// 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 DateTime. 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); } } }