protected function get_indentation_string( $nr ) {
		if ( 0 >= $nr ) {
			return '';
		}

		// Space-based indentation.
		if ( false === $this->tabIndent ) {
			return str_repeat( ' ', $nr );
		}

		// Tab-based indentation.
		$num_tabs    = (int) floor( $nr / $this->tab_width );
		$remaining   = ( $nr % $this->tab_width );
		$tab_indent  = str_repeat( "\t", $num_tabs );
		$tab_indent .= str_repeat( ' ', $remaining );

		return $tab_indent;
	}