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Re: A simple (?) suggestion from a svn fan :)

From: mark benedetto king <mbk_at_boredom.org>
Date: 2003-02-24 19:41:01 CET

On Mon, Feb 24, 2003 at 11:54:51AM -0800, Ben Collins-Sussman wrote:
>
> Internally, Subversion uses a binary diff algorithm to express all
> file differences, regardless of whether a file contains text or binary
> data. So when you store successive versions of a binary file in a
> Subversion repository, you *are* getting differential (compressed)
> storage. (CVS, because it uses RCS, has to store the entire binary
> file over and over.)
>
> So in this sense, Subversion is already doing what you wish.
>

It's likely that a change to the first byte of an uncompressed file
would change the entirety of the compressed file, making the binary
diffs much less efficient than text diffs.

You might argue that a random change is likely to occur, on average,
in the middle of the file, but XML files have a habit of changing
near the beginning, due to informational/header records.

This is really just a special case of "I have a way of performing
and encoding the results of a semantic rather than lexical comparison
between files of this type".

The sooner we have hooks for this the better.

--ben

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Received on Mon Feb 24 19:41:59 2003

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