[libchamplain] Catch an arithmetic exception (division by 0)

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit a9ffbb0ed51384ef44886456bc879d01b64702b1
Author: Emmanuel Rodriguez <emmanuel rodriguez booking com>
Date:   Fri Jul 31 20:34:03 2009 +0200

    Catch an arithmetic exception (division by 0)

 tidy/tidy-finger-scroll.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/tidy/tidy-finger-scroll.c b/tidy/tidy-finger-scroll.c
index d404d72..f57f379 100644
--- a/tidy/tidy-finger-scroll.c
+++ b/tidy/tidy-finger-scroll.c
@@ -428,6 +428,18 @@ button_release_event_cb (ClutterActor *actor,
           frac = clutter_qdivx (CLUTTER_FLOAT_TO_FIXED (time_diff/1000.0),
                                 CLUTTER_FLOAT_TO_FIXED (1000.0/60.0));
           
+          /* On a macbook that's running Ubuntu 9.04 sometimes frac is 0 and
+             this causes a division by 0. Here we try to avoid that.
+           */
+          if (frac == 0)
+            {
+                g_print ("Caught a division by 0 (%d / %d).\n",
+                    CLUTTER_FLOAT_TO_FIXED (time_diff/1000.0),
+                    CLUTTER_FLOAT_TO_FIXED (1000.0/60.0)
+                );
+                clutter_event_put ((ClutterEvent *)event);
+                return TRUE;
+            }
           /* See how many units to move in 1/60th of a second */
           priv->dx = CLUTTER_UNITS_FROM_FIXED(clutter_qdivx (
                      CLUTTER_UNITS_TO_FIXED(x_origin - x), frac));