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Re: vcdiff generator status?

From: Greg Hudson <ghudson_at_MIT.EDU>
Date: 2000-09-12 18:06:16 CEST

> "Given a source string and a delta, you can't construct the inverse
> delta"

> The latter is the situation I'm in. And I know I can do it: at the
> very worst, I could apply the delta to the source string to produce
> the target string and then run the delta algorithm again with the
> arguments reversed. However, I'm hoping that with fancy arithmetic
> I could do better.

I doubt it. The delta constructs the target in linear order, but has
essentially random access to the source.

There are also some special cases where you definitely have to go to
all the work. Suppose the source is an interesting block of data but
the target is an empty string, or something boring like a run of
zeros. There's clearly no way you can avoid the effort of compressing
the source data in that case.
Received on Sat Oct 21 14:36:08 2006

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