summaryrefslogtreecommitdiff
path: root/src/mscorlib/shared/System/Globalization/HijriCalendar.cs
blob: cafde5fbb8538746a24416acda6834f4d202b4c7 (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
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Diagnostics.Contracts;

namespace System.Globalization
{
    ////////////////////////////////////////////////////////////////////////////
    //
    //  Rules for the Hijri calendar:
    //    - The Hijri calendar is a strictly Lunar calendar.
    //    - Days begin at sunset.
    //    - Islamic Year 1 (Muharram 1, 1 A.H.) is equivalent to absolute date
    //        227015 (Friday, July 16, 622 C.E. - Julian).
    //    - Leap Years occur in the 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, & 29th
    //        years of a 30-year cycle.  Year = leap iff ((11y+14) mod 30 < 11).
    //    - There are 12 months which contain alternately 30 and 29 days.
    //    - The 12th month, Dhu al-Hijjah, contains 30 days instead of 29 days
    //        in a leap year.
    //    - Common years have 354 days.  Leap years have 355 days.
    //    - There are 10,631 days in a 30-year cycle.
    //    - The Islamic months are:
    //        1.  Muharram   (30 days)     7.  Rajab          (30 days)
    //        2.  Safar      (29 days)     8.  Sha'ban        (29 days)
    //        3.  Rabi I     (30 days)     9.  Ramadan        (30 days)
    //        4.  Rabi II    (29 days)     10. Shawwal        (29 days)
    //        5.  Jumada I   (30 days)     11. Dhu al-Qada    (30 days)
    //        6.  Jumada II  (29 days)     12. Dhu al-Hijjah  (29 days) {30}
    //
    //  NOTENOTE
    //      The calculation of the HijriCalendar is based on the absolute date.  And the
    //      absolute date means the number of days from January 1st, 1 A.D.
    //      Therefore, we do not support the days before the January 1st, 1 A.D.
    //
    ////////////////////////////////////////////////////////////////////////////
    /*
    **  Calendar support range:
    **      Calendar    Minimum     Maximum
    **      ==========  ==========  ==========
    **      Gregorian   0622/07/18   9999/12/31
    **      Hijri       0001/01/01   9666/04/03
    */

    [Serializable]
    public partial class HijriCalendar : Calendar
    {
        public static readonly int HijriEra = 1;

        internal const int DatePartYear = 0;
        internal const int DatePartDayOfYear = 1;
        internal const int DatePartMonth = 2;
        internal const int DatePartDay = 3;

        internal const int MinAdvancedHijri = -2;
        internal const int MaxAdvancedHijri = 2;

        internal static readonly int[] HijriMonthDays = { 0, 30, 59, 89, 118, 148, 177, 207, 236, 266, 295, 325, 355 };

        private int _hijriAdvance = Int32.MinValue;

        // DateTime.MaxValue = Hijri calendar (year:9666, month: 4, day: 3).
        internal const int MaxCalendarYear = 9666;
        internal const int MaxCalendarMonth = 4;
        internal const int MaxCalendarDay = 3;
        // Hijri calendar (year: 1, month: 1, day:1 ) = Gregorian (year: 622, month: 7, day: 18)
        // This is the minimal Gregorian date that we support in the HijriCalendar.
        internal static readonly DateTime calendarMinValue = new DateTime(622, 7, 18);
        internal static readonly DateTime calendarMaxValue = DateTime.MaxValue;


        public override DateTime MinSupportedDateTime
        {
            get
            {
                return (calendarMinValue);
            }
        }


        public override DateTime MaxSupportedDateTime
        {
            get
            {
                return (calendarMaxValue);
            }
        }

        public override CalendarAlgorithmType AlgorithmType
        {
            get
            {
                return CalendarAlgorithmType.LunarCalendar;
            }
        }

        public HijriCalendar()
        {
        }

        internal override CalendarId ID
        {
            get
            {
                return CalendarId.HIJRI;
            }
        }

        protected override int DaysInYearBeforeMinSupportedYear
        {
            get
            {
                // the year before the 1st year of the cycle would have been the 30th year
                // of the previous cycle which is not a leap year. Common years have 354 days.
                return 354;
            }
        }



