[PATCH] dix: add valuator_mask_fetch_double()

[Peter Hutterer]

On Fri, Sep 30, 2011 at 11:55:35PM +0100, Daniel Stone wrote:
> Hi,
> 
> On 30 September 2011 17:18, Chase Douglas <chase.douglas at canonical.com> wrote:
> > On 09/29/2011 09:29 PM, Peter Hutterer wrote:
> >> Using this call simplifies callers that don't know if the mask bit is set.
> >>
> >> Before:
> >>   if (valuator_mask_isset(mask, valnum))
> >>     value = valuator_mask_get_double(mask, valnum));
> >>   else
> >>     value = someothervalue;
> >>
> >> Now:
> >>  if (!valuator_mask_fetch_double(mask, valnum, &value))
> >>     value = someothervalue;
> >>
> >> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> >
> > I think this will help clean up code all over :).
> >
> > Reviewed-by: Chase Douglas <chase.douglas at canonical.com>
> 
> Yeah, seriously.  Is there any good reason to not make a double which
> returns either 0.0 (if not set) or the mask value (if set) though, on
> the grounds that anyone who wants to know will be using
> isset/get_double?

If I understand this right - I specifically chose not to do this, it allows
for setting value to some (alternative) value and then simply calling fetch,
knowing that the value after fetch will be correct.

in the simplest case:

    int val = dev->last.valuator[0];
    valuator_mask_fetch(mask, 0, &val);

It's not a big difference, I admit, but since 0 can be a valid valuator
value, simply not touching the parameter when we don't know what to set it
to seems the best.

Cheers,
  Peter