[pacman-dev] [PATCH] pkgdelta: Use high compression options offered by xdelta3

[Mohammad Alsaleh]

 * Add -9 which is the highest compression level.
 * Use lzma for secondary compression.

 Decompression speed is largely unaffected as most cycles are consumed
 by xz for re-compression.

 Some numbers:

 clang x86_64 [3.5.0-2.1 to 3.5.0-3]
 17.21MiB      default      (0.73)
 15.67MiB      -9           (0.67)
 13.59MiB      -9 -S djw    (0.58)
 12.01MiB      -9 -S lzma   (0.51)

 inkscape x86_64 [0.48.5-3 to 0.48.5-4]
 02.69MiB      default      (0.21)
 01.64MiB      -9           (0.13)
 01.30MiB      -9 -S djw    (0.10)
 01.01MiB      -9 -S lzma   (0.08)

Signed-off-by: Mohammad Alsaleh <CE.Mohammad.AlSaleh at gmail.com>
---
 scripts/pkgdelta.sh.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/pkgdelta.sh.in b/scripts/pkgdelta.sh.in
index be49326..fe63974 100644
--- a/scripts/pkgdelta.sh.in
+++ b/scripts/pkgdelta.sh.in
@@ -140,7 +140,7 @@ create_xdelta()
 	deltafile=$(dirname "$newfile")/$pkgname-${oldver}_to_${newver}-$arch.delta
 	local ret=0
 
-	xdelta3 -q -f -s "$oldfile" "$newfile" "$deltafile" || ret=$?
+	xdelta3 -q -f -9 -S lzma -s "$oldfile" "$newfile" "$deltafile" || ret=$?
 	if (( ret )); then
 		error "$(gettext "Delta could not be created.")"
 		return 1
-- 
2.2.0