        /*=================================GetAbsoluteDateHijri==========================
        **Action: Gets the Absolute date for the given Hijri date.  The absolute date means
        **       the number of days from January 1st, 1 A.D.
        **Returns:
        **Arguments:
        **Exceptions:
        ============================================================================*/

        private long GetAbsoluteDateHijri(int y, int m, int d)
        {
            return (long)(DaysUpToHijriYear(y) + HijriMonthDays[m - 1] + d - 1 - HijriAdjustment);
        }

        /*=================================DaysUpToHijriYear==========================
        **Action: Gets the total number of days (absolute date) up to the given Hijri Year.
        **       The absolute date means the number of days from January 1st, 1 A.D.
        **Returns: Gets the total number of days (absolute date) up to the given Hijri Year.
        **Arguments: HijriYear year value in Hijri calendar.
        **Exceptions: None
        **Notes:
        ============================================================================*/

        private long DaysUpToHijriYear(int HijriYear)
        {
            long NumDays;           // number of absolute days
            int NumYear30;         // number of years up to current 30 year cycle
            int NumYearsLeft;      // number of years into 30 year cycle

            //
            //  Compute the number of years up to the current 30 year cycle.
            //
            NumYear30 = ((HijriYear - 1) / 30) * 30;

            //
            //  Compute the number of years left.  This is the number of years
            //  into the 30 year cycle for the given year.
            //
            NumYearsLeft = HijriYear - NumYear30 - 1;

            //
            //  Compute the number of absolute days up to the given year.
            //
            NumDays = ((NumYear30 * 10631L) / 30L) + 227013L;
            while (NumYearsLeft > 0)
            {
                // Common year is 354 days, and leap year is 355 days.
                NumDays += 354 + (IsLeapYear(NumYearsLeft, CurrentEra) ? 1 : 0);
                NumYearsLeft--;
            }

            //
            //  Return the number of absolute days.
            //
            return (NumDays);
        }

        public int HijriAdjustment
        {
            get
            {
                if (_hijriAdvance == Int32.MinValue)
                {
                    // Never been set before.  Use the system value from registry.
                    _hijriAdvance = GetHijriDateAdjustment();
                }
                return (_hijriAdvance);
            }

            set
            {
                // NOTE: Check the value of Min/MaxAdavncedHijri with Arabic speakers to see if the assumption is good.
                if (value < MinAdvancedHijri || value > MaxAdvancedHijri)
                {
                    throw new ArgumentOutOfRangeException(
                                "HijriAdjustment",
                                String.Format(
                                    CultureInfo.CurrentCulture,
                                    SR.ArgumentOutOfRange_Bounds_Lower_Upper,
                                    MinAdvancedHijri,
                                    MaxAdvancedHijri));
                }
                Contract.EndContractBlock();
                VerifyWritable();

                _hijriAdvance = value;
            }
        }

        internal static void CheckTicksRange(long ticks)
        {
            if (ticks < calendarMinValue.Ticks || ticks > calendarMaxValue.Ticks)
            {
                throw new ArgumentOutOfRangeException(
                            "time",
                            String.Format(
                                CultureInfo.InvariantCulture,
                                SR.ArgumentOutOfRange_CalendarRange,
                                calendarMinValue,
                                calendarMaxValue));
            }
        }

        internal static void CheckEraRange(int era)
        {
            if (era != CurrentEra && era != HijriEra)
            {
                throw new ArgumentOutOfRangeException(nameof(era), SR.ArgumentOutOfRange_InvalidEraValue);
            }
        }

        internal static void CheckYearRange(int year, int era)
        {
            CheckEraRange(era);
            if (year < 1 || year > MaxCalendarYear)
            {
                throw new ArgumentOutOfRangeException(
                            nameof(year),
                            String.Format(
                                CultureInfo.CurrentCulture,
                                SR.ArgumentOutOfRange_Range,
                                1,
                                MaxCalendarYear));
            }
        }

        internal static void CheckYearMonthRange(int year, int month, int era)
        {
            CheckYearRange(year, era);
            if (year == MaxCalendarYear)
            {
                if (month > MaxCalendarMonth)
                {
                    throw new ArgumentOutOfRangeException(
                                nameof(month),
                                String.Format(
                                    CultureInfo.CurrentCulture,
                                    SR.ArgumentOutOfRange_Range,
                                    1,
                                    MaxCalendarMonth));
                }
            }

            if (month < 1 || month > 12)
            {
                throw new ArgumentOutOfRangeException(nameof(month), SR.ArgumentOutOfRange_Month);
            }
        }

