbugs/Versions/Dpkg.pm b/Debbugs/Versions/Dpkg.pm
new file mode 100644 (file)
index 0000000..064618f
--- /dev/null
+++ b/Debbugs/Versions/Dpkg.pm
@@ -0,0 +1,120 @@
+package Debbugs::Versions::Dpkg;
+
+use strict;
+
+=head1 NAME
+
+Debbugs::Versions::Dpkg - pure-Perl dpkg-style version comparison
+
+=head1 DESCRIPTION
+
+The Debbugs::Versions::Dpkg module provides pure-Perl routines to compare
+dpkg-style version numbers, as used in Debian packages. If you have the
+libapt-pkg Perl bindings available (Debian package libapt-pkg-perl), they
+may offer better performance.
+
+=head1 METHODS
+
+=over 8
+
+=cut
+
+sub parseversion ($)
+{
+    my $ver = shift;
+    my %verhash;
+    if ($ver =~ /:/)
+    {
+       $ver =~ /^(\d+):(.+)/ or die "bad version number '$ver'";
+       $verhash{epoch} = $1;
+       $ver = $2;
+    }
+    else
+    {
+       $verhash{epoch} = 0;
+    }
+    if ($ver =~ /(.+)-(.+)$/)
+    {
+       $verhash{version} = $1;
+       $verhash{revision} = $2;
+    }
+    else
+    {
+       $verhash{version} = $ver;
+       $verhash{revision} = 0;
+    }
+    return %verhash;
+}
+
+sub verrevcmp ($$)
+{
+    my ($val, $ref) = @_;
+    for (;;)
+    {
+       $val =~ s/^(\D*)//;
+       my $alphaval = $1;
+       $ref =~ s/^(\D*)//;
+       my $alpharef = $1;
+       if (length $alphaval or length $alpharef)
+       {
+           my @avsplit = split //, $alphaval;
+           my @arsplit = split //, $alpharef;
+           my ($av, $ar) = (0, 0);
+           while ($av < @avsplit and $ar < @arsplit)
+           {
+               my ($v, $r) = (ord $avsplit[$av], ord $arsplit[$ar]);
+               $v += 256 unless chr($v) =~ /[A-Za-z]/;
+               $r += 256 unless chr($r) =~ /[A-Za-z]/;
+               return $v <=> $r if $v != $r;
+               $av++;
+               $ar++;
+           }
+           return 1 if $av < @avsplit;
+           return -1 if $ar < @arsplit;
+       }
+
+       return 0 unless length $val and length $ref;
+
+       $val =~ s/^(\d*)//;
+       my $numval = $1;
+       $ref =~ s/^(\d*)//;
+       my $numref = $1;
+       return $numval <=> $numref if $numval != $numref;
+    }
+}
+
+=item vercmp
+
+Compare the two arguments as dpkg-style version numbers. Returns -1 if the
+first argument represents a lower version number than the second, 1 if the
+first argument represents a higher version number than the second, and 0 if
+the two arguments represent equal version numbers.
+
+=cut
+
+sub vercmp ($$)
+{
+    my %version = parseversion $_[0];
+    my %refversion = parseversion $_[1];
+    return 1 if $version{epoch} > $refversion{epoch};
+    return -1 if $version{epoch} < $refversion{epoch};
+    my $r = verrevcmp $version{version}, $refversion{version};
+    return $r if $r;
+    return verrevcmp $version{revision}, $refversion{revision};
+}
+
+=back
+
+=head1 BUGS
+
+Version numbers containing the C<~> character, used for pre-releases of
+packages, are not yet supported.
+
+=head1 AUTHOR
+
+Colin Watson E<lt>cjwatson@debian.orgE<gt>, based on the implementation in
+C<dpkg/lib/vercmp.c> by Ian Jackson and others.
+
+=cut
+
+1;