if (p->rtavl_link[0] == NULL)
  {
    if (p->rtavl_rtag == RTAVL_CHILD)
      {
        pa[k - 1]->rtavl_link[da[k - 1]] = p->rtavl_link[1];
      }
    else
      {
        pa[k - 1]->rtavl_link[da[k - 1]] = p->rtavl_link[da[k - 1]];
        if (da[k - 1] == 1)
          pa[k - 1]->rtavl_rtag = RTAVL_THREAD;
      }
  }
else
  {
    struct rtavl_node *r = p->rtavl_link[0];
    if (r->rtavl_rtag == RTAVL_THREAD)
      {
        r->rtavl_link[1] = p->rtavl_link[1];
        r->rtavl_rtag = p->rtavl_rtag;
        r->rtavl_balance = p->rtavl_balance;
        pa[k - 1]->rtavl_link[da[k - 1]] = r;
        da[k] = 0;
        pa[k++] = r;
      }
    else
      {
        struct rtavl_node *s;
        int j = k++;

        for (;;)
          {
            da[k] = 1;
            pa[k++] = r;
            s = r->rtavl_link[1];
            if (s->rtavl_rtag == RTAVL_THREAD)
              break;

            r = s;
          }

        da[j] = 0;
        pa[j] = pa[j - 1]->rtavl_link[da[j - 1]] = s;

        if (s->rtavl_link[0] != NULL)
          r->rtavl_link[1] = s->rtavl_link[0];
        else
          {
            r->rtavl_rtag = RTAVL_THREAD;
            r->rtavl_link[1] = s;
          }

        s->rtavl_balance = p->rtavl_balance;
        s->rtavl_link[0] = p->rtavl_link[0];
        s->rtavl_link[1] = p->rtavl_link[1];
        s->rtavl_rtag = p->rtavl_rtag;
      }
  }

tree->rtavl_alloc->libavl_free (tree->rtavl_alloc, p);