public void flushBase64() throws java.io.IOException  {
            if( position > 0 ) {
                if( encode ) {
                    out.write( encode3to4( b4, buffer, position, options ) );
                    position = 0;
                }   // end if: encoding
                else {
                    throw new java.io.IOException( "Base64 input not properly padded." );
                }   // end else: decoding
            }   // end if: buffer partially full

        }   // end flush