struct rtrb_node *w = pa[k - 1]->rtrb_link[0];

if (w->rtrb_color == RTRB_RED)
  {
    w->rtrb_color = RTRB_BLACK;
    pa[k - 1]->rtrb_color = RTRB_RED;

    pa[k - 1]->rtrb_link[0] = w->rtrb_link[1];
    w->rtrb_link[1] = pa[k - 1];
    pa[k - 2]->rtrb_link[da[k - 2]] = w;

    pa[k] = pa[k - 1];
    da[k] = 1;
    pa[k - 1] = w;
    k++;

    w = pa[k - 1]->rtrb_link[0];
  }

if ((w->rtrb_link[0] == NULL
     || w->rtrb_link[0]->rtrb_color == RTRB_BLACK)
    && (w->rtrb_rtag == RTRB_THREAD
        || w->rtrb_link[1]->rtrb_color == RTRB_BLACK))
  {
    w->rtrb_color = RTRB_RED;
  }
else
  {
    if (w->rtrb_link[0] == NULL
        || w->rtrb_link[0]->rtrb_color == RTRB_BLACK)
      {
        struct rtrb_node *y = w->rtrb_link[1];
        y->rtrb_color = RTRB_BLACK;
        w->rtrb_color = RTRB_RED;
        w->rtrb_link[1] = y->rtrb_link[0];
        y->rtrb_link[0] = w;
        w = pa[k - 1]->rtrb_link[0] = y;

        if (w->rtrb_link[0]->rtrb_link[1] == NULL)
          {
            w->rtrb_link[0]->rtrb_rtag = RTRB_THREAD;
            w->rtrb_link[0]->rtrb_link[1] = w;
          }
      }

    w->rtrb_color = pa[k - 1]->rtrb_color;
    pa[k - 1]->rtrb_color = RTRB_BLACK;
    w->rtrb_link[0]->rtrb_color = RTRB_BLACK;

    pa[k - 1]->rtrb_link[0] = w->rtrb_link[1];
    w->rtrb_link[1] = pa[k - 1];
    pa[k - 2]->rtrb_link[da[k - 2]] = w;

    if (w->rtrb_rtag == RTRB_THREAD)
      {
        w->rtrb_rtag = RTRB_CHILD;
        pa[k - 1]->rtrb_link[0] = NULL;
      }
    break;
  }