sclass CountingOutputStream extends FilterOutputStream {
  long counter;
  
  *(OutputStream out) { super(out); }
  
  @Override
  public void write(int b) throws IOException {
    ++counter;
    out.write(b);
  }

  @Override
  public void write(byte[] b) throws IOException {
    counter += b.length;
    out.write(b, 0, b.length);
  }

  @Override
  public void write(byte[] b, int off, int len) throws IOException {
    if (len == 0) ret;
    counter += len;
    out.write(b, off, len);
  }
  
  long getFilePointer() { ret counter; }
}