        /*=================================GetDatePart==========================
        **Action: Returns a given date part of this <i>DateTime</i>. This method is used
        **       to compute the year, day-of-year, month, or day part.
        **Returns:
        **Arguments:
        **Exceptions:  ArgumentException if part is incorrect.
        **Notes:
        **      First, we get the absolute date (the number of days from January 1st, 1 A.C) for the given ticks.
        **      Use the formula (((AbsoluteDate - 227013) * 30) / 10631) + 1, we can a rough value for the Hijri year.
        **      In order to get the exact Hijri year, we compare the exact absolute date for HijriYear and (HijriYear + 1).
        **      From here, we can get the correct Hijri year.
        ============================================================================*/

        internal virtual int GetDatePart(long ticks, int part)
        {
            int HijriYear;                   // Hijri year
            int HijriMonth;                  // Hijri month
            int HijriDay;                    // Hijri day
            long NumDays;                 // The calculation buffer in number of days.

            CheckTicksRange(ticks);

            //
            //  Get the absolute date.  The absolute date is the number of days from January 1st, 1 A.D.
            //  1/1/0001 is absolute date 1.
            //
            NumDays = ticks / GregorianCalendar.TicksPerDay + 1;

            //
            //  See how much we need to backup or advance
            //
            NumDays += HijriAdjustment;

            //
            //  Calculate the appromixate Hijri Year from this magic formula.
            //
            HijriYear = (int)(((NumDays - 227013) * 30) / 10631) + 1;

            long daysToHijriYear = DaysUpToHijriYear(HijriYear);            // The absoulte date for HijriYear
            long daysOfHijriYear = GetDaysInYear(HijriYear, CurrentEra);    // The number of days for (HijriYear+1) year.

            if (NumDays < daysToHijriYear)
            {
                daysToHijriYear -= daysOfHijriYear;
                HijriYear--;
            }
            else if (NumDays == daysToHijriYear)
            {
                HijriYear--;
                daysToHijriYear -= GetDaysInYear(HijriYear, CurrentEra);
            }
            else
            {
                if (NumDays > daysToHijriYear + daysOfHijriYear)
                {
                    daysToHijriYear += daysOfHijriYear;
                    HijriYear++;
                }
            }
            if (part == DatePartYear)
            {
                return (HijriYear);
            }

            //
            //  Calculate the Hijri Month.
            //

            HijriMonth = 1;
            NumDays -= daysToHijriYear;

            if (part == DatePartDayOfYear)
            {
                return ((int)NumDays);
            }

            while ((HijriMonth <= 12) && (NumDays > HijriMonthDays[HijriMonth - 1]))
            {
                HijriMonth++;
            }
            HijriMonth--;

            if (part == DatePartMonth)
            {
                return (HijriMonth);
            }

            //
            //  Calculate the Hijri Day.
            //
            HijriDay = (int)(NumDays - HijriMonthDays[HijriMonth - 1]);

            if (part == DatePartDay)
            {
                return (HijriDay);
            }
            // Incorrect part value.
            throw new InvalidOperationException(SR.InvalidOperation_DateTimeParsing);
        }

        // Returns the DateTime resulting from adding the given number of
        // months to the specified DateTime. The result is computed by incrementing
        // (or decrementing) the year and month parts of the specified DateTime by
        // value months, and, if required, adjusting the day part of the
        // resulting date downwards to the last day of the resulting month in the
        // resulting year. The time-of-day part of the result is the same as the
        // time-of-day part of the specified DateTime.
        //
        // In more precise terms, considering the specified DateTime to be of the
        // form y / m / d + t, where y is the
        // year, m is the month, d is the day, and t is the
        // time-of-day, the result is y1 / m1 / d1 + t,
        // where y1 and m1 are computed by adding value months
        // to y and m, and d1 is the largest value less than
        // or equal to d that denotes a valid day in month m1 of year
        // y1.
        //

