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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
namespace System.Globalization {
using System;
using System.Runtime.CompilerServices;
using System.Globalization;
using System.Runtime.Versioning;
using System.Diagnostics.Contracts;
// This abstract class represents a calendar. A calendar reckons time in
// divisions such as weeks, months and years. The number, length and start of
// the divisions vary in each calendar.
//
// Any instant in time can be represented as an n-tuple of numeric values using
// a particular calendar. For example, the next vernal equinox occurs at (0.0, 0
// , 46, 8, 20, 3, 1999) in the Gregorian calendar. An implementation of
// Calendar can map any DateTime value to such an n-tuple and vice versa. The
// DateTimeFormat class can map between such n-tuples and a textual
// representation such as "8:46 AM Microsoft 20th 1999 AD".
//
// Most calendars identify a year which begins the current era. There may be any
// number of previous eras. The Calendar class identifies the eras as enumerated
// integers where the current era (CurrentEra) has the value zero.
//
// For consistency, the first unit in each interval, e.g. the first month, is
// assigned the value one.
// The calculation of hour/minute/second is moved to Calendar from GregorianCalendar,
// since most of the calendars (or all?) have the same way of calcuating hour/minute/second.
[Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class Calendar : ICloneable
{
// Number of 100ns (10E-7 second) ticks per time unit
internal const long TicksPerMillisecond = 10000;
internal const long TicksPerSecond = TicksPerMillisecond * 1000;
internal const long TicksPerMinute = TicksPerSecond * 60;
internal const long TicksPerHour = TicksPerMinute * 60;
internal const long TicksPerDay = TicksPerHour * 24;
// Number of milliseconds per time unit
internal const int MillisPerSecond = 1000;
internal const int MillisPerMinute = MillisPerSecond * 60;
internal const int MillisPerHour = MillisPerMinute * 60;
internal const int MillisPerDay = MillisPerHour * 24;
// Number of days in a non-leap year
internal const int DaysPerYear = 365;
// Number of days in 4 years
internal const int DaysPer4Years = DaysPerYear * 4 + 1;
// Number of days in 100 years
internal const int DaysPer100Years = DaysPer4Years * 25 - 1;
// Number of days in 400 years
internal const int DaysPer400Years = DaysPer100Years * 4 + 1;
// Number of days from 1/1/0001 to 1/1/10000
internal const int DaysTo10000 = DaysPer400Years * 25 - 366;
internal const long MaxMillis = (long)DaysTo10000 * MillisPerDay;
//
// Calendar ID Values. This is used to get data from calendar.nlp.
// The order of calendar ID means the order of data items in the table.
//
internal const int CAL_GREGORIAN = 1 ; // Gregorian (localized) calendar
internal const int CAL_GREGORIAN_US = 2 ; // Gregorian (U.S.) calendar
internal const int CAL_JAPAN = 3 ; // Japanese Emperor Era calendar
internal const int CAL_TAIWAN = 4 ; // Taiwan Era calendar
internal const int CAL_KOREA = 5 ; // Korean Tangun Era calendar
internal const int CAL_HIJRI = 6 ; // Hijri (Arabic Lunar) calendar
internal const int CAL_THAI = 7 ; // Thai calendar
internal const int CAL_HEBREW = 8 ; // Hebrew (Lunar) calendar
internal const int CAL_GREGORIAN_ME_FRENCH = 9 ; // Gregorian Middle East French calendar
internal const int CAL_GREGORIAN_ARABIC = 10; // Gregorian Arabic calendar
internal const int CAL_GREGORIAN_XLIT_ENGLISH = 11; // Gregorian Transliterated English calendar
internal const int CAL_GREGORIAN_XLIT_FRENCH = 12;
internal const int CAL_JULIAN = 13;
internal const int CAL_JAPANESELUNISOLAR = 14;
internal const int CAL_CHINESELUNISOLAR = 15;
internal const int CAL_SAKA = 16; // reserved to match Office but not implemented in our code
internal const int CAL_LUNAR_ETO_CHN = 17; // reserved to match Office but not implemented in our code
internal const int CAL_LUNAR_ETO_KOR = 18; // reserved to match Office but not implemented in our code
internal const int CAL_LUNAR_ETO_ROKUYOU = 19; // reserved to match Office but not implemented in our code
internal const int CAL_KOREANLUNISOLAR = 20;
internal const int CAL_TAIWANLUNISOLAR = 21;
internal const int CAL_PERSIAN = 22;
internal const int CAL_UMALQURA = 23;
internal int m_currentEraValue = -1;
[System.Runtime.Serialization.OptionalField(VersionAdded = 2)]
private bool m_isReadOnly = false;
// The minimum supported DateTime range for the calendar.
