SimplePie_Parse_Date::date_w3cdtf

	 * @access public
	 * @param string $date Date to parse
	 * @return int Timestamp corresponding to date string, or false on failure
	 */
	public function parse($date)
	{
		foreach ($this->user as $method)
		{
			if (($returned = call_user_func($method, $date)) !== false)
			{
				return $returned;
			}
		}

		foreach ($this->built_in as $method)
		{
			if (($returned = call_user_func(array($this, $method), $date)) !== false)
			{
				return $returned;
			}
		}

		return false;
	}

	/**
	 * Add a callback method to parse a date
	 *
	 * @final
	 * @access public
	 * @param callback $callback
	 */
	public function add_callback($callback)
	{
		if (is_callable($callback))
		{
			$this->user[] = $callback;
		}
		else
		{
			trigger_error('User-supplied function must be a valid callback', E_USER_WARNING);
		}
	}

	/**
	 * Parse a superset of W3C-DTF (allows hyphens and colons to be omitted, as
	 * well as allowing any of upper or lower case "T", horizontal tabs, or
	 * spaces to be used as the time separator (including more than one))
	 *
	 * @access protected
	 * @return int Timestamp
	 */
	public function date_w3cdtf($date)
	{
		static $pcre;
		if (!$pcre)
		{
			$year = '([0-9]{4})';
			$month = $day = $hour = $minute = $second = '([0-9]{2})';
			$decimal = '([0-9]*)';
			$zone = '(?:(Z)|([+\-])([0-9]{1,2}):?([0-9]{1,2}))';
			$pcre = '/^' . $year . '(?:-?' . $month . '(?:-?' . $day . '(?:[Tt\x09\x20]+' . $hour . '(?::?' . $minute . '(?::?' . $second . '(?:.' . $decimal . ')?)?)?' . $zone . ')?)?)?$/';
		}
		if (preg_match($pcre, $date, $match))