[xsd-users] Re: Embedded XSD for games...

[sam scott]

Brilliant this looks like the job - I thought I may have over complicated
the task at hand.

I need to spend some time looking at this avenue to fully assess whether it
fully meets my needs, but in any case thank you very much for the speedy
response!

On 14/05/07, Boris Kolpackov <boris at codesynthesis.com> wrote:
>
> Hi Sam,
>
> I think xsd-users is a more appropriate place to discuss this. I've
> CC'ed it to my reply.
>
> I am not sure if you looked into this but from your description it
> appear that the binary serialization of the in-memory representation
> can do what you want. The idea of this feature is that you can
> instruct XSD (see the --generate-insertion and --generate-extraction
> options as well as the 'binary' example) to generate stream insertion
> operators and extraction constructors. Pretty much any custom stream
> type can be used. ACE CDR (CORBA over-the-wire format) is supported
> out of the box. We've done some measurements and the resulting
> representation is a lot smaller and faster to parse.
>
> This would work like so: you will generate two version of the C++
> code from your schema. The first is for the PC and will include XML
> parsing and binary serialization code. The second is for the console
> and will only include binary extraction code without any XML stuff.
> The PC code will parse XML, serialize to binary format, and send
> it to the console. The console will extract the data from the
> binary format which can then be used by the application.
>
> Let me know if I missed anything from your requirements.
>
> hth,
> -boris
>
>
> [The original email follows for context.]
>
> sam scott <billythefisherman at googlemail.com> writes:
>
> > Hi Boris (no one else seems to post here!) - I hope I've got this post
> in
> > the right place but that's really what I'm trying to find out.  I'm
> writing
> > an article which I hope to post on a game development website which
> proposes
> > an 'ideal' pipeline for getting all our data requirements through one
> > conversion utility from the many different source applications we use.
> >
> > All of these source apps (Maya, Proprietary Editor, MS Office) output
> XML in
> > varying formats and need converting to binary versions PC side - we're
> > incredibly data heavy and so any processing of XML data on the console
> side
> > is really out of bounds.  So at home I've started to experiment with
> your
> > xsd lib which is fantastic it must be said but have found one large
> problem
> > to do with my problem domain.
> >
> > The problem goes like this: to get binary data off of the PC to console
> i
> > must deal with two problems: pointers and virtual table pointers.  The
> > former is easy and the latter a little less so but none the less
> possible
> > I actually use a lib from an article in Games Programming Games 5: "1.13A
> > Transparent Class Saving and Loading Trick".  This basically replaces
> all
> > the pointers with a special 'smart pointer' which then gets turned into
> an
> > offset and put into a table at save time (PC side) and remapped out to
> the
> > correct memory address at load time (console side).
> >
> > This means that due to the autogenerated nature of XSD and XSDe,
> > I have to add in an extra conversion step PC side to:
> >
> > a) turn all the pointers into freeze pointers
> > b) strip down the data structures to there bare
> > bones (most just need to be simple arrays and structures) - actually
> XSDe
> > seems to provide a solution this point
> > c) remove as much inheritance as possible (usually i don't want any as
> > dealing with moving vtbl pointers over to target platform is a royal
> pain)
> >
> > This step is error prone and time consuming and goes against the reason
> of
> > using an XML data binding step - the data binding helps but I feel I
> should
> > be able to get to this format direct ie use the auto generated data
> > structures console side)
> >
> > So (and we fianlly get to the meat and potatoes here) to solve all my
> > problems I get the feeling I need to use your xsd frontend to write my
> own
> > version of XSD which fills my requirements: do you think this is so or
> is
> > there a method you've already devised of to deal with this type of
> > situation?
> >
> > Thanks
>
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