return -1;
        if (off < view->off || off + width < view->off + view->width)
                return error("invalid delta: window slides left");
-       if (view->max_off >= 0 && view->max_off < off + width)
+       if (view->max_off >= 0 && view->max_off < off + (off_t) width)
                return error("delta preimage ends early");
 
        file_offset = view->off + view->buf.len;