[virt-tools-list] [virt-viewer][PATCH 2/2] coverity: result is not floating-point

[Fabiano Fidencio]

On Mon, Aug 17, 2015 at 6:08 PM, Pavel Grunt <pgrunt at redhat.com> wrote:

> On Mon, 2015-08-17 at 17:55 +0200, Fabiano Fidêncio wrote:
> > Coverity says:
> > Result is not floating-point (UNINTENDED_INTEGER_DIVISION)
> > interger_division: Dividing integer expressions "preferred->width * 100"
> > and "zoom", and then converting the integer quotient to type double. Any
> > remainder, or fractional part of the quotient, is ignored.
>
> I think it is better to remove the round(), otherwise you are changing the
> behavior (which is there since 33614f86db490364339ef69e0eb76f98a4ac8138).
>

I don't see why I am (wrongly) changing the behavior, Pavel.
Can you give me an example?

Nowadays, using the round or not using the round would end up in the same
result and I don't think it's the expected/correct behavior.

Let's consider: width = 640, NORMAL_ZOOM_LEVEL = 100, zoom = 85.

Current behavior:
width = round (640*100/85)
width = round (752)
width = 752.

Removing the round:
width = 640*100/85
width = 752

What I consider the expected behavior:
width = round (640*100/85)
width = round (752.94)
width = 753



> Or is the rounding necessary ?
>

I do think so.


>
> Pavel
> > ---
> >  src/virt-viewer-display.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/virt-viewer-display.c b/src/virt-viewer-display.c
> > index 3efe24c..8431ae4 100644
> > --- a/src/virt-viewer-display.c
> > +++ b/src/virt-viewer-display.c
> > @@ -819,8 +819,8 @@ void
> > virt_viewer_display_get_preferred_monitor_geometry(VirtViewerDisplay*
> self,
> >      if (virt_viewer_display_get_zoom(VIRT_VIEWER_DISPLAY(self))) {
> >          guint zoom =
> > virt_viewer_display_get_zoom_level(VIRT_VIEWER_DISPLAY(self));
> >
> > -        preferred->width = round(preferred->width * NORMAL_ZOOM_LEVEL /
> > zoom);
> > -        preferred->height = round(preferred->height * NORMAL_ZOOM_LEVEL
> /
> > zoom);
> > +        preferred->width = round(preferred->width * NORMAL_ZOOM_LEVEL /
> > (double) zoom);
> > +        preferred->height = round(preferred->height * NORMAL_ZOOM_LEVEL
> /
> > (double) zoom);
> >      }
> >  }
> >
>


Thanks for the review,
-- 
Fabiano Fidêncio
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