From: Justin Johnson <justinj@...>
Date: 2002-07-04T00:53:42+09:00
Subject: Re: Ruby implementation Q's


> x = BitMapLoader.new();
>
> x.loadbitmap("image.tga");
> x.dosomethingwiththedata();
> x.unloadbitmap();

Yes, this is the explicit case.  It's kind of how you'd do it in a language
like C.
I'm still trying to think if there's a way of automating it and making it an
OO feature, which I think would be necessary for working properly with
exceptions and transparency (just like the 'initialise' method).

--
Justin Johnson
justinj@mobiusent.com
Technical Director
Mobius

"Peter Hickman" <peter@semantico.com> wrote in message
news:3D230784.40607@semantico.com...
> Justin Johnson wrote:
>
> >>Programmers have spent a great deal of time trying to avoid presisly
> >>this sort of problem so I am at a loss as to why you think this would be
> >>useful in anyway.
> >>
> >
> >Ok, imagine I have a class that represents bitmap resources, 3d geometric
> >models or sounds.  These are resources that are allocated externally to
Ruby
> >and are not garbage collected.  Imagine I have written a C/C++ extension
to
> >allow Ruby to request/release such external resources.
> >
> >Perhaps I have a var referencing the resource: myvar =
bitmap("image.tga").
> >Now, when myvar becomes unreferenced, I still have the bitmap image
taking
> >up memory.  This will be the case until garbage collection, whereby
> >finalization can be done and I can release my external bitmap image.  My
> >memory may therefore become full with unused resources that are waiting
for
> >garbage collection to finalize and release them.
> >
> >The problem becomes worse if the resources are allocated via a limited
> >number of handles.  Such as file handles.
> >
> >The ideal would be for finalization to happen as soon an object becomes
> >unreferenced although I can't think of a 100% sure way of achieving that.
> >
> >--
> >Justin Johnson
> >justinj@mobiusent.com
> >Technical Director
> >Mobius
> >
> >
> >
> >
>
> How about a class with the following interface.
>
> x = BitMapLoader.new();
>
> x.loadbitmap("image.tga");
> x.dosomethingwiththedata();
> x.unloadbitmap();
>
> The unloadbitmap method would, back in the C code, unallocate the memory
> used by data and therefore free up the resources. However the referent x
> still has currency with a much smaller footprint and can be GCd later.
>
> I will admit that I do not have any experiance with the Ruby to C
> interface but if you can allocate memory from within the C interface
> then you should be able to unallocate it.
>
> If you can't do this then I can see your problem is somewhat greater
> than I have assumed.
>