summaryrefslogtreecommitdiffstats
path: root/kalarm/karecurrence.cpp
blob: b6051ca3cc05572ce609a219f15c3f728ae657a2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
/*
 *  karecurrence.cpp  -  recurrence with special yearly February 29th handling
 *  Program:  kalarm
 *  Copyright © 2005,2006,2008 by David Jarvie <djarvie@kde.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "kalarm.h"

#include <tqbitarray.h>
#include <kdebug.h>

#include <libkcal/icalformat.h>

#include "datetime.h"
#include "functions.h"
#include "karecurrence.h"

using namespace KCal;

/*=============================================================================
= Class KARecurrence
= The purpose of this class is to represent the restricted range of recurrence
= types which are handled by KAlarm, and to translate between these and the
= libkcal Recurrence class. In particular, it handles yearly recurrences on
= 29th February specially:
=
= KARecurrence allows annual 29th February recurrences to fall on 28th
= February or 1st March, or not at all, in non-leap years. It allows such
= 29th February recurrences to be combined with the 29th of other months in
= a simple way, represented simply as the 29th of multiple months including
= February. For storage in the libkcal calendar, the 29th day of the month
= recurrence for other months is combined with a last-day-of-February or a
= 60th-day-of-the-year recurrence rule, thereby conforming to RFC2445.
=============================================================================*/


KARecurrence::Feb29Type KARecurrence::mDefaultFeb29 = KARecurrence::FEB29_FEB29;


/******************************************************************************
*  Set up a KARecurrence from recurrence parameters, using the start date to
*  determine the recurrence day/month as appropriate.
*  Only a restricted subset of recurrence types is allowed.
*  Reply = true if successful.
*/
bool KARecurrence::set(Type recurType, int freq, int count, int f29, const DateTime& start, const TQDateTime& end)
{
	mCachedType = -1;
	RecurrenceRule::PeriodType rrtype;
	switch (recurType)
	{
		case MINUTELY:    rrtype = RecurrenceRule::rMinutely;  break;
		case DAILY:       rrtype = RecurrenceRule::rDaily;  break;
		case WEEKLY:      rrtype = RecurrenceRule::rWeekly;  break;
		case MONTHLY_DAY: rrtype = RecurrenceRule::rMonthly;  break;
		case ANNUAL_DATE: rrtype = RecurrenceRule::rYearly;  break;
		case NO_RECUR:    rrtype = RecurrenceRule::rNone;  break;
		default:
			return false;
	}
	if (!init(rrtype, freq, count, f29, start, end))
		return false;
	switch (recurType)
	{
		case WEEKLY:
		{
			TQBitArray days(7);
			days.setBit(start.date().dayOfWeek() - 1);
			addWeeklyDays(days);
			break;
		}
		case MONTHLY_DAY:
			addMonthlyDate(start.date().day());
			break;
		case ANNUAL_DATE:
			addYearlyDate(start.date().day());
			addYearlyMonth(start.date().month());
			break;
		default:
			break;
	}
	return true;
}