[System.Runtime.InteropServices.ComVisible(false)]
public virtual DateTime MinSupportedDateTime
{
get
{
return (DateTime.MinValue);
}
}
// The maximum supported DateTime range for the calendar.
[System.Runtime.InteropServices.ComVisible(false)]
public virtual DateTime MaxSupportedDateTime
{
get
{
return (DateTime.MaxValue);
}
}
protected Calendar() {
//Do-nothing constructor.
}
///
// This can not be abstract, otherwise no one can create a subclass of Calendar.
//
internal virtual int ID {
get {
return (-1);
}
}
///
// Return the Base calendar ID for calendars that didn't have defined data in calendarData
//
internal virtual int BaseCalendarID
{
get { return ID; }
}
// Returns the type of the calendar.
//
[System.Runtime.InteropServices.ComVisible(false)]
public virtual CalendarAlgorithmType AlgorithmType
{
get
{
return CalendarAlgorithmType.Unknown;
}
}
////////////////////////////////////////////////////////////////////////
//
// IsReadOnly
//
// Detect if the object is readonly.
//
////////////////////////////////////////////////////////////////////////
[System.Runtime.InteropServices.ComVisible(false)]
public bool IsReadOnly
{
get { return (m_isReadOnly); }
}
////////////////////////////////////////////////////////////////////////
//
// Clone
//
// Is the implementation of IColnable.
//
////////////////////////////////////////////////////////////////////////
[System.Runtime.InteropServices.ComVisible(false)]
public virtual Object Clone()
{
object o = MemberwiseClone();
((Calendar) o).SetReadOnlyState(false);
return (o);
}
////////////////////////////////////////////////////////////////////////
//
// ReadOnly
//
// Create a cloned readonly instance or return the input one if it is
// readonly.
//
////////////////////////////////////////////////////////////////////////
[System.Runtime.InteropServices.ComVisible(false)]
public static Calendar ReadOnly(Calendar calendar)
{
if (calendar == null) { throw new ArgumentNullException("calendar"); }
Contract.EndContractBlock();
if (calendar.IsReadOnly) { return (calendar); }
Calendar clonedCalendar = (Calendar)(calendar.MemberwiseClone());
clonedCalendar.SetReadOnlyState(true);
return (clonedCalendar);
}
internal void VerifyWritable()
{
if (m_isReadOnly)
{
throw new InvalidOperationException(Environment.GetResourceString("InvalidOperation_ReadOnly"));
}
}
internal void SetReadOnlyState(bool readOnly)
{
m_isReadOnly = readOnly;
}
/*=================================CurrentEraValue==========================
**Action: This is used to convert CurretEra(0) to an appropriate era value.
**Returns:
**Arguments:
**Exceptions:
**Notes:
** The value is from calendar.nlp.
============================================================================*/
internal virtual int CurrentEraValue {
get {
// The following code assumes that the current era value can not be -1.
if (m_currentEraValue == -1) {
Contract.Assert(BaseCalendarID > 0, "[Calendar.CurrentEraValue] Expected ID > 0");
m_currentEraValue = CalendarData.GetCalendarData(BaseCalendarID).iCurrentEra;
}
return (m_currentEraValue);
}
}
// The current era for a calendar.
public const int CurrentEra = 0;
internal int twoDigitYearMax = -1;
internal static void CheckAddResult(long ticks, DateTime minValue, DateTime maxValue) {
if (ticks < minValue.Ticks || ticks > maxValue.Ticks) {
throw new ArgumentException(
String.Format(CultureInfo.InvariantCulture, Environment.GetResourceString("Argument_ResultCalendarRange"),
minValue, maxValue));
}
Contract.EndContractBlock();
}
internal DateTime Add(DateTime time, double value, int scale) {
// From ECMA CLI spec, Partition III, section 3.27:
//
// If overflow occurs converting a floating-point type to an integer, or if the floating-point value
// being converted to an integer is a NaN, the value returned is unspecified.
