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DIFF format sketch

From: <edgar@edgarschwarz.de>
Date: Sat, 30 Jun 2007 23:40:33 +0200 (MEST)
To: ietf-http-wg@w3.org
Cc: edgar@edgarschwarz.de
Message-ID: <c01a42j5UL0Xby.RZmta@mo-p07-ob.rzone.de>

Hi all,
I remember we discussed PATCH a while ago (perhaps in a different list ?) and we
also feared IPR problems. And so the discussion went to sleep :-(
Then and now I would like to have a basic required text and binary diff format.

IIRC someone argued that the standard text diff used in Unix diff is free to use.
Concerning a binary format I can imagine to use a simple,obvious binary format
which is fine for the vanilla usecase of changing some small parts of a resource.

E.g.:
a(dd from PATCH body) <number of octets> CRLF
<octets> CRLF
c(opy from original) <offset from current position in original> <number of octets> CRLF

Perhaps the offset can also be negative to allow swapping stuff but it should
be good enough to be useful even if the offset is strictly positive.
Or perhaps you want to put the different segment in chunks ?
Whatever, I can't imagine that such an obvious format could have any IPR problems.
OTOH, it's good enough for most cases of patching.
For other aspects like registering a MIME type or similar stuff I hope the specialists
have a solution.

Cheers, Edgar 
Received on Saturday, 30 June 2007 21:40:38 GMT

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