/**
* special method to build events taking place relative to easter
*
* @param Tx_CzSimpleCal_Utility_DateTime $start
* @param Tx_CzSimpleCal_Utility_DateTime $end
* @param Tx_CzSimpleCal_Utility_DateTime $until
* @see http://de.php.net/manual/en/function.easter-days.php
*/
protected function buildEaster($start, $end, $until)
{
if (!function_exists('easter_days') || !function_exists('easter_date')) {
throw new RuntimeException('The function easter_days() or easter_date() is not available in your PHP installation.
The binaries were probably not compiled using --enable-calendar. Contact your
server administrator to fix this.');
}
/**
* calculate the day offset
*/
/**
* the day of the year of the date given as start
* 0 is the 1st January
*
* @var integer
*/
$dayOfYear = date('z', $start->getTimestamp());
$year = date('Y', $start->getTimestamp());
$dayOfYearEaster = $this->getDayOfYearForEasterSunday($year);
/**
* a string for DateTime->modify() to jump from easter sunday
* to the desired date
* null if no jumping required
*
* @var string|null
*/
$diffDaysStart = $dayOfYear - $dayOfYearEaster;
$diffDaysStart = sprintf('%+d days', $diffDaysStart);
/**
* a string for DateTime->modify() to jump from easter sunday
* to the desired date
* null if no jumping required
*
* @var string|null
*/
$diffDaysEnd = date('z', $end->getTimestamp()) - $dayOfYearEaster;
$diffDaysEnd = sprintf('%+d days', $diffDaysEnd);
while ($until >= $start) {
$this->timeline->add(array('start' => $start->getTimestamp(), 'end' => $end->getTimestamp()));
// calculate dates for the next year
$year = $year + 1;
/**
* timestamp for easter sunday of a given year
* @var integer
*/
$easter = easter_date($year);
$start->setDate($year, date('n', $easter), date('j', $easter));
if (!is_null($diffDaysStart)) {
$start->modify($diffDaysStart);
}
$end->setDate($year, date('n', $easter), date('j', $easter));
if (!is_null($diffDaysEnd)) {
$end->modify($diffDaysEnd);
}
}
}
