Re: [v2 2/3] d3dx9: Use magic number instead of parameter tables for parameter handles.

[Paul Gofman]

I am going to send this patch (along with a few other improvements we 
discussed) at some point. Just if you don't mind I would move straight 
ahead to finalize shared parameters, to make the effect thing finally 
look mostly complete.

On 04/17/2017 11:40 PM, Matteo Bruni wrote:
> 2017-04-14 12:54 GMT+02:00 Paul Gofman :
> > On 04/13/2017 08:55 PM, Matteo Bruni wrote:
> > > 2017-04-11 15:58 GMT+02:00 Paul Gofman :
> > > > Signed-off-by: Paul Gofman 
> > > >    static struct d3dx_parameter *get_valid_parameter(struct
> > > > d3dx9_base_effect *base, D3DXHANDLE parameter)
> > > >    {
> > > > - struct d3dx_parameter **handle_param = (struct d3dx_parameter
> > > >
> > > > **)parameter;
> > > > - struct d3dx_parameter *handle_param = (struct d3dx_parameter
> > > >
> > > > *)parameter;
> > > > - if (handle_param >= base->param_table.table && handle_param <
> > > >
> > > > base->param_table.table + base->param_table.count)
> > > > -
> > > >    return *handle_param;
> > > > - if (handle_param && !strncmp(handle_param->magic_string,
> > > >
> > > > parameter_magic_string,
> > > > -
> > > >        sizeof(parameter_magic_string)))
> > > > -
> > > >    return handle_param;
> > > >
> > > >  return get_parameter_by_name(base, NULL, parameter);
> > > >
> > > > }
> > >
> > > Not new and somewhat separate from the patch, although it gets "more
> > > interesting" with the new handles scheme: we should probably avoid the
> > > call to get_parameter_by_name() if the effect was created with the
> > > D3DXFX_LARGEADDRESSAWARE flag, returning NULL instead. Worth a test I
> > > think.
> >  I did some quick testing of that when D3DXFX_LARGEADDRESSAWARE flag set,
> >
> > what I saw was:
> > - native d3dx crashes on attempt to get or set parameter using name as
> >
> > handle.
> > - when referencing parameter by name in IsParameterUsed, native either crash
> >
> > or returns false.
> >  I guess native behaviour is just to treat handle as parameter pointer
> >
> > when that flag is set, without any checks. I don't achieve a reliable crash
> > on parameter get and even set in our implementation though (possibly due to
> > checks made in typed set's). So I think returning NULL if the magic number
> > does not match as you suggest in this case (i. e. getting a predictable sure
> > crash with null pointer access) is better.
>
> Yes, agreed. Thanks for testing that out.