/******************************************************************************
*  Initialise a KARecurrence from recurrence parameters.
*  Reply = true if successful.
*/
bool KARecurrence::init(RecurrenceRule::PeriodType recurType, int freq, int count, int f29, const DateTime& start,
                        const TQDateTime& end)
{
	mCachedType = -1;
	Feb29Type feb29Type = (f29 == -1) ? mDefaultFeb29 : static_cast<Feb29Type>(f29);
	mFeb29Type = FEB29_FEB29;
	clear();
	if (count < -1)
		return false;
	bool dateOnly = start.isDateOnly();
	if (!count  &&  ((!dateOnly && !end.isValid())
	              || (dateOnly && !end.date().isValid())))
		return false;
	switch (recurType)
	{
		case RecurrenceRule::rMinutely:
		case RecurrenceRule::rDaily:
		case RecurrenceRule::rWeekly:
		case RecurrenceRule::rMonthly:
		case RecurrenceRule::rYearly:
			break;
		case rNone:
			return true;
		default:
			return false;
	}
	setNewRecurrenceType(recurType, freq);
	if (count)
		setDuration(count);
	else if (dateOnly)
		setEndDate(end.date());
	else
		setEndDateTime(end);
	TQDateTime startdt = start.dateTime();
	if ((recurType == RecurrenceRule::rYearly
	&&  feb29Type == FEB29_FEB28) || feb29Type == FEB29_MAR1)
	{
		int year = startdt.date().year();
		if (!TQDate::leapYear(year)
		&&  startdt.date().dayOfYear() == (feb29Type == FEB29_MAR1 ? 60 : 59))
		{
			/* The event start date is February 28th or March 1st, but it
			 * is a recurrence on February 29th (recurring on February 28th
			 * or March 1st in non-leap years). Adjust the start date to
			 * be on February 29th in the last previous leap year.
			 * This is necessary because KARecurrence represents all types
			 * of 29th February recurrences by a simple 29th February.
			 */
			while (!TQDate::leapYear(--year)) ;
			startdt.setDate(TQDate(year, 2, 29));
		}
		mFeb29Type = feb29Type;
	}
	if (dateOnly)
		setStartDate(startdt.date());
	else
		setStartDateTime(startdt);
	return true;
}

/******************************************************************************
 * Initialise the recurrence from an iCalendar RRULE string.
 */
bool KARecurrence::set(const TQString& icalRRULE)
{
	static TQString RRULE = TQString::fromLatin1("RRULE:");
	mCachedType = -1;
	clear();
	if (icalRRULE.isEmpty())
		return true;
	ICalFormat format;
	if (!format.fromString(defaultRRule(true),
	                       (icalRRULE.startsWith(RRULE) ? icalRRULE.mid(RRULE.length()) : icalRRULE)))
		return false;
	fix();
	return true;
}

/******************************************************************************
* Must be called after presetting with a KCal::Recurrence, to convert the
* recurrence to KARecurrence types:
* - Convert hourly recurrences to minutely.
* - Remove all but the first day in yearly date recurrences.
* - Check for yearly recurrences falling on February 29th and adjust them as
*   necessary. A 29th of the month rule can be combined with either a 60th day
*   of the year rule or a last day of February rule.
*/
void KARecurrence::fix()
{
	mCachedType = -1;
	mFeb29Type = FEB29_FEB29;
	int convert = 0;
	int days[2] = { 0, 0 };
	RecurrenceRule* rrules[2];
	RecurrenceRule::List rrulelist = rRules();
	RecurrenceRule::List::ConstIterator rr = rrulelist.begin();
	for (int i = 0;  i < 2  &&  rr != rrulelist.end();  ++i, ++rr)
	{
		RecurrenceRule* rrule = *rr;
		rrules[i] = rrule;
		bool stop = true;
		int rtype = recurrenceType(rrule);
		switch (rtype)
		{
			case rHourly:
				// Convert an hourly recurrence to a minutely one
				rrule->setRecurrenceType(RecurrenceRule::rMinutely);
				rrule->setFrequency(rrule->frequency() * 60);
				// fall through to rMinutely
			case rMinutely:
			case rDaily:
			case rWeekly:
			case rMonthlyDay:
			case rMonthlyPos:
			case rYearlyPos:
				if (!convert)
					++rr;    // remove all rules except the first
				break;
			case rOther:
				if (dailyType(rrule))
				{                        // it's a daily rule with BYDAYS
					if (!convert)
						++rr;    // remove all rules except the first
				}
				break;
			case rYearlyDay:
			{
				// Ensure that the yearly day number is 60 (i.e. Feb 29th/Mar 1st)
				if (convert)
				{
					// This is the second rule.
					// Ensure that it can be combined with the first one.
					if (days[0] != 29
					||  rrule->frequency() != rrules[0]->frequency()
					||  rrule->startDt()   != rrules[0]->startDt())
						break;
				}
				TQValueList<int> ds = rrule->byYearDays();
				if (!ds.isEmpty()  &&  ds.first() == 60)
				{
					++convert;    // this rule needs to be converted
					days[i] = 60;
					stop = false;
					break;
				}
				break;     // not day 60, so remove this rule
			}
			case rYearlyMonth:
			{
				TQValueList<int> ds = rrule->byMonthDays();
				if (!ds.isEmpty())
				{
					int day = ds.first();
					if (convert)
					{
						// This is the second rule.
						// Ensure that it can be combined with the first one.
						if (day == days[0]  ||  (day == -1 && days[0] == 60)
						||  rrule->frequency() != rrules[0]->frequency()
						||  rrule->startDt()   != rrules[0]->startDt())
							break;
					}
					if (ds.count() > 1)
					{
						ds.clear();   // remove all but the first day
						ds.append(day);
						rrule->setByMonthDays(ds);
					}
					if (day == -1)
					{
						// Last day of the month - only combine if it's February
						TQValueList<int> months = rrule->byMonths();
						if (months.count() != 1  ||  months.first() != 2)
							day = 0;
					}
					if (day == 29  ||  day == -1)
					{
						++convert;    // this rule may need to be converted
						days[i] = day;
						stop = false;
						break;
					}
				}
				if (!convert)
					++rr;
				break;
			}
			default:
				break;
		}
		if (stop)
			break;
	}

