// little-endian
sclass BitBuffer {
  new ByteBuffer byteBuffer; // TODO (optimization): use a growing circular buffer
  int currentByte, currentBit;
  
  void add(bool b) {
    if (b) currentByte ||= 1 << currentBit;
    if (currentBit == 7) {
      byteBuffer.add((byte) currentByte);
      currentByte = 0;
      currentBit = 0;
    } else
      ++currentBit;
  }
  
  bool hasFullByte() {
    ret !byteBuffer.isEmpty();
  }
  
  byte popFullByte() {
    ret byteBuffer.popFirst();
  }

  // TODO: optimize void writeBits(int data, int nBits)
}