        public override DateTime AddMonths(DateTime time, int months)
        {
            if (months < -120000 || months > 120000)
            {
                throw new ArgumentOutOfRangeException(
                            nameof(months),
                            String.Format(
                                CultureInfo.CurrentCulture,
                                SR.ArgumentOutOfRange_Range,
                                -120000,
                                120000));
            }
            Contract.EndContractBlock();
            // Get the date in Hijri calendar.
            int y = GetDatePart(time.Ticks, DatePartYear);
            int m = GetDatePart(time.Ticks, DatePartMonth);
            int d = GetDatePart(time.Ticks, DatePartDay);
            int i = m - 1 + months;
            if (i >= 0)
            {
                m = i % 12 + 1;
                y = y + i / 12;
            }
            else
            {
                m = 12 + (i + 1) % 12;
                y = y + (i - 11) / 12;
            }
            int days = GetDaysInMonth(y, m);
            if (d > days)
            {
                d = days;
            }
            long ticks = GetAbsoluteDateHijri(y, m, d) * TicksPerDay + (time.Ticks % TicksPerDay);
            Calendar.CheckAddResult(ticks, MinSupportedDateTime, MaxSupportedDateTime);
            return (new DateTime(ticks));
        }

        // Returns the DateTime resulting from adding the given number of
        // years to the specified DateTime. The result is computed by incrementing
        // (or decrementing) the year part of the specified DateTime by value
        // years. If the month and day of the specified DateTime is 2/29, and if the
        // resulting year is not a leap year, the month and day of the resulting
        // DateTime becomes 2/28. Otherwise, the month, day, and time-of-day
        // parts of the result are the same as those of the specified DateTime.
        //

        public override DateTime AddYears(DateTime time, int years)
        {
            return (AddMonths(time, years * 12));
        }

        // Returns the day-of-month part of the specified DateTime. The returned
        // value is an integer between 1 and 31.
        //

        public override int GetDayOfMonth(DateTime time)
        {
            return (GetDatePart(time.Ticks, DatePartDay));
        }

        // Returns the day-of-week part of the specified DateTime. The returned value
        // is an integer between 0 and 6, where 0 indicates Sunday, 1 indicates
        // Monday, 2 indicates Tuesday, 3 indicates Wednesday, 4 indicates
        // Thursday, 5 indicates Friday, and 6 indicates Saturday.
        //

        public override DayOfWeek GetDayOfWeek(DateTime time)
        {
            return ((DayOfWeek)((int)(time.Ticks / TicksPerDay + 1) % 7));
        }

        // Returns the day-of-year part of the specified DateTime. The returned value
        // is an integer between 1 and 366.
        //

        public override int GetDayOfYear(DateTime time)
        {
            return (GetDatePart(time.Ticks, DatePartDayOfYear));
        }

        // Returns the number of days in the month given by the year and
        // month arguments.
        //
        [Pure]
        public override int GetDaysInMonth(int year, int month, int era)
        {
            CheckYearMonthRange(year, month, era);
            if (month == 12)
            {
                // For the 12th month, leap year has 30 days, and common year has 29 days.
                return (IsLeapYear(year, CurrentEra) ? 30 : 29);
            }
            // Other months contain 30 and 29 days alternatively.  The 1st month has 30 days.
            return (((month % 2) == 1) ? 30 : 29);
        }

        // Returns the number of days in the year given by the year argument for the current era.
        //

        public override int GetDaysInYear(int year, int era)
        {
            CheckYearRange(year, era);
            // Common years have 354 days.  Leap years have 355 days.
            return (IsLeapYear(year, CurrentEra) ? 355 : 354);
        }

        // Returns the era for the specified DateTime value.

        public override int GetEra(DateTime time)
        {
            CheckTicksRange(time.Ticks);
            return (HijriEra);
        }


        public override int[] Eras
        {
            get
            {
                return (new int[] { HijriEra });
            }
        }

        // Returns the month part of the specified DateTime. The returned value is an
        // integer between 1 and 12.
        //

        public override int GetMonth(DateTime time)
        {
            return (GetDatePart(time.Ticks, DatePartMonth));
        }

        // Returns the number of months in the specified year and era.

