From 412386d975c3c690eaa23bf9541450a842be3fe2 Mon Sep 17 00:00:00 2001
From: Andreas Schwab <schwab@suse.de>
Date: Thu, 21 Jun 2018 16:16:30 +0200
Subject: [PATCH] Avoid undefined behaviour due to division by zero

---
 src/libImaging/QuantOctree.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/libImaging/QuantOctree.c b/src/libImaging/QuantOctree.c
index e18ab3c65..bf53006fe 100644
--- a/src/libImaging/QuantOctree.c
+++ b/src/libImaging/QuantOctree.c
@@ -149,10 +149,17 @@ count_used_color_buckets(const ColorCube cube) {
 static void
 avg_color_from_color_bucket(const ColorBucket bucket, Pixel *dst) {
    float count = bucket->count;
-   dst->c.r = (int)(bucket->r / count);
-   dst->c.g = (int)(bucket->g / count);
-   dst->c.b = (int)(bucket->b / count);
-   dst->c.a = (int)(bucket->a / count);
+   if (bucket->count != 0) {
+       dst->c.r = (int)(bucket->r / count);
+       dst->c.g = (int)(bucket->g / count);
+       dst->c.b = (int)(bucket->b / count);
+       dst->c.a = (int)(bucket->a / count);
+   } else {
+       dst->c.r = 0;
+       dst->c.g = 0;
+       dst->c.b = 0;
+       dst->c.a = 0;
+   }
 }
 
 static int