private static Pointer _makeIndices(Collection<Integer> indices) {
    if (indices == null || indices.isEmpty()) {
      return null;
    }
    final int step = Native.getNativeSize(Integer.class);
    final Pointer mem = new Pointer(Native.malloc((long)indices.size() * step));
    int offset = 0;
    for (Integer i : indices) {
      mem.setInt(offset, i);
      offset += step;
    }
    return mem;
  }
private static Pointer _makeIndices(Collection<Integer> indices)