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Re: Updated Delta+BOHE Impl in Java

From: Martin Thomson <martin.thomson@gmail.com>
Date: Tue, 9 Apr 2013 10:37:58 -0700
Message-ID: <CABkgnnWyx2k7SHt=1+YDBMtvDArWqUz-mfXbe8gh6KjUdLGdPQ@mail.gmail.com>
To: James M Snell <jasnell@gmail.com>
Cc: "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
This is great news.

Out of interest: Where did you derive the values you used to build
your Huffman tables?

On 9 April 2013 10:24, James M Snell <jasnell@gmail.com> wrote:
> I have updated my experimental Delta+Bohe java implementation to match
> the current draft of the specification and Roberto's current delta
> iteration. I still have to patch this in to the compression-test stuff
> but the code is functional.
>   https://github.com/jasnell/http2
> Requires maven to build. Dependencies are light. Still needs a ton of
> work and I have not even started working on performance optimizations.
> It's a pretty straight forward port of everything Roberto has done in
> the python impl.
> The one bit this does add is multi-type header values. The types
> supported are String, Number, Datetime and Binary. Strings can be
> either UTF-8 or ISO-8859-1. If they are ISO-8859-1, they can be
> Huffman coded using Roberto's static code. I am using an different
> static dictionary of predefined header values tho.
> General takeaways ..
> 1. The implementation is not that difficult to do and seems to perform
> reasonably well.
> 2. The additional types are very useful and add minimal additional
> complexity to the implementation.
> 3. I'm generally not convinced that we really need the huffman coding.
> Yes, it saves a handful of bytes here and there but it does add
> additional complexity. I can live with it tho. If we keep it and we
> decide to allow for UTF8 header values, then we need to come up with a
> static huffman coding that includes the extended UTF8 character
> support.
> 4. Performance seems reasonable overall.
> I'm going to be working on implementing HeaderDiff next. Hopefully
> I'll have the time to have that done by this Friday.
> - James
Received on Tuesday, 9 April 2013 17:38:26 UTC

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