[LAD] "enhanced event port" LV2 extension proposal

Krzysztof Foltman wdev at foltman.com
Thu Dec 6 09:33:40 UTC 2007

Lars Luthman wrote:

> That sounds OK. I suggest something like this:
> struct URI_Mapper {
>   // call this with your URI and the host_data member - not RT safe
>   uint16_t (map_function*)(const char* uri, void* host_data);
>   // pass this as the second parameter to map_function()
>   void* host_data;
> };
> It doesn't provide a way for the host to say "I'm out of IDs!" though.
> Will that be needed?

What about using int32_t and returning -1 as "out of IDs"? There's no
difference in CPU time spent anyway, because uint16_t is returned in the
same 32-bit register as int32_t is (eax, on x86).

Or you can use 0 (or 65535) for error. It doesn't look like something
that requires lots of thinking.

Also, a reverse mapping mechanism would be helpful at times (for
debugging/data monitors). I put it in my proposal for that specific
reason. It shouldn't be hard to implement, either (might be a waste of
memory, but of acceptable kind).

Or it might be a separate feature, so that certain people won't get too
confused ;)


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