code: public boolean containsAll(IntBitSet set) {
          int i, end;
  
          if (data.length < set.data.length) {
              end = data.length;
              for (i = end; i < set.data.length; i++) {
                  if (set.data[i] != 0) {
                      return false;
                  }
              }
          } else {
              end = set.data.length;
          }
  
          for (i = 0; i < end; i++) {
              // any bits in set where this has none?  -> false
              if ((set.data[i] & ~data[i])!= 0) {
                  return false;
              }
          }
          return true;
      }
docs: The subset test.
  @param   set  the set to be compared with
  @return  true, if the argument is contained