[eclass] Add perl-version.eclass which can turn normalised forms into floats

1 files changed, 91 insertions, 0 deletions

diff --git a/eclass/perl-version.eclass b/eclass/perl-version.eclass
new file mode 100644
index 000000000..97022e2be
--- /dev/null
+++ b/eclass/perl-version.eclass
@@ -0,0 +1,91 @@
+# Copyright 1999-2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: $
+
+# @ECLASS: perl-versions.eclass
+# @MAINTAINER:
+# perl@gentoo.org
+# Kent Fredric <kentnl@cpan.org>
+# @BLURB: Perl versioning functions
+# @DESCRIPTION:
+# The perl-version eclass contains an assortment of functions for denormalizing versions
+# in order to streamline version bumps and minimise risk of accidental failure to update
+# MODULE_VERSION and unify all the ways of turning arbitrary normalised versions back into
+# a form used upstream.
+
+# expand-tail 5 => 005
+# expand-tail 5.5 => 005005
+perl-version-expand-tail() {
+	local tail=$1
+	if [ -z "${tail}" ]; then
+		echo '000';
+		return;
+	fi
+	# Tail with no segments
+	if [ "${tail%%.*}" = "${tail}" ]; then
+		printf "%03d" "$tail"
+		return;
+	fi
+	local head="${tail%%.*}"
+	local rest=$( perl-version-expand-tail "${tail#*.}" )
+	printf "%03d%s" $head $rest;
+	return;
+}
+
+# float 5.1   => 5.001
+# float 5.10  => 5.010
+# float 5.100 => 5.100
+# float 5.1.1 => 5.001001
+perl-version-float() {
+	local version=$1
+	local major=${version%%.*}
+	local tail=${version#*.}
+	if [ "$tail" = "$version" ]; then
+		tail=000;
+	else
+		tail=$( perl-version-expand-tail "${tail}" )
+	fi
+	printf "%s.%s" "$major" "$tail";
+	return;
+}
+
+# float_n 5.201.505.200 8 => 5.20150520
+perl-version-float_n() {
+	local version=$1
+	local mantissa=$2
+	local major=${version%%.*}
+	if [ "$mantissa" -lt 1 ]; then
+		printf "%s" $major;
+		return;
+	fi
+	local tail=${version#*.}
+	if [ "$tail" = "$version" ]; then
+		tail=000;
+	else
+		tail=$( perl-version-expand-tail "${tail}" )
+	fi
+	if [ "${#tail}" -lt $mantissa ]; then
+		local pad=$(( $mantissa - ${#tail} ));
+		printf "%s.%s%0${pad}d" "${major}" "${tail}" 0
+		return
+	fi
+	printf "%s.%s" "${major}" "${tail:0:$mantissa}"
+}
+
+# denormalize 5.201.505.200 float_n 8 => 5.20150520
+perl-version-denormalize() {
+	local version=$1;
+	local scheme=$2;
+	shift
+	shift
+	case "${scheme}" in
+		"float_n")
+			perl-version-float_n $version "$@"
+			return
+			;;
+		*)
+			die "Unknown version scheme ${scheme}"
+			;;
+	esac
+}
+