sS charIteratorToString_max(CharacterIterator it, int max) {
  if (it == null) null;
  new StringBuilder buf;
  while (max-- > 0 && it.hasNext())
    buf.append(it.next());
  ret str(buf);
}

sS charIteratorToString_max(int max, CharacterIterator it) {
  ret charIteratorToString_max(it, max);
}