RPM deltaing tool

[M A Young <m a young durham ac uk>]

I posted the following email as part of a discussion, on the fedora-devel
mailing list, as part of a discussion on RPM deltas for Fedora. My
interest is as to whether a general RPM deltaing utility is worth
developing further, and whether the rpm developer community have any
strong opinions on how such a utility should work.

Note that the attached scripts do reconstuct the target rpm byte for byte,
and could quite easily be turned into a usable application without much
work, though it could be done more efficiently.

        Michael Young

---------- Forwarded message ----------
To: fedora-devel-list@redhat.com
Subject: Updating RPMs using binary deltas (demo)

Here is a couple of demo short scripts for generating and applying deltas
between two rpms. The key step is to use the minigzip program from the
zlib source (see the docs directory of the zlib-devel package), as
minigzip uses compression compatible with the compression rpm uses. If I
was writing this properly, I would consider using python, which seems to
have a zlib modules, and could also hook into some rpm libraries.

	Michael Young

Attachment: makerpmdelta.sh
Description: makerpmdelta.sh script

Attachment: applyrpmdelta.sh
Description: applyrpmdelta.sh script