note 34916 added to function.date
| From: | michael at michaelthompson dot org | Date: | Mon, 11 Aug 2003 21:20:57 +0000 |
| Subject: | note 34916 added to function.date | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-53911@lists.php.net to get a copy of this message | ||
I needed to be able to calculate Easter
# based on the C implementation at
# http://www.ely.anglican.org/etc/easter2.c
# of the algorithm found here
# http://www.oremus.org/liturgy/etc/ktf/app/easter.html
function Easter($year)
{
$golden = ($year % 19) + 1;
# Gregorian calendar
$dom = ($year + ($year/4) - ($year/100) + ($year/400)) % 7;
if( $dom<0 ) $dom += 7;
$solar = floor(($year - 1600)/100 - ($year - 1600)/400);
$lunar = floor(((($year - 1400)/100) * 8) /25);
$pfm = floor((3 - (11 * $golden) + $solar - $lunar) % 30);
if( $pfm<0 ) $pfm += 30;
if( ($pfm==29) || ($pfm==28 && $golden>11) )
$pfm--;
$tmp = floor((4 - $pfm - $dom) % 7);
if( $tmp<0 ) $tmp += 7;
#$easter = $pfm + $tmp + 1;
# for some reason the php implementation
# of the algorithm was off by one day in years
# evenly divisible by 4 ??? could there be a bug
# in mktime?
$easter = $pfm + $tmp + ((fmod($year,4)==0)?0:1);
if( $easter<11 )
{
$mo = 3;
$da = $easter + 21;
}
else
{
$mo = 4;
$da = $easter - 10;
}
$rtn = mktime(0,0,0,$mo,$da,$year);
return $rtn;
}
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Manual Page -- http://www.php.net/manual/en/function.date.php
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