Problem with strtotime

[Warrigal]

I have a script which calculates how many hours a truck driver has worked/rested in increments of 15 minutes.

 

For a given number of hours I loop around adding 15 minutes to a cursor for each 15 minutes of work/rest.

 

This all works fine until 7 Oct 2012 when adding 15 minutes to 01:45:00 gives a result of 03:00:00 instead of 02:00:00

 

Here's my code:

<?php

$diff = 4; // Number of hours difference in units of 15 minutes
$cursor = "2012-10-07 00:00:00"; // Start time, midnight on 07 October 2012
for($z=0;$z<$diff/.25;$z++) {
	print "Cursor = ".$cursor."<br>";
	$cursor = date('Y-m-d H:i:s', strtotime( "$cursor + 15 minutes" ));
}
?>

This is the result:

 

Cursor = 2012-10-07 00:00:00
Cursor = 2012-10-07 00:15:00
Cursor = 2012-10-07 00:30:00
Cursor = 2012-10-07 00:45:00
Cursor = 2012-10-07 01:00:00
Cursor = 2012-10-07 01:15:00
Cursor = 2012-10-07 01:30:00
Cursor = 2012-10-07 01:45:00 /* Jumps to 03:00:00 instead of 02:00:00 */
Cursor = 2012-10-07 03:00:00
Cursor = 2012-10-07 03:15:00
Cursor = 2012-10-07 03:30:00
Cursor = 2012-10-07 03:45:00
Cursor = 2012-10-07 04:00:00
Cursor = 2012-10-07 04:15:00
Cursor = 2012-10-07 04:30:00
Cursor = 2012-10-07 04:45:00

 

Can anyone help??

[Barand]

try

$dt = new DateTime("2012-10-07 00:00:00");
$di = new DateInterval('PT15M');
$dp = new DatePeriod($dt, $di, 16);

foreach ($dp as $d) {
    echo $d->format('Y-m-d H:i') . '<br>';
}

Output

2012-10-07 00:00
2012-10-07 00:15
2012-10-07 00:30
2012-10-07 00:45
2012-10-07 01:00
2012-10-07 01:15
2012-10-07 01:30
2012-10-07 01:45
2012-10-07 02:00
2012-10-07 02:15
2012-10-07 02:30
2012-10-07 02:45
2012-10-07 03:00
2012-10-07 03:15
2012-10-07 03:30
2012-10-07 03:45
2012-10-07 04:00

[Warrigal]

Thanks Barand!

 

Unfortunately I am using php 5.2.17 and DateInterval was introduced in 5.3 - I will have to update my server and try again.

 

Still curious about the glitch with strtotime though - seems to work with every other date and time except 2012-10-07.

 

[Barand]

Change in daylight saving time

[Barand]

I ran your code for 2013-10-27 (day UK DST changes) and still got

Cursor = 2013-10-27 00:00:00
Cursor = 2013-10-27 00:15:00
Cursor = 2013-10-27 00:30:00
Cursor = 2013-10-27 00:45:00
Cursor = 2013-10-27 01:00:00
Cursor = 2013-10-27 01:15:00
Cursor = 2013-10-27 01:30:00
Cursor = 2013-10-27 01:45:00
Cursor = 2013-10-27 02:00:00
Cursor = 2013-10-27 02:15:00
Cursor = 2013-10-27 02:30:00
Cursor = 2013-10-27 02:45:00
Cursor = 2013-10-27 03:00:00
Cursor = 2013-10-27 03:15:00
Cursor = 2013-10-27 03:30:00
Cursor = 2013-10-27 03:45:00

so that kills the DST theory

[Warrigal]

Problem appears to be fixed in php >=5.3 Thanks for the help!

[Warrigal]

Barand, you were right about DST - this only worked in 5.3 until I set the timezone to Australia/Sydney - DST started on 7th October 2012.

 

It gets handled correctly for all other years that I have tested - I'll dig around some more and let you know.