What can use for DateTime::diff() for PHP 5.2?

Question

Is there any function equivalent to DateTime::diff() in PHP 5.2?

My local server is PHP 5.3 and using DateTime::diff(). then I found that my live site uses PHP 5.2 and gives an error.

Fatal error: Call to undefined method DateTime::diff() in /var/www/some/other/dir/web/daikon/modules/projects/views/admin/log/admin_log_list.php on line 40

The PHP code:

 foreach ($logs as $key => $list){
 ...
 // show date in European way dd-mm-yyyy not in MySQL way yyyy-mm-dd
    $newdate =new DateTime($list['date']) ;
    echo "<td class=\"left\" width=\"8%\">".$newdate->format('d-m-Y')."</td>\n";
    $starttime = new DateTime($list['start_time']);
    echo "<td width=\"7%\">".date_format($starttime, 'H:i')."</td>\n";
    $finishtime = new DateTime($list['finish_time']);
    echo "<td width=\"8%\">".date_format($finishtime, 'H:i')."</td>\n";
    $timediff = 0;
    $interval = $starttime->diff($finishtime);
    $hours   = $interval->format('%h');
    $minutes = $interval->format('%i');
    $timediff = $hours * 60 + $minutes;

Answer 1

I just needed that ( unfortunately ) for a WordPress plugin. This I use the function in 2 times:

1. In my class calling ->diff() ( my class extends DateTime, so $this is the reference DateTime )

   function diff ($secondDate){
       $firstDateTimeStamp = $this->format("U");
       $secondDateTimeStamp = $secondDate->format("U");
       $rv = ($secondDateTimeStamp - $firstDateTimeStamp);
       $di = new DateInterval($rv);
       return $di;
   }
   

2. Then I recreated a fake DateInterval class ( because DateInterval is only valid in PHP >= 5.3 ) as follows:

   Class DateInterval {
       /* Properties */
       public $y = 0;
       public $m = 0;
       public $d = 0;
       public $h = 0;
       public $i = 0;
       public $s = 0;
   
       /* Methods */
       public function __construct ( $time_to_convert /** in seconds */) {
           $FULL_YEAR = 60*60*24*365.25;
           $FULL_MONTH = 60*60*24*(365.25/12);
           $FULL_DAY = 60*60*24;
           $FULL_HOUR = 60*60;
           $FULL_MINUTE = 60;
           $FULL_SECOND = 1;
   
   //        $time_to_convert = 176559;
           $seconds = 0;
           $minutes = 0;
           $hours = 0;
           $days = 0;
           $months = 0;
           $years = 0;
   
           while($time_to_convert >= $FULL_YEAR) {
               $years ++;
               $time_to_convert = $time_to_convert - $FULL_YEAR;
           }
   
           while($time_to_convert >= $FULL_MONTH) {
               $months ++;
               $time_to_convert = $time_to_convert - $FULL_MONTH;
           }
   
           while($time_to_convert >= $FULL_DAY) {
               $days ++;
               $time_to_convert = $time_to_convert - $FULL_DAY;
           }
   
           while($time_to_convert >= $FULL_HOUR) {
               $hours++;
               $time_to_convert = $time_to_convert - $FULL_HOUR;
           }
   
           while($time_to_convert >= $FULL_MINUTE) {
               $minutes++;
               $time_to_convert = $time_to_convert - $FULL_MINUTE;
           }
   
           $seconds = $time_to_convert; // remaining seconds
           $this->y = $years;
           $this->m = $months;
           $this->d = $days;
           $this->h = $hours;
           $this->i = $minutes;
           $this->s = $seconds;
       }
   }
   

Hope that helps somebody.

Answer 2

Please observe that if your DateTime object was created from a date string without any timezone information (as in '2012-01-01 05:00:00' like from mysql), then setting the timezone later with DateTimeZone objects via setTimeZone() does not change the DateTime objects internal timestamp.

$localtime = new DateTime('2012-01-01 08:00:00+02:00'); // Europe/Copenhagen (+ daylight savings)
$localtime->setTimezone(new DateTimeZone('UTC')); // convert local time to utc

$utctime = new DateTime('2012-01-01 06:00:00'); // timezone assumed utc, but is in fact unknown
$utctime->setTimezone(new DateTimeZone('UTC')); // trying to rectify missing timezone which fails, because the internal timestamp isn't modified, although any other format than 'U' may indicate so
#$utctime = new DateTime('2012-01-01 06:00:00+00:00'); // timezone stated, this works

$diff = intval($localtime->format('U')) - intval($utctime->format('U'));
echo $diff; // expecting zero

Answer 3

Here is the best solution for your question.

<?php

/* Find difference between two dates in days. PHP 5.2.x.  */

$d1 = date('Y-m-d', strtotime('2013-06-13'));
$d2 = date("Y-m-d");
echo diff($d1, $d2);

function diff($date1, $date2) {
    $diff = abs(strtotime($date2) - strtotime($date1));
    $years = floor($diff / (365*60*60*24));
    $months = floor(($diff - $years * 365*60*60*24) / (30*60*60*24));
    $days = floor(($diff - $years * 365*60*60*24 - $months*30*60*60*24) / (60*60*24));
    return $days;
}
?>

Answer 4

Read the contrib notes in the PHP date_diff page http://us3.php.net/manual/en/function.date-diff.php