//
// Based upon this, this method should be performing the comparison against the double
// before attempting a cast. Otherwise, the result is undefined.
double tempMillis = (value * scale + (value >= 0 ? 0.5 : -0.5));
if (!((tempMillis > -(double)MaxMillis) && (tempMillis < (double)MaxMillis)))
{
throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_AddValue"));
}
long millis = (long)tempMillis;
long ticks = time.Ticks + millis * TicksPerMillisecond;
CheckAddResult(ticks, MinSupportedDateTime, MaxSupportedDateTime);
return (new DateTime(ticks));
}
// Returns the DateTime resulting from adding the given number of
// milliseconds to the specified DateTime. The result is computed by rounding
// the number of milliseconds given by value to the nearest integer,
// and adding that interval to the specified DateTime. The value
// argument is permitted to be negative.
//
public virtual DateTime AddMilliseconds(DateTime time, double milliseconds) {
return (Add(time, milliseconds, 1));
}
// Returns the DateTime resulting from adding a fractional number of
// days to the specified DateTime. The result is computed by rounding the
// fractional number of days given by value to the nearest
// millisecond, and adding that interval to the specified DateTime. The
// value argument is permitted to be negative.
//
public virtual DateTime AddDays(DateTime time, int days) {
return (Add(time, days, MillisPerDay));
}
// Returns the DateTime resulting from adding a fractional number of
// hours to the specified DateTime. The result is computed by rounding the
// fractional number of hours given by value to the nearest
// millisecond, and adding that interval to the specified DateTime. The
// value argument is permitted to be negative.
//
public virtual DateTime AddHours(DateTime time, int hours) {
return (Add(time, hours, MillisPerHour));
}
// Returns the DateTime resulting from adding a fractional number of
// minutes to the specified DateTime. The result is computed by rounding the
// fractional number of minutes given by value to the nearest
// millisecond, and adding that interval to the specified DateTime. The
// value argument is permitted to be negative.
//
public virtual DateTime AddMinutes(DateTime time, int minutes) {
return (Add(time, minutes, MillisPerMinute));
}
// 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 abstract DateTime AddMonths(DateTime time, int months);
// Returns the DateTime resulting from adding a number of
// seconds to the specified DateTime. The result is computed by rounding the
// fractional number of seconds given by value to the nearest
// millisecond, and adding that interval to the specified DateTime. The
// value argument is permitted to be negative.
//
public virtual DateTime AddSeconds(DateTime time, int seconds) {
return Add(time, seconds, MillisPerSecond);
}
// Returns the DateTime resulting from adding a number of
// weeks to the specified DateTime. The
// value argument is permitted to be negative.
//
public virtual DateTime AddWeeks(DateTime time, int weeks) {
return (AddDays(time, weeks * 7));
}
// 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 abstract DateTime AddYears(DateTime time, int years);
// Returns the day-of-month part of the specified DateTime. The returned
// value is an integer between 1 and 31.
//
public abstract int GetDayOfMonth(DateTime time);
// 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 abstract DayOfWeek GetDayOfWeek(DateTime time);
// Returns the day-of-year part of the specified DateTime. The returned value
// is an integer between 1 and 366.
//
public abstract int GetDayOfYear(DateTime time);
// Returns the number of days in the month given by the year and
// month arguments.
//
public virtual int GetDaysInMonth(int year, int month)
{
return (GetDaysInMonth(year, month, CurrentEra));
}
// Returns the number of days in the month given by the year and
// month arguments for the specified era.
//
public abstract int GetDaysInMonth(int year, int month, int era);
// Returns the number of days in the year given by the year argument for the current era.
