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The Labs \ Source Viewer \ SSCLI \ System.Globalization \ GregorianCalendar

SSCLI

// ==++==
//
//
//
// The use and distribution terms for this software are contained in the file
// named license.txt, which can be found in the root of this distribution.
// By using this software in any fashion, you are agreeing to be bound by the
// terms of this license.
//
// You must not remove this notice, or any other, from this software.
//
//
// ==--==
namespace System.Globalization
{
//
// N.B.:
// A lot of this code is directly from DateTime.cs. If you update that class,
// update this one as well.
// However, we still need these duplicated code because we will add era support
// in this class.
//
//
using System.Threading;
using System;
using System.Globalization;
//
// This class implements the Gregorian calendar. In 1582, Pope Gregory XIII made
// minor changes to the solar Julian or "Old Style" calendar to make it more
// accurate. Thus the calendar became known as the Gregorian or "New Style"
// calendar, and adopted in Catholic countries such as Spain and France. Later
// the Gregorian calendar became popular throughout Western Europe because it
// was accurate and convenient for international trade. Scandinavian countries
// adopted it in 1700, Great Britain in 1752, the American colonies in 1752 and
// India in 1757. China adopted the same calendar in 1911, Russia in 1918, and
// some Eastern European countries as late as 1940.
//
// This calendar recognizes two era values:
// 0 CurrentEra (AD)
// 1 BeforeCurrentEra (BC)
[System.Runtime.InteropServices.ComVisible(true)]
[Serializable()]
public class GregorianCalendar : Calendar
{
/*
A.D. = anno Domini (after the birth of Jesus Christ)
*/
public const int ADEra = 1;
internal const int DatePartYear = 0;
internal const int DatePartDayOfYear = 1;
internal const int DatePartMonth = 2;
internal const int DatePartDay = 3;
//
// This is the max Gregorian year can be represented by DateTime class. The limitation
// is derived from DateTime class.
//
internal const int MaxYear = 9999;
internal GregorianCalendarTypes m_type;
static internal readonly int[] DaysToMonth365 = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273,
304, 334, 365};
static internal readonly int[] DaysToMonth366 = {0, 31, 60, 91, 121, 152, 182, 213, 244, 274,
305, 335, 366};
static internal Calendar m_defaultInstance = null;
[System.Runtime.InteropServices.ComVisible(false)]
public override DateTime MinSupportedDateTime {
get { return (DateTime.MinValue); }
}
[System.Runtime.InteropServices.ComVisible(false)]
public override DateTime MaxSupportedDateTime {
get { return (DateTime.MaxValue); }
}
// Return the type of the Gregorian calendar.
//
[System.Runtime.InteropServices.ComVisible(false)]
public override CalendarAlgorithmType AlgorithmType {
get { return CalendarAlgorithmType.SolarCalendar; }
}
/*=================================GetDefaultInstance==========================
**Action: Internal method to provide a default intance of GregorianCalendar. Used by NLS+ implementation
** and other calendars.
**Returns:
**Arguments:
**Exceptions:
============================================================================*/
static internal Calendar GetDefaultInstance()
{
if (m_defaultInstance == null) {
m_defaultInstance = new GregorianCalendar();
}
return (m_defaultInstance);
}
// Construct an instance of gregorian calendar.
public GregorianCalendar() : this(GregorianCalendarTypes.Localized)
{
}
public GregorianCalendar(GregorianCalendarTypes type)
{
if ((int)type < (int)GregorianCalendarTypes.Localized || (int)type > (int)GregorianCalendarTypes.TransliteratedFrench) {
throw new ArgumentOutOfRangeException("type", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), GregorianCalendarTypes.Localized, GregorianCalendarTypes.TransliteratedFrench));
}
this.m_type = type;
}
public virtual GregorianCalendarTypes CalendarType {
get { return (m_type); }
set {
VerifyWritable();
switch (value) {
case GregorianCalendarTypes.Localized:
case GregorianCalendarTypes.USEnglish:
case GregorianCalendarTypes.MiddleEastFrench:
case GregorianCalendarTypes.Arabic:
case GregorianCalendarTypes.TransliteratedEnglish:
case GregorianCalendarTypes.TransliteratedFrench:
m_type = value;
break;
default:
throw new ArgumentOutOfRangeException("m_type", Environment.GetResourceString("ArgumentOutOfRange_Enum"));
break;
}
}
}
internal override int ID {
// By returning different ID for different variations of GregorianCalendar,
// we can support the Transliterated Gregorian calendar.
