[FFmpeg-cvslog] swscale: Fix an undefined behaviour

[Luca Barbato]

ffmpeg | branch: release/0.10 | Luca Barbato <lu_zero at gentoo.org> | Fri May  2 00:21:23 2014 +0200| [7fa72700298107fe756311ecb4dee5270ff12d35] | committer: Reinhard Tartler

swscale: Fix an undefined behaviour

Prevent a division by zero down the codepath.

Sample-Id: 00001721-google
Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7fa72700298107fe756311ecb4dee5270ff12d35
---

 libswscale/utils.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index f3a5012..b4a7485 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -269,7 +269,7 @@ static int initFilter(int16_t **outFilter, int32_t **filterPos, int *outFilterSi
 
         xDstInSrc= xInc - 0x10000;
         for (i=0; i<dstW; i++) {
-            int xx= (xDstInSrc - ((filterSize-2)<<16)) / (1<<17);
+            int xx = (xDstInSrc - ((int64_t)(filterSize - 2) << 16)) / (1 << 17);
             int j;
             (*filterPos)[i]= xx;
             for (j=0; j<filterSize; j++) {