Re: Updated Delta+BOHE Impl in Java

[Martin Thomson <[e-mail]>]

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 <[e-mail]> 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
>