//
public virtual int GetDaysInYear(int year)
{
return (GetDaysInYear(year, CurrentEra));
}
// Returns the number of days in the year given by the year argument for the current era.
//
public abstract int GetDaysInYear(int year, int era);
// Returns the era for the specified DateTime value.
public abstract int GetEra(DateTime time);
/*=================================Eras==========================
**Action: Get the list of era values.
**Returns: The int array of the era names supported in this calendar.
** null if era is not used.
**Arguments: None.
**Exceptions: None.
============================================================================*/
public abstract int[] Eras {
get;
}
// Returns the hour part of the specified DateTime. The returned value is an
// integer between 0 and 23.
//
public virtual int GetHour(DateTime time) {
return ((int)((time.Ticks / TicksPerHour) % 24));
}
// Returns the millisecond part of the specified DateTime. The returned value
// is an integer between 0 and 999.
//
public virtual double GetMilliseconds(DateTime time) {
return (double)((time.Ticks / TicksPerMillisecond) % 1000);
}
// Returns the minute part of the specified DateTime. The returned value is
// an integer between 0 and 59.
//
public virtual int GetMinute(DateTime time) {
return ((int)((time.Ticks / TicksPerMinute) % 60));
}
// Returns the month part of the specified DateTime. The returned value is an
// integer between 1 and 12.
//
public abstract int GetMonth(DateTime time);
// Returns the number of months in the specified year in the current era.
public virtual int GetMonthsInYear(int year)
{
return (GetMonthsInYear(year, CurrentEra));
}
// Returns the number of months in the specified year and era.
public abstract int GetMonthsInYear(int year, int era);
// Returns the second part of the specified DateTime. The returned value is
// an integer between 0 and 59.
//
public virtual int GetSecond(DateTime time) {
return ((int)((time.Ticks / TicksPerSecond) % 60));
}
/*=================================GetFirstDayWeekOfYear==========================
**Action: Get the week of year using the FirstDay rule.
**Returns: the week of year.
**Arguments:
** time
** firstDayOfWeek the first day of week (0=Sunday, 1=Monday, ... 6=Saturday)
**Notes:
** The CalendarWeekRule.FirstDay rule: Week 1 begins on the first day of the year.
** Assume f is the specifed firstDayOfWeek,
** and n is the day of week for January 1 of the specified year.
** Assign offset = n - f;
** Case 1: offset = 0
** E.g.
** f=1
** weekday 0 1 2 3 4 5 6 0 1
** date 1/1
** week# 1 2
** then week of year = (GetDayOfYear(time) - 1) / 7 + 1
**
** Case 2: offset < 0
** e.g.
** n=1 f=3
** weekday 0 1 2 3 4 5 6 0
** date 1/1
** week# 1 2
** This means that the first week actually starts 5 days before 1/1.
** So week of year = (GetDayOfYear(time) + (7 + offset) - 1) / 7 + 1
** Case 3: offset > 0
** e.g.
** f=0 n=2
** weekday 0 1 2 3 4 5 6 0 1 2
** date 1/1
** week# 1 2
** This means that the first week actually starts 2 days before 1/1.
** So Week of year = (GetDayOfYear(time) + offset - 1) / 7 + 1
============================================================================*/
internal int GetFirstDayWeekOfYear(DateTime time, int firstDayOfWeek) {
int dayOfYear = GetDayOfYear(time) - 1; // Make the day of year to be 0-based, so that 1/1 is day 0.
// Calculate the day of week for the first day of the year.
// dayOfWeek - (dayOfYear % 7) is the day of week for the first day of this year. Note that
// this value can be less than 0. It's fine since we are making it positive again in calculating offset.
int dayForJan1 = (int)GetDayOfWeek(time) - (dayOfYear % 7);
int offset = (dayForJan1 - firstDayOfWeek + 14) % 7;
Contract.Assert(offset >= 0, "Calendar.GetFirstDayWeekOfYear(): offset >= 0");
return ((dayOfYear + offset) / 7 + 1);
}
private int GetWeekOfYearFullDays(DateTime time, int firstDayOfWeek, int fullDays) {
int dayForJan1;
int offset;
int day;
int dayOfYear = 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)GetDayOfWeek(time) - (dayOfYear % 7);
// Now, calculate the offset. Subtract 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.
