private <T extends Collection<E>> T toPlainCollection(T cl) {

      int[] intdata = data;
      for (int bindex = 0; bindex < intdata.length; bindex++) {
        int block = intdata[bindex];
        if (block != 0) {
          int index = bindex << 5; // * 32
          for (int i = 31; i >= 0; i--) {
            if ((block & 1) != 0) {
              cl.add(colValuesInternal.getKey(index));
            }
            index++;
            block >>>= 1;
          }
        }
      }

      return cl;
    }
private <T extends Collection<E>> T toPlainCollection(T cl)