        public override int GetMonthsInYear(int year, int era)
        {
            CheckYearRange(year, era);
            return (12);
        }

        // Returns the year part of the specified DateTime. The returned value is an
        // integer between 1 and MaxCalendarYear.
        //

        public override int GetYear(DateTime time)
        {
            return (GetDatePart(time.Ticks, DatePartYear));
        }

        // Checks whether a given day in the specified era is a leap day. This method returns true if
        // the date is a leap day, or false if not.
        //

        public override bool IsLeapDay(int year, int month, int day, int era)
        {
            // The year/month/era value checking is done in GetDaysInMonth().
            int daysInMonth = GetDaysInMonth(year, month, era);
            if (day < 1 || day > daysInMonth)
            {
                throw new ArgumentOutOfRangeException(
                            nameof(day),
                            String.Format(
                                CultureInfo.CurrentCulture,
                                SR.ArgumentOutOfRange_Day,
                                daysInMonth,
                                month));
            }
            return (IsLeapYear(year, era) && month == 12 && day == 30);
        }

        // Returns  the leap month in a calendar year of the specified era. This method returns 0
        // if this calendar does not have leap month, or this year is not a leap year.
        //

        public override int GetLeapMonth(int year, int era)
        {
            CheckYearRange(year, era);
            return (0);
        }

        // Checks whether a given month in the specified era is a leap month. This method returns true if
        // month is a leap month, or false if not.
        //

        public override bool IsLeapMonth(int year, int month, int era)
        {
            CheckYearMonthRange(year, month, era);
            return (false);
        }

        // Checks whether a given year in the specified era is a leap year. This method returns true if
        // year is a leap year, or false if not.
        //

        public override bool IsLeapYear(int year, int era)
        {
            CheckYearRange(year, era);
            return ((((year * 11) + 14) % 30) < 11);
        }

        // Returns the date and time converted to a DateTime value.  Throws an exception if the n-tuple is invalid.
        //

        public override DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era)
        {
            // The year/month/era checking is done in GetDaysInMonth().
            int daysInMonth = GetDaysInMonth(year, month, era);
            if (day < 1 || day > daysInMonth)
            {
                throw new ArgumentOutOfRangeException(
                            nameof(day),
                            String.Format(
                                CultureInfo.CurrentCulture,
                                SR.ArgumentOutOfRange_Day,
                                daysInMonth,
                                month));
            }

            long lDate = GetAbsoluteDateHijri(year, month, day);

            if (lDate >= 0)
            {
                return (new DateTime(lDate * GregorianCalendar.TicksPerDay + TimeToTicks(hour, minute, second, millisecond)));
            }
            else
            {
                throw new ArgumentOutOfRangeException(null, SR.ArgumentOutOfRange_BadYearMonthDay);
            }
        }

        private const int DEFAULT_TWO_DIGIT_YEAR_MAX = 1451;


        public override int TwoDigitYearMax
        {
            get
            {
                if (twoDigitYearMax == -1)
                {
                    twoDigitYearMax = GetSystemTwoDigitYearSetting(ID, DEFAULT_TWO_DIGIT_YEAR_MAX);
                }
                return (twoDigitYearMax);
            }

            set
            {
                VerifyWritable();
                if (value < 99 || value > MaxCalendarYear)
                {
                    throw new ArgumentOutOfRangeException(
                                nameof(value),
                                String.Format(
                                    CultureInfo.CurrentCulture,
                                    SR.ArgumentOutOfRange_Range,
                                    99,
                                    MaxCalendarYear));
                }
                twoDigitYearMax = value;
            }
        }


        public override int ToFourDigitYear(int year)
        {
            if (year < 0)
            {
                throw new ArgumentOutOfRangeException(nameof(year),
                    SR.ArgumentOutOfRange_NeedNonNegNum);
            }
            Contract.EndContractBlock();

            if (year < 100)
            {
                return (base.ToFourDigitYear(year));
            }

            if (year > MaxCalendarYear)
            {
                throw new ArgumentOutOfRangeException(
                            nameof(year),
                            String.Format(
                                CultureInfo.CurrentCulture,
                                SR.ArgumentOutOfRange_Range,
                                1,
                                MaxCalendarYear));
            }
            return (year);
        }
    }
}