// Call this method again by passing the last day of previous year.
//
// the last day of the previous year may "underflow" to no longer be a valid date time for
// this calendar if we just subtract so we need the subclass to provide us with
// that information
if (time <= MinSupportedDateTime.AddDays(dayOfYear))
{
return GetWeekOfYearOfMinSupportedDateTime(firstDayOfWeek, fullDays);
}
return (GetWeekOfYearFullDays(time.AddDays(-(dayOfYear + 1)), firstDayOfWeek, fullDays));
}
private int GetWeekOfYearOfMinSupportedDateTime(int firstDayOfWeek, int minimumDaysInFirstWeek)
{
int dayOfYear = GetDayOfYear(MinSupportedDateTime) - 1; // Make the day of year to be 0-based, so that 1/1 is day 0.
int dayOfWeekOfFirstOfYear = (int)GetDayOfWeek(MinSupportedDateTime) - dayOfYear % 7;
// Calculate the offset (how many days from the start of the year to the start of the week)
int offset = (firstDayOfWeek + 7 - dayOfWeekOfFirstOfYear) % 7;
if (offset == 0 || offset >= minimumDaysInFirstWeek)
{
// First of year falls in the first week of the year
return 1;
}
int daysInYearBeforeMinSupportedYear = DaysInYearBeforeMinSupportedYear - 1; // Make the day of year to be 0-based, so that 1/1 is day 0.
int dayOfWeekOfFirstOfPreviousYear = dayOfWeekOfFirstOfYear - 1 - (daysInYearBeforeMinSupportedYear % 7);
// starting from first day of the year, how many days do you have to go forward
// before getting to the first day of the week?
int daysInInitialPartialWeek = (firstDayOfWeek - dayOfWeekOfFirstOfPreviousYear + 14) % 7;
int day = daysInYearBeforeMinSupportedYear - daysInInitialPartialWeek;
if (daysInInitialPartialWeek >= minimumDaysInFirstWeek)
{
// If the offset is greater than the minimum Days in the first week, it means that
// First of year is part of the first week of the year even though it is only a partial week
// add another week
day += 7;
}
return (day / 7 + 1);
}
// it would be nice to make this abstract but we can't since that would break previous implementations
protected virtual int DaysInYearBeforeMinSupportedYear
{
get
{
return 365;
}
}
// Returns the week of year for the specified DateTime. The returned value is an
// integer between 1 and 53.
//
public virtual int GetWeekOfYear(DateTime time, CalendarWeekRule rule, DayOfWeek firstDayOfWeek)
{
if ((int)firstDayOfWeek < 0 || (int)firstDayOfWeek > 6) {
throw new ArgumentOutOfRangeException(
"firstDayOfWeek", Environment.GetResourceString("ArgumentOutOfRange_Range",
DayOfWeek.Sunday, DayOfWeek.Saturday));
}
Contract.EndContractBlock();
switch (rule) {
case CalendarWeekRule.FirstDay:
return (GetFirstDayWeekOfYear(time, (int)firstDayOfWeek));
case CalendarWeekRule.FirstFullWeek:
return (GetWeekOfYearFullDays(time, (int)firstDayOfWeek, 7));
case CalendarWeekRule.FirstFourDayWeek:
return (GetWeekOfYearFullDays(time, (int)firstDayOfWeek, 4));
}
throw new ArgumentOutOfRangeException(
"rule", Environment.GetResourceString("ArgumentOutOfRange_Range",
CalendarWeekRule.FirstDay, CalendarWeekRule.FirstFourDayWeek));
}
// Returns the year part of the specified DateTime. The returned value is an
// integer between 1 and 9999.
//
public abstract int GetYear(DateTime time);
// Checks whether a given day in the current era is a leap day. This method returns true if
// the date is a leap day, or false if not.
//
public virtual bool IsLeapDay(int year, int month, int day)
{
return (IsLeapDay(year, month, day, CurrentEra));
}
// 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 abstract bool IsLeapDay(int year, int month, int day, int era);
// Checks whether a given month in the current era is a leap month. This method returns true if
// month is a leap month, or false if not.