	// Remove surplus rules
	for ( ;  rr != rrulelist.end();  ++rr)
	{
		removeRRule(*rr);
		delete *rr;
	}

	TQDate end;
	int count;
	TQValueList<int> months;
	if (convert == 2)
	{
		// There are two yearly recurrence rules to combine into a February 29th recurrence.
		// Combine the two recurrence rules into a single rYearlyMonth rule falling on Feb 29th.
		// Find the duration of the two RRULEs combined, using the shorter of the two if they differ.
		if (days[0] != 29)
		{
			// Swap the two rules so that the 29th rule is the first
			RecurrenceRule* rr = rrules[0];
			rrules[0] = rrules[1];    // the 29th rule
			rrules[1] = rr;
			int d = days[0];
			days[0] = days[1];
			days[1] = d;        // the non-29th day
		}
		// If February is included in the 29th rule, remove it to avoid duplication
		months = rrules[0]->byMonths();
		if (months.remove(2))
			rrules[0]->setByMonths(months);

		count = combineDurations(rrules[0], rrules[1], end);
		mFeb29Type = (days[1] == 60) ? FEB29_MAR1 : FEB29_FEB28;
	}
	else if (convert == 1  &&  days[0] == 60)
	{
		// There is a single 60th day of the year rule.
		// Convert it to a February 29th recurrence.
		count = duration();
		if (!count)
			end = endDate();
		mFeb29Type = FEB29_MAR1;
	}
	else
		return;

	// Create the new February 29th recurrence
	setNewRecurrenceType(RecurrenceRule::rYearly, frequency());
	RecurrenceRule* rrule = defaultRRule();
	months.append(2);
	rrule->setByMonths(months);
	TQValueList<int> ds;
	ds.append(29);
	rrule->setByMonthDays(ds);
	if (count)
		setDuration(count);
	else
		setEndDate(end);
}

/******************************************************************************
* Get the next time the recurrence occurs, strictly after a specified time.
*/
TQDateTime KARecurrence::getNextDateTime(const TQDateTime& preDateTime) const
{
	switch (type())
	{
		case ANNUAL_DATE:
		case ANNUAL_POS:
		{
			Recurrence recur;
			writeRecurrence(recur);
			return recur.getNextDateTime(preDateTime);
		}
		default:
			return Recurrence::getNextDateTime(preDateTime);
	}
}

/******************************************************************************
* Get the previous time the recurrence occurred, strictly before a specified time.
*/
TQDateTime KARecurrence::getPreviousDateTime(const TQDateTime& afterDateTime) const
{
	switch (type())
	{
		case ANNUAL_DATE:
		case ANNUAL_POS:
		{
			Recurrence recur;
			writeRecurrence(recur);
			return recur.getPreviousDateTime(afterDateTime);
		}
		default:
			return Recurrence::getPreviousDateTime(afterDateTime);
	}
}

