--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/sabre/vobject/lib/Recur/EventIterator.php	Sat Jan 13 09:06:10 2018 -0500
@@ -0,0 +1,497 @@
+<?php
+
+namespace Sabre\VObject\Recur;
+
+use InvalidArgumentException;
+use DateTime;
+use DateTimeZone;
+use Sabre\VObject\Component;
+use Sabre\VObject\Component\VEvent;
+
+/**
+ * This class is used to determine new for a recurring event, when the next
+ * events occur.
+ *
+ * This iterator may loop infinitely in the future, therefore it is important
+ * that if you use this class, you set hard limits for the amount of iterations
+ * you want to handle.
+ *
+ * Note that currently there is not full support for the entire iCalendar
+ * specification, as it's very complex and contains a lot of permutations
+ * that's not yet used very often in software.
+ *
+ * For the focus has been on features as they actually appear in Calendaring
+ * software, but this may well get expanded as needed / on demand
+ *
+ * The following RRULE properties are supported
+ *   * UNTIL
+ *   * INTERVAL
+ *   * COUNT
+ *   * FREQ=DAILY
+ *     * BYDAY
+ *     * BYHOUR
+ *     * BYMONTH
+ *   * FREQ=WEEKLY
+ *     * BYDAY
+ *     * BYHOUR
+ *     * WKST
+ *   * FREQ=MONTHLY
+ *     * BYMONTHDAY
+ *     * BYDAY
+ *     * BYSETPOS
+ *   * FREQ=YEARLY
+ *     * BYMONTH
+ *     * BYMONTHDAY (only if BYMONTH is also set)
+ *     * BYDAY (only if BYMONTH is also set)
+ *
+ * Anything beyond this is 'undefined', which means that it may get ignored, or
+ * you may get unexpected results. The effect is that in some applications the
+ * specified recurrence may look incorrect, or is missing.
+ *
+ * The recurrence iterator also does not yet support THISANDFUTURE.
+ *
+ * @copyright Copyright (C) 2011-2015 fruux GmbH (https://fruux.com/).
+ * @author Evert Pot (http://evertpot.com/)
+ * @license http://sabre.io/license/ Modified BSD License
+ */
+class EventIterator implements \Iterator {
+
+    /**
+     * Reference timeZone for floating dates and times.
+     *
+     * @var DateTimeZone
+     */
+    protected $timeZone;
+
+    /**
+     * True if we're iterating an all-day event.
+     *
+     * @var bool
+     */
+    protected $allDay = false;
+
+    /**
+     * Creates the iterator
+     *
+     * You should pass a VCALENDAR component, as well as the UID of the event
+     * we're going to traverse.
+     *
+     * @param Component $vcal
+     * @param string|null $uid
+     * @param DateTimeZone $timeZone Reference timezone for floating dates and
+     *                               times.
+     */
+    public function __construct(Component $vcal, $uid = null, DateTimeZone $timeZone = null) {
+
+        if (is_null($this->timeZone)) {
+            $timeZone = new DateTimeZone('UTC');
+        }
+        $this->timeZone = $timeZone;
+
+        if ($vcal instanceof VEvent) {
+            // Single instance mode.
+            $events = array($vcal);
+        } else {
+            $uid = (string)$uid;
+            if (!$uid) {
+                throw new InvalidArgumentException('The UID argument is required when a VCALENDAR is passed to this constructor');
+            }
+            if (!isset($vcal->VEVENT)) {
+                throw new InvalidArgumentException('No events found in this calendar');
+            }
+            $events = array();
+            foreach($vcal->VEVENT as $event) {
+                if ($event->uid->getValue() === $uid) {
+                    $events[] = $event;
+                }
+            }
+
+        }
+
+        foreach($events as $vevent) {
+
+            if (!isset($vevent->{'RECURRENCE-ID'})) {
+
+                $this->masterEvent = $vevent;
+
+            } else {
+
+                $this->exceptions[
+                    $vevent->{'RECURRENCE-ID'}->getDateTime($this->timeZone)->getTimeStamp()
+                ] = true;
+                $this->overriddenEvents[] = $vevent;
+
+            }
+
+        }
+
+        if (!$this->masterEvent) {
+            // No base event was found. CalDAV does allow cases where only
+            // overridden instances are stored.
+            //
+            // In this particular case, we're just going to grab the first
+            // event and use that instead. This may not always give the
+            // desired result.
