[LAD] "enhanced event port" LV2 extension proposal

Dave Robillard dave at drobilla.net
Wed Dec 5 03:24:34 UTC 2007

On Tue, 2007-12-04 at 09:42 +0000, Krzysztof Foltman wrote:
> Dave Robillard wrote:
> > Using a uint32_t (which is a reasonable limit for number of symbols in
> > pretty much any system) and just not using out of range numbers for the
> > event ones doesn't seem so bad, just in case.  It's one line in a
> > comment somewhere, BFD.
> I'm thinking of something else - like having different "domains" for
> mappings. Like http://whatever/parameter-value gets number 10 in
> URI-to-event-type mapping, and number 16777216 in URI-to-global-numbers
> mapping. Basically, same class (URI-to-int mapper), different objects
> (event type URI registry, plugin port URI registry, plugin URI registry,
>  and so on). Different dictionaries, same dictionary interface.
> I'm not insisting this is a good idea - just that it could solve the
> "max 65536 types" thing nicely while preserving some (not all)
> generality. It could also lead to a mess if somebody used wrong type ID
> (when the same URI is in two registries).

Not really 'nicely'... essentially implementing the exact same thing n
times.  Why bother?

> Also, I would be for a requirement that numbers are always assigned (by
> host) sequentially starting from 0, not by - for example - hashing,
> because then some plugins could use small arrays to store
> event-type-to-handler mapping (or
> something-id-to-whatever-data-structure). Is that OK?

The interface for the dynamic part would have to be figured out before
this can be decided.

> What about this (translate it to C in your heads :) ):
> interface IURIRegistryObserver
> {
>   // function in plugin etc. called by host whenever new URI is registered
>   void mapping_added(int id, const char *uri);
> };
> interface IURIRegistry
> {
>   int uri_to_id(const char *uri, bool create_if_absent);
>   const char *id_to_uri(int id);
>   void add_observer(IURIRegistryObserver *observer);
>   void remove_observer(IURIRegistryObserver *observer);
> };
> interface IURIRegistries
> {
>   IURIRegistry *get_registry(const char *registry_uri);
> };

... did I stumble on to the Java 101 mailing list by mistake? ;)


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