/******************************************************************************
* Initialise a KCal::Recurrence to be the same as this instance.
* Additional recurrence rules are created as necessary if it recurs on Feb 29th.
*/
void KARecurrence::writeRecurrence(KCal::Recurrence& recur) const
{
	recur.clear();
	recur.setStartDateTime(startDateTime());
	recur.setExDates(exDates());
	recur.setExDateTimes(exDateTimes());
	const RecurrenceRule* rrule = defaultRRuleConst();
	if (!rrule)
		return;
	int freq  = frequency();
	int count = duration();
	static_cast<KARecurrence*>(&recur)->setNewRecurrenceType(rrule->recurrenceType(), freq);
	if (count)
		recur.setDuration(count);
	else
		recur.setEndDateTime(endDateTime());
	switch (type())
	{
		case DAILY:
			if (rrule->byDays().isEmpty())
				break;
			// fall through to rWeekly
		case WEEKLY:
		case MONTHLY_POS:
			recur.defaultRRule(true)->setByDays(rrule->byDays());
			break;
		case MONTHLY_DAY:
			recur.defaultRRule(true)->setByMonthDays(rrule->byMonthDays());
			break;
		case ANNUAL_POS:
			recur.defaultRRule(true)->setByMonths(rrule->byMonths());
			recur.defaultRRule()->setByDays(rrule->byDays());
			break;
		case ANNUAL_DATE:
		{
			TQValueList<int> months = rrule->byMonths();
			TQValueList<int> days   = monthDays();
			bool special = (mFeb29Type != FEB29_FEB29  &&  !days.isEmpty()
			                &&  days.first() == 29  &&  months.remove(2));
			RecurrenceRule* rrule1 = recur.defaultRRule();
			rrule1->setByMonths(months);
			rrule1->setByMonthDays(days);
			if (!special)
				break;

			// It recurs on the 29th February.
			// Create an additional 60th day of the year, or last day of February, rule.
			RecurrenceRule* rrule2 = new RecurrenceRule();
			rrule2->setRecurrenceType(RecurrenceRule::rYearly);
			rrule2->setFrequency(freq);
			rrule2->setStartDt(startDateTime());
			rrule2->setFloats(doesFloat());
			if (!count)
				rrule2->setEndDt(endDateTime());
			if (mFeb29Type == FEB29_MAR1)
			{
				TQValueList<int> ds;
				ds.append(60);
				rrule2->setByYearDays(ds);
			}
			else
			{
				TQValueList<int> ds;
				ds.append(-1);
				rrule2->setByMonthDays(ds);
				TQValueList<int> ms;
				ms.append(2);
				rrule2->setByMonths(ms);
			}

			if (months.isEmpty())
			{
				// Only February recurs.
				// Replace the RRULE and keep the recurrence count the same.
				if (count)
					rrule2->setDuration(count);
				recur.unsetRecurs();
			}
			else
			{
				// Months other than February also recur on the 29th.
				// Remove February from the list and add a separate RRULE for February.
				if (count)
				{
					rrule1->setDuration(-1);
					rrule2->setDuration(-1);
					if (count > 0)
					{
						/* Adjust counts in the two rules to keep the correct occurrence total.
						 * Note that durationTo() always includes the start date. Since for an
						 * individual RRULE the start date may not actually be included, we need
						 * to decrement the count if the start date doesn't actually recur in
						 * this RRULE.
						 * Note that if the count is small, one of the rules may not recur at
						 * all. In that case, retain it so that the February 29th characteristic
						 * is not lost should the user later change the recurrence count.
						 */
						TQDateTime end = endDateTime();
kdDebug()<<"29th recurrence: count="<<count<<", end date="<<end.toString()<<endl;
						int count1 = rrule1->durationTo(end)
						             - (rrule1->recursOn(startDate()) ? 0 : 1);
						if (count1 > 0)
							rrule1->setDuration(count1);
						else
							rrule1->setEndDt(startDateTime());
						int count2 = rrule2->durationTo(end)
						             - (rrule2->recursOn(startDate()) ? 0 : 1);
						if (count2 > 0)
							rrule2->setDuration(count2);
						else
							rrule2->setEndDt(startDateTime());
					}
				}
			}
			recur.addRRule(rrule2);
			break;
		}
		default:
			break;
	}
}

