public void add(Object o) { int n = map.getMappedIndex(o); vector.set(n); }
  public void addAll(OPT_BitSet B) {    if (VM.VerifyAssertions) {      VM.assert(map == B.map);    }    vector.or(B.vector);  }  /**   * Add an object to this bit set.   */  public void add(Object o) {    int n = map.getMappedIndex(o);    vector.set(n);  }