// DateTimeFormatInfo will use this ID to get formatting information about
// the calendar.
get { return ((int)m_type); }
}
// Returns a given date part of this DateTime. This method is used
// to compute the year, day-of-year, month, or day part.
internal virtual int GetDatePart(long ticks, int part)
{
// n = number of days since 1/1/0001
int n = (int)(ticks / TicksPerDay);
// y400 = number of whole 400-year periods since 1/1/0001
int y400 = n / DaysPer400Years;
// n = day number within 400-year period
n -= y400 * DaysPer400Years;
// y100 = number of whole 100-year periods within 400-year period
int y100 = n / DaysPer100Years;
// Last 100-year period has an extra day, so decrement result if 4
if (y100 == 4)
y100 = 3;
// n = day number within 100-year period
n -= y100 * DaysPer100Years;
// y4 = number of whole 4-year periods within 100-year period
int y4 = n / DaysPer4Years;
// n = day number within 4-year period
n -= y4 * DaysPer4Years;
// y1 = number of whole years within 4-year period
int y1 = n / DaysPerYear;
// Last year has an extra day, so decrement result if 4
if (y1 == 4)
y1 = 3;
// If year was requested, compute and return it
if (part == DatePartYear) {
return (y400 * 400 + y100 * 100 + y4 * 4 + y1 + 1);
}
// n = day number within year
n -= y1 * DaysPerYear;
// If day-of-year was requested, return it
if (part == DatePartDayOfYear) {
return (n + 1);
}
// Leap year calculation looks different from IsLeapYear since y1, y4,
// and y100 are relative to year 1, not year 0
bool leapYear = (y1 == 3 && (y4 != 24 || y100 == 3));
int[] days = leapYear ? DaysToMonth366 : DaysToMonth365;
// All months have less than 32 days, so n >> 5 is a good conservative
// estimate for the month
int m = n >> 5 + 1;
// m = 1-based month number
while (n >= days[m])
m++;
// If month was requested, return it
if (part == DatePartMonth)
return (m);
// Return 1-based day-of-month
return (n - days[m - 1] + 1);
}
/*=================================GetAbsoluteDate==========================
**Action: Gets the absolute date for the given Gregorian date. The absolute date means
** the number of days from January 1st, 1 A.D.
**Returns: the absolute date
**Arguments:
** year the Gregorian year
** month the Gregorian month
** day the day
**Exceptions:
** ArgumentOutOfRangException if year, month, day value is valid.
**Note:
** This is an internal method used by DateToTicks() and the calculations of Hijri and Hebrew calendars.
** Number of Days in Prior Years (both common and leap years) +
** Number of Days in Prior Months of Current Year +
** Number of Days in Current Month
**
============================================================================*/
static internal long GetAbsoluteDate(int year, int month, int day)
{
if (year >= 1 && year <= MaxYear && month >= 1 && month <= 12) {
int[] days = ((year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))) ? DaysToMonth366 : DaysToMonth365;
if (day >= 1 && (day <= days[month] - days[month - 1])) {
int y = year - 1;
int absoluteDate = y * 365 + y / 4 - y / 100 + y / 400 + days[month - 1] + day - 1;
return (absoluteDate);
}
}
throw new ArgumentOutOfRangeException(null, Environment.GetResourceString("ArgumentOutOfRange_BadYearMonthDay"));
}
// Returns the tick count corresponding to the given year, month, and day.
// Will check the if the parameters are valid.
internal virtual long DateToTicks(int year, int month, int day)
{
return (GetAbsoluteDate(year, month, day) * TicksPerDay);
}
// 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("months", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), -120000, 120000));
}
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[] daysArray = (y % 4 == 0 && (y % 100 != 0 || y % 400 == 0)) ? DaysToMonth366 : DaysToMonth365;
int days = (daysArray[m] - daysArray[m - 1]);
if (d > days) {
d = days;
}
long ticks = DateToTicks(y, m, d) + 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));
}
// This is copied from the generic implementation of Calendar.cs. The generic implementation is not good enough
// in the case of FristFullWeek and FirstFourDayWeek since it needs the data for B.C. year 1 near 0001/1/1.
