WooYun.org

// --------------------------------------------------------------------
	/**
	 * ORDER BY
	 *
	 * @param	string	$orderby
	 * @param	string	$direction	ASC, DESC or RANDOM
	 * @param	bool	$escape
	 * @return	CI_DB_query_builder
	 */
	public function order_by($orderby, $direction = '', $escape = NULL)
	{
		$direction = strtoupper(trim($direction));
		if ($direction === 'RANDOM')
		{
			$direction = '';
			// Do we have a seed value?
			$orderby = ctype_digit((string) $orderby)
				? sprintf($this->_random_keyword[1], $orderby)
				: $this->_random_keyword[0];
		}
		elseif (empty($orderby))
		{
			return $this;
		}
		elseif ($direction !== '')
		{
			$direction = in_array($direction, array('ASC', 'DESC'), TRUE) ? ' '.$direction : '';
		}
		is_bool($escape) OR $escape = $this->_protect_identifiers;
		if ($escape === FALSE)
		{
			$qb_orderby[] = array('field' => $orderby, 'direction' => $direction, 'escape' => FALSE);
		}
		else
		{
			$qb_orderby = array();
			foreach (explode(',', $orderby) as $field)
			{
				$qb_orderby[] = ($direction === '' && preg_match('/\s+(ASC|DESC)$/i', rtrim($field), $match, PREG_OFFSET_CAPTURE))
					? array('field' => ltrim(substr($field, 0, $match[0][1])), 'direction' => ' '.$match[1][0], 'escape' => TRUE)
					: array('field' => trim($field), 'direction' => $direction, 'escape' => TRUE);
			}
		}
		$this->qb_orderby = array_merge($this->qb_orderby, $qb_orderby);
		if ($this->qb_caching === TRUE)
		{
			$this->qb_cache_orderby = array_merge($this->qb_cache_orderby, $qb_orderby);
			$this->qb_cache_exists[] = 'orderby';
		}
		return $this;
	}