// little-endian
persistable sclass BitBuffer is IntSize {
  new ByteBuffer byteBuffer; // TODO (optimization): use a growing circular buffer
  int currentByte, currentBit;
  
  void add(int b) {
    add(odd(b));
  }
  
  void add(bool b) {
    if (b) currentByte |= 1 << currentBit;
    if (currentBit == 7) {
      byteBuffer.add((byte) currentByte);
      currentByte = 0;
      currentBit = 0;
    } else
      ++currentBit;
  }
  
  bool get(int iBit) {
    int iByte = iBit >> 3;
    int theByte = iByte == byteBuffer.size()
      ? currentByte 
      : byteBuffer.get(iByte);
    ret (theByte & (1 << (iBit & 7))) != 0;
  }
  
  bool hasFullByte() {
    ret !byteBuffer.isEmpty();
  }
  
  byte popFullByte() {
    ret byteBuffer.popFirst();
  }
  
  public int size() {
    ret byteBuffer.size()*8 + currentBit;
  }
  
  // TODO: optimize void writeBits(int data, int nBits)
}

Began life as a copy of #1033633