PHP function that receive a cron string and return the next run timestamp

You could use this class PHP-Parse-cron-strings-and-compute-schedules

It'll also compute the last scheduled run

You can try this: http://mtdowling.com/blog/2012/06/03/cron-expressions-in-php/ which use PHP Cron-Expression parser library, a php class https://github.com/mtdowling/cron-expression

Use this function:

function parse_crontab($time, $crontab)
         {$time=explode(' ', date('i G j n w', strtotime($time)));
          $crontab=explode(' ', $crontab);
          foreach ($crontab as $k=>&$v)
                  {$time[$k]=intval($time[$k]);
                   $v=explode(',', $v);
                   foreach ($v as &$v1)
                           {$v1=preg_replace(array('/^\*$/', '/^\d+$/', '/^(\d+)\-(\d+)$/', '/^\*\/(\d+)$/'),
                                             array('true', $time[$k].'===\0', '(\1<='.$time[$k].' and '.$time[$k].'<=\2)', $time[$k].'%\1===0'),
                                             $v1
                                            );
                           }
                   $v='('.implode(' or ', $v).')';
                  }
          $crontab=implode(' and ', $crontab);
          return eval('return '.$crontab.';');
         }
var_export(parse_crontab('2011-05-04 02:08:03', '*/2,3-5,9 2 3-5 */2 *'));
var_export(parse_crontab('2011-05-04 02:08:03', '*/8 */2 */4 */5 *'));