+            if (!count($this->overriddenEvents)) {
+                throw new InvalidArgumentException('This VCALENDAR did not have an event with UID: ' . $uid);
+            }
+            $this->masterEvent = array_shift($this->overriddenEvents);
+        }
+
+        $this->startDate = $this->masterEvent->DTSTART->getDateTime($this->timeZone);
+        $this->allDay = !$this->masterEvent->DTSTART->hasTime();
+
+        if (isset($this->masterEvent->EXDATE)) {
+
+            foreach($this->masterEvent->EXDATE as $exDate) {
+
+                foreach($exDate->getDateTimes($this->timeZone) as $dt) {
+                    $this->exceptions[$dt->getTimeStamp()] = true;
+                }
+
+            }
+
+        }
+
+        if (isset($this->masterEvent->DTEND)) {
+            $this->eventDuration =
+                $this->masterEvent->DTEND->getDateTime($this->timeZone)->getTimeStamp() -
+                $this->startDate->getTimeStamp();
+        } elseif (isset($this->masterEvent->DURATION)) {
+            $duration = $this->masterEvent->DURATION->getDateInterval();
+            $end = clone $this->startDate;
+            $end->add($duration);
+            $this->eventDuration = $end->getTimeStamp() - $this->startDate->getTimeStamp();
+        } elseif ($this->allDay) {
+            $this->eventDuration = 3600 * 24;
+        } else {
+            $this->eventDuration = 0;
+        }
+
+        if (isset($this->masterEvent->RDATE)) {
+            $this->recurIterator = new RDateIterator(
+                $this->masterEvent->RDATE->getParts(),
+                $this->startDate
+            );
+        } elseif (isset($this->masterEvent->RRULE)) {
+            $this->recurIterator = new RRuleIterator(
+                $this->masterEvent->RRULE->getParts(),
+                $this->startDate
+            );
+        } else {
+            $this->recurIterator = new RRuleIterator(
+                array(
+                    'FREQ' => 'DAILY',
+                    'COUNT' => 1,
+                ),
+                $this->startDate
+            );
+        }
+
+        $this->rewind();
+        if (!$this->valid()) {
+            throw new NoInstancesException('This recurrence rule does not generate any valid instances');
+        }
+
+    }
+
+    /**
+     * Returns the date for the current position of the iterator.
+     *
+     * @return DateTime
+     */
+    public function current() {
+
+        if ($this->currentDate) {
+            return clone $this->currentDate;
+        }
+
+    }
+
+    /**
+     * This method returns the start date for the current iteration of the
+     * event.
+     *
+     * @return DateTime
+     */
+    public function getDtStart() {
+
+        if ($this->currentDate) {
+            return clone $this->currentDate;
+        }
+
+    }
+
+    /**
+     * This method returns the end date for the current iteration of the
+     * event.
+     *
+     * @return DateTime
+     */
+    public function getDtEnd() {
+
+        if (!$this->valid()) {
+            return null;
+        }
+        $end = clone $this->currentDate;
+        $end->modify('+' . $this->eventDuration . ' seconds');
+        return $end;
+
+    }
+
+    /**
+     * Returns a VEVENT for the current iterations of the event.
+     *
+     * This VEVENT will have a recurrence id, and it's DTSTART and DTEND
+     * altered.
+     *
+     * @return VEvent
+     */
+    public function getEventObject() {
+
+        if ($this->currentOverriddenEvent) {
+            return $this->currentOverriddenEvent;
+        }
+
+        $event = clone $this->masterEvent;
+
+        // Ignoring the following block, because PHPUnit's code coverage
+        // ignores most of these lines, and this messes with our stats.
+        //
+        // @codeCoverageIgnoreStart
+        unset(
+            $event->RRULE,
+            $event->EXDATE,
+            $event->RDATE,
+            $event->EXRULE,
+            $event->{'RECURRENCE-ID'}
+        );
+        // @codeCoverageIgnoreEnd
+
+        $event->DTSTART->setDateTime($this->getDtStart());
+        if (isset($event->DTEND)) {
+            $event->DTEND->setDateTime($this->getDtEnd());
+        }
+        // Including a RECURRENCE-ID to the object, unless this is the first
+        // object.
+        //
+        // The inner recurIterator is always one step ahead, this is why we're
+        // checking for the key being higher than 1.
+        if ($this->recurIterator->key() > 1) {
+            $recurid = clone $event->DTSTART;
+            $recurid->name = 'RECURRENCE-ID';
+            $event->add($recurid);
+        }
+        return $event;
+
+    }
+
+    /**
+     * Returns the current position of the iterator.
+     *
+     * This is for us simply a 0-based index.
+     *
+     * @return int
+     */
+    public function key() {
+
+        // The counter is always 1 ahead.