/******************************************************************************
* Return the date/time of the last recurrence.
*/
TQDateTime KARecurrence::endDateTime() const
{
	if (mFeb29Type == FEB29_FEB29  ||  duration() <= 1)
	{
		/* Either it doesn't have any special February 29th treatment,
		 * it's infinite (count = -1), the end date is specified
		 * (count = 0), or it ends on the start date (count = 1).
		 * So just use the normal KCal end date calculation.
		 */
		return Recurrence::endDateTime();
	}

	/* Create a temporary recurrence rule to find the end date.
	 * In a standard KCal recurrence, the 29th February only occurs once every
	 * 4 years. So shift the temporary recurrence date to the 28th to ensure
	 * that it occurs every year, thus giving the correct occurrence count.
	 */
	RecurrenceRule* rrule = new RecurrenceRule();
	rrule->setRecurrenceType(RecurrenceRule::rYearly);
	TQDateTime dt = startDateTime();
	TQDate d = dt.date();
	switch (d.day())
	{
		case 29:
			// The start date is definitely a recurrence date, so shift
			// start date to the temporary recurrence date of the 28th
			d.setYMD(d.year(), d.month(), 28);
			break;
		case 28:
			if (d.month() != 2  ||  mFeb29Type != FEB29_FEB28  ||  TQDate::leapYear(d.year()))
			{
				// Start date is not a recurrence date, so shift it to 27th
				d.setYMD(d.year(), d.month(), 27);
			}
			break;
		case 1:
			if (d.month() == 3  &&  mFeb29Type == FEB29_MAR1  &&  !TQDate::leapYear(d.year()))
			{
				// Start date is a March 1st recurrence date, so shift
				// start date to the temporary recurrence date of the 28th
				d.setYMD(d.year(), 2, 28);
			}
			break;
		default:
			break;
	}
	dt.setDate(d);
	rrule->setStartDt(dt);
	rrule->setFloats(doesFloat());
	rrule->setFrequency(frequency());
	rrule->setDuration(duration());
	TQValueList<int> ds;
	ds.append(28);
	rrule->setByMonthDays(ds);
	rrule->setByMonths(defaultRRuleConst()->byMonths());
	dt = rrule->endDt();
	delete rrule;

	// We've found the end date for a recurrence on the 28th. Unless that date
	// is a real February 28th recurrence, adjust to the actual recurrence date.
	if (mFeb29Type == FEB29_FEB28  &&  dt.date().month() == 2  &&  !TQDate::leapYear(dt.date().year()))
		return dt;
	return dt.addDays(1);
}

/******************************************************************************
* Return the date/time of the last recurrence.
*/
TQDate KARecurrence::endDate() const
{
	TQDateTime end = endDateTime();
	return end.isValid() ? end.date() : TQDate();
}

/******************************************************************************
* Return whether the event will recur on the specified date.
* The start date only returns true if it matches the recurrence rules.
*/
bool KARecurrence::recursOn(const TQDate& dt) const
{
	if (!Recurrence::recursOn(dt))
		return false;
	if (dt != startDate())
		return true;
	// We know now that it isn't in EXDATES or EXRULES,
	// so we just need to check if it's in RDATES or RRULES
	if (rDates().contains(dt))
		return true;
	RecurrenceRule::List rulelist = rRules();
	for (RecurrenceRule::List::ConstIterator rr = rulelist.begin();  rr != rulelist.end();  ++rr)
		if ((*rr)->recursOn(dt))
			return true;
	DateTimeList dtlist = rDateTimes();
	for (DateTimeList::ConstIterator rdt = dtlist.begin();  rdt != dtlist.end();  ++rdt)
		if ((*rdt).date() == dt)
			return true;
	return false;
}

