Dpkg::Version: Add new function compare_versions

Emulates the dpkg --compare-versions behaviour (Doesn't support
the -nl operators yet, though). This is often easier to write and
read instead of using vercmp directly.

Also add tests for the new function.

scripts/Dpkg/Version.pm

@@ -162,6 +162,36 @@ sub vercmp ($$)
     return verrevcmp($version{revision}, $refversion{revision});
 }
 
+=item compare_versions
+
+Emulates dpkg --compare-versions. Takes two versions as arguments
+one and three and one operator as argument two. Supports the following
+operators: 'gt', 'ge', 'eq', 'le', 'lt', and '>>', '>=', '=', '<=', '<<'.
+Returns a true value if the specified condition is true, a false value
+otherwise.
+
+=cut
+
+sub compare_versions ($$$)
+{
+    my $rel = $_[1];
+    my $res = vercmp($_[0], $_[2]);
+
+    if ($rel eq 'gt' or $rel =~ />?>/) {
+	return $res > 0;
+    } elsif ($rel eq 'ge' or $rel eq '>=') {
+	return $res >= 0;
+    } elsif ($rel eq 'eq' or $rel eq '=') {
+	return $res == 0;
+    } elsif ($rel eq 'le' or $rel eq '<=') {
+	return $res <= 0;
+    } elsif ($rel eq 'lt' or $rel =~ /<?</) {
+	return $res < 0;
+    } else {
+	die "bad relation '$rel'";
+    }
+}
+
 =back
 
 =head1 AUTHOR

scripts/t/100_Dpkg_Version.t

@@ -26,9 +26,33 @@ my @versions = ({a      => '1.0-1',
 		 result => 0,
 		 relation => 'eq',
 		},
+		{a      => '1.0000-1',
+		 b      => '1.0-1',
+		 result => 0,
+		 relation => 'ge',
+		},
+		{a      => '1',
+		 b      => '0:1',
+		 result => 0,
+		 relation => 'eq',
+		},
+		{a      => '2:2.5',
+		 b      => '1:7.5',
+		 result => 1,
+		 relation => 'gt',
+		},
 	       );
+my @test_failure = ({a      => '1.0-1',
+		     b      => '2.0-2',
+		     relation => 'gt',
+		    },
+		    {a      => '2.2~rc-4',
+		     b      => '2.2-1',
+		     relation => 'eq',
+		    },
+		   );
 
-plan tests => @versions * 2 + 1;
+plan tests => @versions * 3 + @test_failure * 2 + 1;
 
 sub dpkg_vercmp{
      my ($a,$b,$cmp) = @_;
@@ -41,8 +65,16 @@ use_ok('Dpkg::Version');
 
 for my $version_cmp (@versions) {
      ok(Dpkg::Version::vercmp($$version_cmp{a},$$version_cmp{b}) == $$version_cmp{result},
-	"Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b} ok");
+	"vercmp: Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b} ok");
+     ok(Dpkg::Version::compare_versions($$version_cmp{a},$$version_cmp{relation},$$version_cmp{b}),
+       "compare_versions: Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b} ok");
      ok(dpkg_vercmp($$version_cmp{a},$$version_cmp{b},$$version_cmp{relation}),
 	"Dpkg concures: Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b}");
 }
 
+for my $version_cmp (@test_failure) {
+     ok(!Dpkg::Version::compare_versions($$version_cmp{a},$$version_cmp{relation},$$version_cmp{b}),
+       "compare_versions: Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b} false");
+     ok(!dpkg_vercmp($$version_cmp{a},$$version_cmp{b},$$version_cmp{relation}),
+	"Dpkg concures: Version $$version_cmp{a} $$version_cmp{relation} $$version_cmp{b}");
+}