note 59406 deleted from function.mktime by derick
| From: | derick@php.net | Date: | Sun, 24 Sep 2006 11:51:24 +0000 |
| Subject: | note 59406 deleted from function.mktime by derick | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-117501@lists.php.net to get a copy of this message | ||
Note Submitter: php at cNhOiSpPpAlMe dot org
----
This is an update to my f_IsDstUS() function posted on 22-Apr-2004 05:37.
(http://php.net/manual/en/function.mktime.php#41785)
It now takes account for the Energy Policy Act of 2005 (effective in 2007).
Is it DST in the US on/at $dDate? (Regional exceptions not included.)
Ref.: http://webexhibits.org/daylightsaving/b.html
I use this function to calculate time differences between a server located in the US and a region
not affected by DST, and vice-versa.
<?
function f_IsDstUS ($dDate) {
/* Energy Policy Act of 2005 (effective in 2007) */
$bEnergyPolicyAct2005 = (intval(date("Y",$dDate)) >= 2007);
if ($bEnergyPolicyAct2005) {
/* FROM 2007 */
/* DST START (Second Sunday in March at 2am) */
$dMarch1stDay = mktime(
0,0,0,
3,1,date("Y",$dDate));
$dMarch2ndSunday = $dMarch1stDay
+((7-date("w",$dMarch1stDay))%7+7)*(60*60*24);
$dDstStart = mktime(
2,0,0,
date("m",$dMarch2ndSunday),
date("d",$dMarch2ndSunday),
date("Y",$dMarch2ndSunday));
/* DST END (First Sunday in November at 2am) */
$dNovember1stDay = mktime(
0,0,0,
11,1,date("Y",$dDate));
$dNovember1stSunday = $dNovember1stDay
+((7-date("w",$dNovember1stDay))%7)*(60*60*24);
$dDstEnd = mktime(
2,0,0,
date("m",$dNovember1stSunday),
date("d",$dNovember1stSunday),
date("Y",$dNovember1stSunday));
}
else {
/* BEFORE 2007 */
/* DST START (First Sunday in April at 2am) */
$dApril1stDay = mktime(
0,0,0,
4,1,date("Y",$dDate));
$dApril1stSunday = $dApril1stDay
+((7-date("w",$dApril1stDay))%7)*(60*60*24);
$dDstStart = mktime(
2,0,0,
date("m",$dApril1stSunday),
date("d",$dApril1stSunday),
date("Y",$dApril1stSunday));
/* DST END (Last Sunday in October at 2am) */
$dOctoberLastDay = mktime(
0,0,0,
11,0,date("Y",$dDate));
$dOctoberLastSunday = $dOctoberLastDay
-(date("w",$dOctoberLastDay))*(60*60*24);
$dDstEnd = mktime(
2,0,0,
date("m",$dOctoberLastSunday),
date("d",$dOctoberLastSunday),
date("Y",$dOctoberLastSunday));
}
/* DST INDEX */
return intval( $dDate >= $dDstStart
&& $dDate < $dDstEnd);
}
// Sample usage:
$iHoursToLocal = 15-f_IsDstUS(time());
$dLocal = mktime(
date("H")+$iHoursToLocal,date("i"),date("s"),
date("m"),date("d"),date("Y"));
?>