PHP date_parse_from_format( ) alternative in PHP 5.2

Question

Since date_parse_from_format( ) is available only in PHP 5.3, I need to write a function that mimics its behaviour in PHP 5.2.

Is it possible to write this function for PHP 5.2 and make it work exactly the same way that it does in PHP 5.3?

Example:

For this input:

<?php
$date = "6.1.2009 13:00+01:00";
print_r(date_parse_from_format("j.n.Y H:iP", $date));
?>

I need this output:

Array
(
    [year] => 2009
    [month] => 1
    [day] => 6
    [hour] => 13
    [minute] => 0
    [second] => 0
    [fraction] => 
    [warning_count] => 0
    [warnings] => Array
        (
        )

    [error_count] => 0
    [errors] => Array
        (
        )

    [is_localtime] => 1
    [zone_type] => 1
    [zone] => -60
    [is_dst] => 
)

Answer 1

<?php
function date_parse_from_format($format, $date) {
  $dMask = array(
    'H'=>'hour',
    'i'=>'minute',
    's'=>'second',
    'y'=>'year',
    'm'=>'month',
    'd'=>'day'
  );
  $format = preg_split('//', $format, -1, PREG_SPLIT_NO_EMPTY); 
  $date = preg_split('//', $date, -1, PREG_SPLIT_NO_EMPTY); 
  foreach ($date as $k => $v) {
    if ($dMask[$format[$k]]) $dt[$dMask[$format[$k]]] .= $v;
  }
  return $dt;
}
?>

Example 1:

<?php
    print_r(date_parse_from_format('mmddyyyy','03232011');
?>

Output 1:

Array ( [month] => 03 [day] => 23 [year] => 2011 )

Example 2:

 <?php
    print_r(date_parse_from_format('yyyy.mm.dd HH:ii:ss','2011.03.23 12:03:00'));
 ?>

Output 2:

Array ( [year] => 2011 [month] => 03 [day] => 23 [hour] => 12 [minute] => 03 [second] => 00 )

Answer 2

Here is my improved version and I think complete. Only errors and warnings are not taken into account.

if( !function_exists('date_parse_from_format') ){
    function date_parse_from_format($format, $date) {
        // reverse engineer date formats
        $keys = array(
            'Y' => array('year', '\d{4}'),              //Année sur 4 chiffres
            'y' => array('year', '\d{2}'),              //Année sur 2 chiffres
            'm' => array('month', '\d{2}'),             //Mois au format numérique, avec zéros initiaux
            'n' => array('month', '\d{1,2}'),           //Mois sans les zéros initiaux
            'M' => array('month', '[A-Z][a-z]{3}'),     //Mois, en trois lettres, en anglais
            'F' => array('month', '[A-Z][a-z]{2,8}'),   //Mois, textuel, version longue; en anglais, comme January ou December
            'd' => array('day', '\d{2}'),               //Jour du mois, sur deux chiffres (avec un zéro initial)
            'j' => array('day', '\d{1,2}'),             //Jour du mois sans les zéros initiaux
            'D' => array('day', '[A-Z][a-z]{2}'),       //Jour de la semaine, en trois lettres (et en anglais)
            'l' => array('day', '[A-Z][a-z]{6,9}'),     //Jour de la semaine, textuel, version longue, en anglais
            'u' => array('hour', '\d{1,6}'),            //Microsecondes
            'h' => array('hour', '\d{2}'),              //Heure, au format 12h, avec les zéros initiaux
            'H' => array('hour', '\d{2}'),              //Heure, au format 24h, avec les zéros initiaux
            'g' => array('hour', '\d{1,2}'),            //Heure, au format 12h, sans les zéros initiaux
            'G' => array('hour', '\d{1,2}'),            //Heure, au format 24h, sans les zéros initiaux
            'i' => array('minute', '\d{2}'),            //Minutes avec les zéros initiaux
            's' => array('second', '\d{2}')             //Secondes, avec zéros initiaux
        );

        // convert format string to regex
        $regex = '';
        $chars = str_split($format);
        foreach ( $chars AS $n => $char ) {
            $lastChar = isset($chars[$n-1]) ? $chars[$n-1] : '';
            $skipCurrent = '\\' == $lastChar;
            if ( !$skipCurrent && isset($keys[$char]) ) {
                $regex .= '(?P<'.$keys[$char][0].'>'.$keys[$char][1].')';
            }
            else if ( '\\' == $char ) {
                $regex .= $char;
            }
            else {
                $regex .= preg_quote($char);
            }
        }

        $dt = array();
        // now try to match it
        if( preg_match('#^'.$regex.'$#', $date, $dt) ){
            foreach ( $dt AS $k => $v ){
                if ( is_int($k) ){
                    unset($dt[$k]);
                }
            }
            if( !checkdate($dt['month'], $dt['day'], $dt['year']) ){
                $dt['error_count'] = 1;
            } else {
                $dt['error_count'] = 0;
            }
        }
        else {
            $dt['error_count'] = 1;
        }

        $dt['errors'] = array();
        $dt['fraction'] = '';
        $dt['warning_count'] = 0;
        $dt['warnings'] = array();
        $dt['is_localtime'] = 0;
        $dt['zone_type'] = 0;
        $dt['zone'] = 0;
        $dt['is_dst'] = '';
        return $dt;
    }
}