Check of count or size is 0 in heapsort

src/heapsort.c

@@ -29,9 +29,17 @@ void
 uc_heapsort(void *base_, size_t count, size_t width,
      uc_hs_cmp cmp, uc_hs_swp swap, void *cookie)
 {
-    int start = count / 2 - 1, end = count - 1;
+    long start;
+    long end;
     unsigned char *base = base_;
 
+    if (count == 0 || width == 0) {
+        return;
+    }
+
+    start = count / 2 - 1, 
+    end = count - 1;
+
     while (start >= 0) {
         uc_sift(base, start, count, width, cmp, swap, cookie);
         start--;