/******************************************************************************
* Find the duration of two RRULEs combined.
* Use the shorter of the two if they differ.
*/
int KARecurrence::combineDurations(const RecurrenceRule* rrule1, const RecurrenceRule* rrule2, TQDate& end) const
{
	int count1 = rrule1->duration();
	int count2 = rrule2->duration();
	if (count1 == -1  &&  count2 == -1)
		return -1;

	// One of the RRULEs may not recur at all if the recurrence count is small.
	// In this case, its end date will have been set to the start date.
	if (count1  &&  !count2  &&  rrule2->endDt().date() == startDateTime().date())
		return count1;
	if (count2  &&  !count1  &&  rrule1->endDt().date() == startDateTime().date())
		return count2;

	/* The duration counts will be different even for RRULEs of the same length,
	 * because the first RRULE only actually occurs every 4 years. So we need to
	 * compare the end dates.
	 */
	if (!count1  ||  !count2)
		count1 = count2 = 0;
	// Get the two rules sorted by end date.
	TQDateTime end1 = rrule1->endDt();
	TQDateTime end2 = rrule2->endDt();
	if (end1.date() == end2.date())
	{
		end = end1.date();
		return count1 + count2;
	}
	const RecurrenceRule* rr1;    // earlier end date
	const RecurrenceRule* rr2;    // later end date
	if (end2.isValid()
	&&  (!end1.isValid()  ||  end1.date() > end2.date()))
	{
		// Swap the two rules to make rr1 have the earlier end date
		rr1 = rrule2;
		rr2 = rrule1;
		TQDateTime e = end1;
		end1 = end2;
		end2 = e;
	}
	else
	{
		rr1 = rrule1;
		rr2 = rrule2;
	}

	// Get the date of the next occurrence after the end of the earlier ending rule
	RecurrenceRule rr(*rr1);
	rr.setDuration(-1);
	TQDateTime next1(rr.getNextDate(end1).date());
	if (!next1.isValid())
		end = end1.date();
	else
	{
		if (end2.isValid()  &&  next1 > end2)
		{
			// The next occurrence after the end of the earlier ending rule
			// is later than the end of the later ending rule. So simply use
			// the end date of the later rule.
			end = end2.date();
			return count1 + count2;
		}
		TQDate prev2 = rr2->getPreviousDate(next1).date();
		end = (prev2 > end1.date()) ? prev2 : end1.date();
	}
	if (count2)
		count2 = rr2->durationTo(end);
	return count1 + count2;
}

/******************************************************************************
 * Return the longest interval (in minutes) between recurrences.
 * Reply = 0 if it never recurs.
 */
int KARecurrence::longestInterval() const
{
	int freq = frequency();
	switch (type())
	{
		case MINUTELY:
			return freq;

		case DAILY:
		{
			TQValueList<RecurrenceRule::WDayPos> days = defaultRRuleConst()->byDays();
			if (days.isEmpty())
				return freq * 1440;

			// It recurs only on certain days of the week, so the maximum interval
			// may be greater than the frequency.
			bool ds[7] = { false, false, false, false, false, false, false };
			for (TQValueList<RecurrenceRule::WDayPos>::ConstIterator it = days.begin();  it != days.end();  ++it)
				if ((*it).pos() == 0)
					ds[(*it).day() - 1] = true;
			if (freq % 7)
			{
				// It will recur on every day of the week in some week or other
				// (except for those days which are excluded).
				int first = -1;
				int last  = -1;
				int maxgap = 1;
				for (int i = 0;  i < freq*7;  i += freq)
				{
					if (ds[i % 7])
					{
						if (first < 0)
							first = i;
						else if (i - last > maxgap)
							maxgap = i - last;
						last = i;
					}
				}
				int wrap = freq*7 - last + first;
				if (wrap > maxgap)
					maxgap = wrap;
				return maxgap * 1440;
			}
			else
			{
				// It will recur on the same day of the week every time.
				// Ensure that the day is a day which is not excluded.
				return ds[startDate().dayOfWeek() - 1] ? freq * 1440 : 0;
			}
		}
		case WEEKLY:
		{
			// Find which days of the week it recurs on, and if on more than
			// one, reduce the maximum interval accordingly.
			TQBitArray ds = days();
			int first = -1;
			int last  = -1;
			int maxgap = 1;
			for (int i = 0;  i < 7;  ++i)
			{
				if (ds.testBit(KAlarm::localeDayInWeek_to_weekDay(i) - 1))
				{
					if (first < 0)
						first = i;
					else if (i - last > maxgap)
						maxgap = i - last;
					last = i;
				}
			}
			if (first < 0)
				break;    // no days recur
			int span = last - first;
			if (freq > 1)
				return (freq*7 - span) * 1440;
			if (7 - span > maxgap)
				return (7 - span) * 1440;
			return maxgap * 1440;
		}
		case MONTHLY_DAY:
		case MONTHLY_POS:
			return freq * 1440 * 31;