// We override the generic implementation to handle this special case.
[System.Runtime.InteropServices.ComVisible(false)]
public override int GetWeekOfYear(DateTime time, CalendarWeekRule rule, DayOfWeek firstDayOfWeek)
{
if ((int)firstDayOfWeek < 0 || (int)firstDayOfWeek > 6) {
throw new ArgumentOutOfRangeException("firstDayOfWeek", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), DayOfWeek.Sunday, DayOfWeek.Saturday));
}
switch (rule) {
case CalendarWeekRule.FirstDay:
return (GetFirstDayWeekOfYear(time, (int)firstDayOfWeek));
case CalendarWeekRule.FirstFullWeek:
return (InternalGetWeekOfYearFullDays(this, time, (int)firstDayOfWeek, 7, 365));
case CalendarWeekRule.FirstFourDayWeek:
return (InternalGetWeekOfYearFullDays(this, time, (int)firstDayOfWeek, 4, 365));
}
throw new ArgumentOutOfRangeException("rule", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), CalendarWeekRule.FirstDay, CalendarWeekRule.FirstFourDayWeek));
}
// This is copied from the generic implementation of GetWeekOfYearFullDays() in Calendar.cs. The generic implementation is not good enough
// in the case of FristFullWeek and FirstFourDayWeek since it needs the data for B.C. year 1 near 0001/1/1.
// We override the generic implementation to handle this special case.
// Parameters
//
static internal int InternalGetWeekOfYearFullDays(Calendar cal, DateTime time, int firstDayOfWeek, int fullDays, int daysOfMinYearMinusOne)
{
int dayForJan1;
int offset;
int day;
int dayOfYear = cal.GetDayOfYear(time) - 1;
// Make the day of year to be 0-based, so that 1/1 is day 0.
//
// Calculate the number of days between the first day of year (1/1) and the first day of the week.
// This value will be a positive value from 0 ~ 6. We call this value as "offset".
//
// If offset is 0, it means that the 1/1 is the start of the first week.
// Assume the first day of the week is Monday, it will look like this:
// Sun Mon Tue Wed Thu Fri Sat
// 12/31 1/1 1/2 1/3 1/4 1/5 1/6
// +--> First week starts here.
//
// If offset is 1, it means that the first day of the week is 1 day ahead of 1/1.
// Assume the first day of the week is Monday, it will look like this:
// Sun Mon Tue Wed Thu Fri Sat
// 1/1 1/2 1/3 1/4 1/5 1/6 1/7
// +--> First week starts here.
//
// If offset is 2, it means that the first day of the week is 2 days ahead of 1/1.
// Assume the first day of the week is Monday, it will look like this:
// Sat Sun Mon Tue Wed Thu Fri Sat
// 1/1 1/2 1/3 1/4 1/5 1/6 1/7 1/8
// +--> First week starts here.
// Day of week is 0-based.
// Get the day of week for 1/1. This can be derived from the day of week of the target day.
// Note that we can get a negative value. It's ok since we are going to make it a positive value when calculating the offset.
dayForJan1 = (int)cal.GetDayOfWeek(time) - (dayOfYear % 7);
// Now, calucalte the offset. Substract the first day of week from the dayForJan1. And make it a positive value.
offset = (firstDayOfWeek - dayForJan1 + 14) % 7;
if (offset != 0 && offset >= fullDays) {
//
// If the offset is greater than the value of fullDays, it means that
// the first week of the year starts on the week where Jan/1 falls on.
//
offset -= 7;
}
//
// Calculate the day of year for specified time by taking offset into account.
//
day = dayOfYear - offset;
if (day >= 0) {
//
// If the day of year value is greater than zero, get the week of year.
//
return (day / 7 + 1);
}
//
// Otherwise, the specified time falls on the week of previous year.
