Use / and % operators instead of reimplementing them with a loop.

Originally committed as revision 18597 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/xan.c

@@ -351,16 +351,8 @@ static void xan_wc3_decode_frame(XanContext *s) {
 
         /* coordinate accounting */
         total_pixels -= size;
-        while (size) {
+        y += (x + size) / width;
-            if (x + size >= width) {
+        x  = (x + size) % width;
-                y++;
-                size -= (width - x);
-                x = 0;
-            } else {
-                x += size;
-                size = 0;
-            }
-        }
     }
 }