& DISABLE_WP_CRON ) )
		return;

	if ( false === $crons = _get_cron_array() )
		return;

	$gmt_time = microtime( true );
	$keys = array_keys( $crons );
	if ( isset($keys[0]) && $keys[0] > $gmt_time )
		return;

	$schedules = wp_get_schedules();
	foreach ( $crons as $timestamp => $cronhooks ) {
		if ( $timestamp > $gmt_time ) break;
		foreach ( (array) $cronhooks as $hook => $args ) {
			if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )
				continue;
			spawn_cron( $gmt_time );
			break 2;
		}
	}
}

/**
 * Retrieve supported event recurrence schedules.
 *
 * The default supported recurrences are 'hourly', 'twicedaily', and 'daily'. A plugin may
 * add more by hooking into the {@see 'cron_schedules'} filter. The filter accepts an array
 * of arrays. The outer array has a key that is the name of the schedule or for
 * example 'weekly'. The value is an array with two keys, one is 'interval' and
 * the other is 'display'.
 *
 * The 'interval' is a number in seconds of when the cron job should run. So for
 * 'hourly', the time is 3600 or 60*60. For weekly, the value would be
 * 60*60*24*7 or 604800. The value of 'interval' would then be 604800.
 *
 * The 'display' is the description. For the 'weekly' key, the 'display' would
 * be `__( 'Once Weekly' )`.
 *
 * For your plugin, you will be passed an array. you can easily add your
 * schedule by doing the following.
 *
 *     // Filter parameter variable name is 'array'.
 *     $array['weekly'] = array(
 *         'interval' => 604800,
 *     	   'display'  => __( 'Once Weekly' )
 *     );
 *
 *
 * @since 2.1.0
 *
 * @return array
 */
function wp_get_schedules() {
	$schedules = array(
		'hourly'     => array( 'interval' => HOUR_IN_SECONDS,      'display' => __( 'Once Hourly' ) ),
		'twicedaily' => array( 'interval' => 12 * HOUR_IN_SECONDS, 'display' => __( 'Twice Daily' ) ),
		'daily'      => array( 'interval' => DAY_IN_SECONDS,       'display' => __( 'Once Daily' ) ),
	);
	/**
	 * Filters the non-default cron schedules.
	 *
	 * @since 2.1.0
	 *
	 * @param array $new_schedules An array of non-default cron schedules. Default empty.
	 */
	return array_merge( apply_filters( 'cron_schedules', array() ), $schedules );
}

/**
 * Retrieve the recurrence schedule for an event.
 *
 * @see wp_get_schedules() for available schedules.
 *
 * @since 2.1.0
 *
 * @param string $hook Action hook to identify the event.
 * @param array $args Optional. Arguments passed to the event's callback function.
 * @return string|false False, if no schedule. Schedule name on success.
 */
function wp_get_schedule($hook, $args = array()) {
	$crons = _get_cron_array();
	$key = md5(serialize($args));
	if ( empty($crons) )
		return false;
	foreach ( $crons as $timestamp => $cron ) {
		if ( isset( $cron[$hook][$key] ) )
			return $cron[$hook][$key]['schedule'];
	}
	return false;
}

//
// Private functions
//

/**
 * Retrieve cron info array option.
 *
 * @since 2.1.0
 * @access private
 *
 * @return false|array CRON info array.
 */
function _get_cron_array()  {
	$cron = get_option('cron');
	if ( ! is_array($cron) )
		return false;

	if ( !isset($cron['version']) )
		$cron = _upgrade_cron_array($cron);

	unset($cron['version']);

	return $cron;
}

/**
 * Updates the CRON option with the new CRON array.
 *
 * @since 2.1.0
 * @access private
 *
 * @param array $cron Cron info array from _get_cron_array().
 */
function _set_cron_array($cron) {
	$cron['version'] = 2;
	update_option( 'cron', $cron );
}

/**
 * Upgrade a Cron info array.
 *
 * This function upgrades the Cron info array to version 2.
 *
 * @since 2.1.0
 * @access private
 *
 * @param array $cron Cron info array from _get_cron_array().
 * @return array An upgraded Cron info array.
 */
function _upgrade_cron_array($cron) {
	if ( isset($cron['version']) && 2 == $cron['version'])
		return $cron;

	$new_cron = array();

	foreach ( (array) $cron as $timestamp => $hooks) {
		foreach ( (array) $hooks as $hook => $args ) {
			$key = md5(serialize($args['args']));
			$new_cron[$timestamp][$hook][$key] = $args;
		}
	}

	$new_cron['version'] = 2;
	update_option( 'cron', $new_cron );
	return $new_cron;
}