// Note that it is not always week 52 or 53, because it depends on the calendar. Different calendars have different number of days in a year.
//
// Repeat the previous calculation logic using the previous year and calculate the week of year for the last day of previous year.
int year = cal.GetYear(time);
if (year <= cal.GetYear(cal.MinSupportedDateTime)) {
// This specified time is in 0001/1/1 ~ 0001/1/7.
dayOfYear = daysOfMinYearMinusOne;
}
else {
dayOfYear = cal.GetDaysInYear(year - 1);
}
dayForJan1 = dayForJan1 - (dayOfYear % 7);
// Now, calucalte the offset. Substract the first day of week from the dayForJan1. And make it a positive value.
offset = (firstDayOfWeek - dayForJan1 + 14) % 7;
if (offset != 0 && offset >= fullDays) {
//
// If the offset is greater than the value of fullDays, it means that
// the first week of the year starts on the week where Jan/1 falls on.
//
offset -= 7;
}
//
// Calculate the day of year for specified time by taking offset into account.
//
day = dayOfYear - offset;
return (day / 7 + 1);
}
// 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.
//
public override int GetDaysInMonth(int year, int month, int era)
{
if (era == CurrentEra || era == ADEra) {
if (year < 1 || year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
if (month < 1 || month > 12) {
throw new ArgumentOutOfRangeException("month", Environment.GetResourceString("ArgumentOutOfRange_Month"));
}
int[] days = ((year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)) ? DaysToMonth366 : DaysToMonth365);
return (days[month] - days[month - 1]);
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
// 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)
{
if (era == CurrentEra || era == ADEra) {
if (year >= 1 && year <= MaxYear) {
return ((year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)) ? 366 : 365);
}
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
// Returns the era for the specified DateTime value.
public override int GetEra(DateTime time)
{
return (ADEra);
}
public override int[] Eras {
get { return (new int[] {ADEra}); }
}
// 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)
{
if (era == CurrentEra || era == ADEra) {
if (year >= 1 && year <= MaxYear) {
return (12);
}
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
// Returns the year part of the specified DateTime. The returned value is an
// integer between 1 and 9999.
//
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)
{
if (era != CurrentEra && era != ADEra) {
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
if (year < 1 || year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
if (month < 1 || month > 12) {
throw new ArgumentOutOfRangeException("month", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, 12));
}
if (day < 1 || day > GetDaysInMonth(year, month)) {
throw new ArgumentOutOfRangeException("day", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, GetDaysInMonth(year, month)));
}
if (!IsLeapYear(year)) {
return (false);
}
if (month == 2 && day == 29) {
return (true);
}
return (false);
}
// 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.
//
[System.Runtime.InteropServices.ComVisible(false)]
public override int GetLeapMonth(int year, int era)
{
if (era != CurrentEra && era != ADEra) {
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
if (year < 1 || year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
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)
{
if (era != CurrentEra && era != ADEra) {
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
if (year < 1 || year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
if (month < 1 || month > 12) {
throw new ArgumentOutOfRangeException("month", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, 12));
}
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)
{
if (era == CurrentEra || era == ADEra) {
if (year >= 1 && year <= MaxYear) {
return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
}
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
// 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)
{
if (era == CurrentEra || era == ADEra) {
return new DateTime(year, month, day, hour, minute, second, millisecond);
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
internal override bool TryToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era, out DateTime result)
{
if (era == CurrentEra || era == ADEra) {
return DateTime.TryCreate(year, month, day, hour, minute, second, millisecond, out result);
}
result = DateTime.MinValue;
return false;
}
private const int DEFAULT_TWO_DIGIT_YEAR_MAX = 2029;
public override int TwoDigitYearMax {
get {
if (twoDigitYearMax == -1) {
twoDigitYearMax = GetSystemTwoDigitYearSetting(ID, DEFAULT_TWO_DIGIT_YEAR_MAX);
}
return (twoDigitYearMax);
}
set {
VerifyWritable();
if (value < 99 || value > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 99, MaxYear));
}
twoDigitYearMax = value;
}
}
public override int ToFourDigitYear(int year)
{
if (year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
return (base.ToFourDigitYear(year));
}
}
}