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Re: [hybi] deflate-stream and masking

Dirkjan Ochtman <dirkjan@ochtman.nl> Mon, 20 June 2011 08:38 UTC

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From: Dirkjan Ochtman <dirkjan@ochtman.nl>
Date: Mon, 20 Jun 2011 10:37:43 +0200
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To: Greg Wilkins <gregw@intalio.com>
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Cc: Hybi <hybi@ietf.org>
Subject: Re: [hybi] deflate-stream and masking
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On Mon, Jun 20, 2011 at 08:33, Greg Wilkins <gregw@intalio.com> wrote:
> As an unmasked WS stream, it was 50675 bytes, and as a masked stream
> is was 52623 bytes.
> I then compressed both these streams with gzip and got 13306 bytes for
> unmasked and 51704 bytes for the masked!!!!

Are you sure you got this right? From the RFC:

"The masking does not affect the length of the payload data."

Which means it's a little strange that your unmasked WS stream has a
different size from the masked stream.

(Still, it's fairly intuitive that masking would result in worse
compression, so I would tend to agree that compress-then-mask
makes more sense than mask-then-compress.)

Cheers,

Dirkjan

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