+        return $this->counter - 1;
+
+    }
+
+    /**
+     * This is called after next, to see if the iterator is still at a valid
+     * position, or if it's at the end.
+     *
+     * @return bool
+     */
+    public function valid() {
+
+        return !!$this->currentDate;
+
+    }
+
+    /**
+     * Sets the iterator back to the starting point.
+     */
+    public function rewind() {
+
+        $this->recurIterator->rewind();
+        // re-creating overridden event index.
+        $index = array();
+        foreach($this->overriddenEvents as $key=>$event) {
+            $stamp = $event->DTSTART->getDateTime($this->timeZone)->getTimeStamp();
+            $index[$stamp] = $key;
+        }
+        krsort($index);
+        $this->counter = 0;
+        $this->overriddenEventsIndex = $index;
+        $this->currentOverriddenEvent = null;
+
+        $this->nextDate = null;
+        $this->currentDate = clone $this->startDate;
+
+        $this->next();
+
+    }
+
+    /**
+     * Advances the iterator with one step.
+     *
+     * @return void
+     */
+    public function next() {
+
+        $this->currentOverriddenEvent = null;
+        $this->counter++;
+        if ($this->nextDate) {
+            // We had a stored value.
+            $nextDate = $this->nextDate;
+            $this->nextDate = null;
+        } else {
+            // We need to ask rruleparser for the next date.
+            // We need to do this until we find a date that's not in the
+            // exception list.
+            do {
+                if (!$this->recurIterator->valid()) {
+                    $nextDate = null;
+                    break;
+                }
+                $nextDate = $this->recurIterator->current();
+                $this->recurIterator->next();
+            } while(isset($this->exceptions[$nextDate->getTimeStamp()]));
+
+        }
+
+
+        // $nextDate now contains what rrule thinks is the next one, but an
+        // overridden event may cut ahead.
+        if ($this->overriddenEventsIndex) {
+
+            $offset = end($this->overriddenEventsIndex);
+            $timestamp = key($this->overriddenEventsIndex);
+            if (!$nextDate || $timestamp < $nextDate->getTimeStamp()) {
+                // Overridden event comes first.
+                $this->currentOverriddenEvent = $this->overriddenEvents[$offset];
+
+                // Putting the rrule next date aside.
+                $this->nextDate = $nextDate;
+                $this->currentDate = $this->currentOverriddenEvent->DTSTART->getDateTime($this->timeZone);
+
+                // Ensuring that this item will only be used once.
+                array_pop($this->overriddenEventsIndex);
+
+                // Exit point!
+                return;
+
+            }
+
+        }
+
+        $this->currentDate = $nextDate;
+
+    }
+
+    /**
+     * Quickly jump to a date in the future.
+     *
+     * @param DateTime $dateTime
+     */
+    public function fastForward(DateTime $dateTime) {
+
+        while($this->valid() && $this->getDtEnd() < $dateTime ) {
+            $this->next();
+        }
+
+    }
+
+    /**
+     * Returns true if this recurring event never ends.
+     *
+     * @return bool
+     */
+    public function isInfinite() {
+
+        return $this->recurIterator->isInfinite();
+
+    }
+
+    /**
+     * RRULE parser
+     *
+     * @var RRuleIterator
+     */
+    protected $recurIterator;
+
+    /**
+     * The duration, in seconds, of the master event.
+     *
+     * We use this to calculate the DTEND for subsequent events.
+     */
+    protected $eventDuration;
+
+    /**
+     * A reference to the main (master) event.
+     *
+     * @var VEVENT
+     */
+    protected $masterEvent;
+
+    /**
+     * List of overridden events.
+     *
+     * @var array
+     */
+    protected $overriddenEvents = array();
+
+    /**
+     * Overridden event index.
+     *
+     * Key is timestamp, value is the index of the item in the $overriddenEvent
+     * property.
+     *
+     * @var array
+     */
+    protected $overriddenEventsIndex;
+
+    /**
+     * A list of recurrence-id's that are either part of EXDATE, or are
+     * overridden.
+     *
+     * @var array
+     */
+    protected $exceptions = array();
+
+    /**
+     * Internal event counter
+     *
+     * @var int
+     */
+    protected $counter;
+
+    /**
+     * The very start of the iteration process.
+     *
+     * @var DateTime
+     */
+    protected $startDate;
+
+    /**
+     * Where we are currently in the iteration process
+     *
+     * @var DateTime
+     */
+    protected $currentDate;
+
+    /**
+     * The next date from the rrule parser.
+     *
+     * Sometimes we need to temporary store the next date, because an
+     * overridden event came before.
+     *
+     * @var DateTime
+     */
+    protected $nextDate;
+
+}