date_parse_from_format in PHP 5.2

I have checked the function I posted from php.net and it didn't work as I expected. I written a new one, which can be extendend. To be more similar to the PHP5.3 one.

if (!function_exists('date_parse_from_format')) {
  function date_parse_from_format($format, $date) {
    $i=0;
    $pos=0;
    $output=array();
    while ($i< strlen($format)) {
      $pat = substr($format, $i, 1);
      $i++;
      switch ($pat) {
        case 'd': //	Day of the month, 2 digits with leading zeros	01 to 31
          $output['day'] = substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'D': // A textual representation of a day: three letters	Mon through Sun
          //TODO
        break;
        case 'j': //	Day of the month without leading zeros	1 to 31
          $output['day'] = substr($date, $pos, 2);
          if (!is_numeric($output['day']) || ($output['day']>31)) {
            $output['day'] = substr($date, $pos, 1);
            $pos--;
          }
          $pos+=2;
        break;
        case 'm': //	Numeric representation of a month: with leading zeros	01 through 12
          $output['month'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'n': //	Numeric representation of a month: without leading zeros	1 through 12
          $output['month'] = substr($date, $pos, 2);
          if (!is_numeric($output['month']) || ($output['month']>12)) {
            $output['month'] = substr($date, $pos, 1);
            $pos--;
          }
          $pos+=2;
        break;
        case 'Y': //	A full numeric representation of a year: 4 digits	Examples: 1999 or 2003
          $output['year'] = (int)substr($date, $pos, 4);
          $pos+=4;
        break;
        case 'y': //	A two digit representation of a year	Examples: 99 or 03
          $output['year'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'g': //	12-hour format of an hour without leading zeros	1 through 12
          $output['hour'] = substr($date, $pos, 2);
          if (!is_numeric($output['day']) || ($output['hour']>12)) {
            $output['hour'] = substr($date, $pos, 1);
            $pos--;
          }
          $pos+=2;
        break;
        case 'G': //	24-hour format of an hour without leading zeros	0 through 23
          $output['hour'] = substr($date, $pos, 2);
          if (!is_numeric($output['day']) || ($output['hour']>23)) {
            $output['hour'] = substr($date, $pos, 1);
            $pos--;
          }
          $pos+=2;
        break;
        case 'h': //	12-hour format of an hour with leading zeros	01 through 12
          $output['hour'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'H': //	24-hour format of an hour with leading zeros	00 through 23
          $output['hour'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'i': //	Minutes with leading zeros	00 to 59
          $output['minute'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 's': //	Seconds: with leading zeros	00 through 59
          $output['second'] = (int)substr($date, $pos, 2);
          $pos+=2;
        break;
        case 'l': // (lowercase 'L')	A full textual representation of the day of the week	Sunday through Saturday
        case 'N': //	ISO-8601 numeric representation of the day of the week (added in PHP 5.1.0)	1 (for Monday) through 7 (for Sunday)
        case 'S': //	English ordinal suffix for the day of the month: 2 characters	st: nd: rd or th. Works well with j
        case 'w': //	Numeric representation of the day of the week	0 (for Sunday) through 6 (for Saturday)
        case 'z': //	The day of the year (starting from 0)	0 through 365
        case 'W': //	ISO-8601 week number of year: weeks starting on Monday (added in PHP 4.1.0)	Example: 42 (the 42nd week in the year)
        case 'F': //	A full textual representation of a month: such as January or March	January through December
        case 'u': //	Microseconds (added in PHP 5.2.2)	Example: 654321
        case 't': //	Number of days in the given month	28 through 31
        case 'L': //	Whether it's a leap year	1 if it is a leap year: 0 otherwise.
        case 'o': //	ISO-8601 year number. This has the same value as Y: except that if the ISO week number (W) belongs to the previous or next year: that year is used instead. (added in PHP 5.1.0)	Examples: 1999 or 2003
        case 'e': //	Timezone identifier (added in PHP 5.1.0)	Examples: UTC: GMT: Atlantic/Azores
        case 'I': // (capital i)	Whether or not the date is in daylight saving time	1 if Daylight Saving Time: 0 otherwise.
        case 'O': //	Difference to Greenwich time (GMT) in hours	Example: +0200
        case 'P': //	Difference to Greenwich time (GMT) with colon between hours and minutes (added in PHP 5.1.3)	Example: +02:00
        case 'T': //	Timezone abbreviation	Examples: EST: MDT ...
        case 'Z': //	Timezone offset in seconds. The offset for timezones west of UTC is always negative: and for those east of UTC is always positive.	-43200 through 50400
        case 'a': //	Lowercase Ante meridiem and Post meridiem	am or pm
        case 'A': //	Uppercase Ante meridiem and Post meridiem	AM or PM
        case 'B': //	Swatch Internet time	000 through 999
        case 'M': //	A short textual representation of a month: three letters	Jan through Dec
        default:
          $pos++;
      }
    }
return  $output;
  }
}