Re: [xml] Compressed Documents

[Daniel Veillard <veillard redhat com>]

On Sun, Sep 07, 2003 at 02:40:47AM +0800, William M. Brack wrote:
> I'm working on a bug report
> (http://bugzilla.gnome.org/show_bug.cgi?id=120503), and would to ask
> for further input from the list.
> 
> The reporter has pointed out that the compression mode of the input
> document can be important to the library user, and without knowing
> it the output mode of a document may not match the input.  At the
> moment, the library does not set the compression (i.e.
> xmlSetDocCompression is not called by any routine within the
> library).
> 
> >From my (limited) understanding of the gzip library, I think I can
> determine, when a document is first opened, whether the input file
> was compressed or not.  However, it appears there is no way to
> determine which compression "mode" (1-9) was used.  So, I have two
> questions which I would like to open up to the list:-
> 
> 1) Should the library set the compression mode of the document on
> input?  The result of doing this would be that, if no action were
> taken by the user, if an input document (which was compressed) were
> written out it would be written as a compressed file (rather than
> uncompressed as now).

  yeah, it used to work in libxml1 a long time ago, and that was dropped
at some point, I don't know why. Just make really sure that we do that only
on document which were compresed on open :-)

> 2) If the library is to set the mode as compressed, what "mode"
> should be used (and if anyone knows how I can determine the original
> compression mode of the input file, please advise)?  Is it better to
> set it as "1" (minimum compression), or "9" (maximum compression),
> or some other value?  Bear in mind that the user can always override
> whatever default mode is set.

  I think 9 should be the default. When CPU were really slower it did
matter, now I think we shouldn't bother anymore.

Daniel

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