docs: public void growMaxColumns( int desiredColumns , boolean preserveValue ) {
          if( col_idx.length < desiredColumns+1 ) {
              int[] c = new int[ desiredColumns+1 ];
              if( preserveValue )
                  System.arraycopy(col_idx,0,c,0,col_idx.length);
              col_idx = c;
          }
      }