/**
* Apply BYSETPOST rules
*
* @access protected
* @param object ilDateList
* @return object ilDateList
*/
protected function applyBYSETPOSRules(ilDateList $list)
{
// return unmodified, if no bysetpos rules are available
if (!$this->recurrence->getBYSETPOSList()) {
return $list;
}
$pos_list = $this->initDateList();
$list->sort();
$candidates = $list->get();
$candidates_count = count($candidates);
foreach ($this->recurrence->getBYSETPOSList() as $position) {
if ($position > 0 and $date = $list->getAtPosition($position)) {
$pos_list->add($date);
}
if ($position < 0 and $date = $list->getAtPosition($candidates_count + $position + 1)) {
$pos_list->add($date);
}
}
return $pos_list;
}
