mdeg_diff_t
bzero(&(res->added), sizeof (mdeg_diff_t));
bzero(&(res->removed), sizeof (mdeg_diff_t));
bzero(&(res->match_prev), sizeof (mdeg_diff_t));
bzero(&(res->match_curr), sizeof (mdeg_diff_t));
mdeg_diff_t added;
mdeg_diff_t removed;
mdeg_diff_t match_curr;
mdeg_diff_t match_prev;