private function add_rrule($rrule_string) {
$rules = explode(';', $rrule_string);
$this->recur = TRUE;
if ($this->occurrences === NULL) {
$this->occurrences = Array();
}
// read attributes from rrule_string
$limit_type = '';
$limit = '';
$incrementors = Array(
'SECONDLY' => 'increment_second',
'MINUTELY' => 'increment_minute',
'HOURLY' => 'increment_hour',
'DAILY' => 'increment_day',
'WEEKLY' => 'increment_week',
'MONTHLY' => 'increment_month',
'YEARLY' => 'increment_year',
);
$occurs_by_list = Array();
foreach ($rules as $rule) {
$namevalue = explode('=', $rule);
$rulename = $namevalue[0];
$rulevalue = $namevalue[1];
switch ($rulename) {
case 'FREQ': // always present
$this->incrementor = $incrementors[$rulevalue];
break;
case 'INTERVAL':
$this->interval = $rulevalue;
case 'UNTIL':
$limit_type = 'UNTIL';
$this->until = ICalendar::ical2unix($rulevalue);
break;
case 'COUNT':
$limit_type = 'COUNT';
$limit = $rulevalue;
break;
case (substr($rulename, 0, 2) == 'BY'):
$occurs_by_list[$rulename] = explode(',', $rulevalue);
break;
}
}
// finished reading attributes from rrule_string
$occursByTypes = Array(
'BYMONTH' => Array('func' => 'increment_month', 'format' => 'n'),
'BYWEEKNO' => Array('func' => 'increment_week', 'format' => 'W'),
'BYYEARDAY' => Array('func' => 'increment_day', 'format' => 'z'),
'BYMONTHDAY' => Array('func'=> 'increment_day', 'format' => 'j'),
'BYDAY' => Array('func' => 'increment_day', 'format' => 'w'),
'BYHOUR' => Array('func' => 'increment_hour', 'format' => 'G'),
'BYMINUTE' => Array('func' => 'increment_minute', 'format' => 'i'),
'BYSECOND' => Array('func' => 'increment_second', 'format' => 's'),
);
// create the first occurrence set
$occur_unit = Array($this->range->get_start());
foreach ($occursByTypes as $byfreq => $attribs) {
// we loop through occurByTypes so we can be sure to
// act on each "by frequency" rule in order of decreasing grain size
if (array_key_exists($byfreq, $occurs_by_list)) {
$new_occur_unit = Array();
// every "when" within the "by frequency"
// e.g. MO,TU,WE for BYDAY
// needs to be a separate element of the occurrence set
foreach($occurs_by_list[$byfreq] as $when) {
$occurs_when = ($byfreq == 'BYDAY') ? ICalendar::$dayIndex[$when] : $when;
// if the set of occurrences already has multiple elements
// they will be multiplied
// e.g. MO,TU for BYDAY and 1,2,3 for BYMONTH
// yields 6 elements in the occurence set
foreach ($occur_unit as $start) {
$count = 0; // for debugging below
while (intval(date($attribs['format'], $start)) != $occurs_when) {
$start = call_user_func($attribs['func'], $start);
// haven't seen this happen yet but who knows
if ($count > 366) {
throw new ICalendarException("maximum loop count exceeded");
}
$count += 1;
}
$new_occur_unit[] = $start;
}
}
$occur_unit = $new_occur_unit;
}
}
// BYSETPOS limits us to particular indices of the occurrence set
if (array_key_exists('BYSETPOS', $occurs_by_list)) {
$new_occur_unit = Array();
$setposlist = $occurs_by_list['BYSETPOS'];
foreach ($setposlist as $setpos) {
if ($setpos < 0) {
$setpos = count($occur_unit) + $setpos;
} else {
$setpos = $setpos - 1;
}
$new_occur_unit[] = $occur_unit[$setpos];
}
$occur_unit = $new_occur_unit;
}
$this->occurrences = $occur_unit;
// duplicate the occurrence set for COUNT limits
// this is approximate
if ($limit_type == 'COUNT') {
$num_increments = $limit / count($this_occurrences);
$end = end($occur_unit);
while ($num_increments > 0) {
$end = $this->incrementor($end);
$num_increments -= 1;
}
$this->until = $end;
}
}
