r->prb_link[0] = p->prb_link[0];
q->prb_link[dir] = r;
r->prb_parent = p->prb_parent;
if (r->prb_link[0] != NULL)
  r->prb_link[0]->prb_parent = r;

t = p->prb_color;
p->prb_color = r->prb_color;
r->prb_color = t;

f = r;
dir = 1;