		case ANNUAL_DATE:
		case ANNUAL_POS:
		{
			// Find which months of the year it recurs on, and if on more than
			// one, reduce the maximum interval accordingly.
			const TQValueList<int> months = yearMonths();  // month list is sorted
			if (months.isEmpty())
				break;    // no months recur
			if (months.count() == 1)
				return freq * 1440 * 365;
			int first = -1;
			int last  = -1;
			int maxgap = 0;
			for (TQValueListConstIterator<int> it = months.begin();  it != months.end();  ++it)
			{
				if (first < 0)
					first = *it;
				else
				{
					int span = TQDate(2001, last, 1).daysTo(TQDate(2001, *it, 1));
					if (span > maxgap)
						maxgap = span;
				}
				last = *it;
			}
			int span = TQDate(2001, first, 1).daysTo(TQDate(2001, last, 1));
			if (freq > 1)
				return (freq*365 - span) * 1440;
			if (365 - span > maxgap)
				return (365 - span) * 1440;
			return maxgap * 1440;
		}
		default:
			break;
	}
	return 0;
}

/******************************************************************************
 * Return the recurrence's period type.
 */
KARecurrence::Type KARecurrence::type() const
{
	if (mCachedType == -1)
		mCachedType = type(defaultRRuleConst());
	return static_cast<Type>(mCachedType);
}

KARecurrence::Type KARecurrence::type(const RecurrenceRule* rrule)
{
	switch (recurrenceType(rrule))
	{
		case rMinutely:     return MINUTELY;
		case rDaily:        return DAILY;
		case rWeekly:       return WEEKLY;
		case rMonthlyDay:   return MONTHLY_DAY;
		case rMonthlyPos:   return MONTHLY_POS;
		case rYearlyMonth:  return ANNUAL_DATE;
		case rYearlyPos:    return ANNUAL_POS;
		default:
			if (dailyType(rrule))
				return DAILY;
			return NO_RECUR;
	}
}

/******************************************************************************
 * Check if the rule is a daily rule with or without BYDAYS specified.
 */
bool KARecurrence::dailyType(const RecurrenceRule* rrule)
{
	if (rrule->recurrenceType() != RecurrenceRule::rDaily
	||  !rrule->bySeconds().isEmpty()
	||  !rrule->byMinutes().isEmpty()
	||  !rrule->byHours().isEmpty()
	||  !rrule->byWeekNumbers().isEmpty()
	||  !rrule->byMonthDays().isEmpty()
	||  !rrule->byMonths().isEmpty()
	||  !rrule->bySetPos().isEmpty()
	||  !rrule->byYearDays().isEmpty())
		return false;
	TQValueList<RecurrenceRule::WDayPos> days = rrule->byDays();
	if (days.isEmpty())
		return true;
	// Check that all the positions are zero (i.e. every time)
	bool found = false;
	for (TQValueList<RecurrenceRule::WDayPos>::ConstIterator it = days.begin();  it != days.end();  ++it)
	{
		if ((*it).pos() != 0)
			return false;
		found = true;
	}
	return found;

}