svoid setBit(BitSet b, int bit) {
  b?.set(bit);
}

svoid setBit(BitSet b, int bit, bool value) {
  b?.set(bit, value);
}

svoid setBit(byte[] b, int bit, bool value default true) {
  int idx = bit >> 3;
  byte mask = cast 1 << (bit & 7);
  if (value)
    b[idx] |= mask;
  else
    b[idx] &= ~mask;
}