//
public virtual bool IsLeapMonth(int year, int month) {
return (IsLeapMonth(year, month, CurrentEra));
}
// 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 abstract bool IsLeapMonth(int year, int month, int era);
// Returns the leap month in a calendar year of the current 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 virtual int GetLeapMonth(int year)
{
return (GetLeapMonth(year, CurrentEra));
}
// 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 virtual int GetLeapMonth(int year, int era)
{
if (!IsLeapYear(year, era))
return 0;
int monthsCount = GetMonthsInYear(year, era);
for (int month=1; month<=monthsCount; month++)
{
if (IsLeapMonth(year, month, era))
return month;
}
return 0;
}
// Checks whether a given year in the current era is a leap year. This method returns true if
// year is a leap year, or false if not.
//
public virtual bool IsLeapYear(int year)
{
return (IsLeapYear(year, CurrentEra));
}
// 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 abstract bool IsLeapYear(int year, int era);
// Returns the date and time converted to a DateTime value. Throws an exception if the n-tuple is invalid.
//
public virtual DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond)
{
return (ToDateTime(year, month, day, hour, minute, second, millisecond, CurrentEra));
}
// Returns the date and time converted to a DateTime value. Throws an exception if the n-tuple is invalid.
//
public abstract DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era);
internal virtual Boolean TryToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era, out DateTime result) {
result = DateTime.MinValue;
try {
result = ToDateTime(year, month, day, hour, minute, second, millisecond, era);
return true;
}
catch (ArgumentException) {
return false;
}
}
internal virtual bool IsValidYear(int year, int era) {
return (year >= GetYear(MinSupportedDateTime) && year <= GetYear(MaxSupportedDateTime));
}
internal virtual bool IsValidMonth(int year, int month, int era) {
return (IsValidYear(year, era) && month >= 1 && month <= GetMonthsInYear(year, era));
}
internal virtual bool IsValidDay(int year, int month, int day, int era)
{
return (IsValidMonth(year, month, era) && day >= 1 && day <= GetDaysInMonth(year, month, era));
}
// Returns and assigns the maximum value to represent a two digit year. This
// value is the upper boundary of a 100 year range that allows a two digit year
// to be properly translated to a four digit year. For example, if 2029 is the
// upper boundary, then a two digit value of 30 should be interpreted as 1930
// while a two digit value of 29 should be interpreted as 2029. In this example
// , the 100 year range would be from 1930-2029. See ToFourDigitYear().
public virtual int TwoDigitYearMax
{
get
{
return (twoDigitYearMax);
}
set
{
VerifyWritable();
twoDigitYearMax = value;
}
}
// Converts the year value to the appropriate century by using the
// TwoDigitYearMax property. For example, if the TwoDigitYearMax value is 2029,
// then a two digit value of 30 will get converted to 1930 while a two digit
// value of 29 will get converted to 2029.
public virtual int ToFourDigitYear(int year) {
if (year < 0) {
throw new ArgumentOutOfRangeException("year",
Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
Contract.EndContractBlock();
if (year < 100) {
return ((TwoDigitYearMax/100 - ( year > TwoDigitYearMax % 100 ? 1 : 0))*100 + year);
}
// If the year value is above 100, just return the year value. Don't have to do
// the TwoDigitYearMax comparison.
return (year);
}
// Return the tick count corresponding to the given hour, minute, second.
// Will check the if the parameters are valid.
internal static long TimeToTicks(int hour, int minute, int second, int millisecond)
{
if (hour >= 0 && hour < 24 && minute >= 0 && minute < 60 && second >=0 && second < 60)
{
if (millisecond < 0 || millisecond >= MillisPerSecond) {
throw new ArgumentOutOfRangeException(
"millisecond",
String.Format(
CultureInfo.InvariantCulture,
Environment.GetResourceString("ArgumentOutOfRange_Range"), 0, MillisPerSecond - 1));
}
return TimeSpan.TimeToTicks(hour, minute, second) + millisecond * TicksPerMillisecond;
}
throw new ArgumentOutOfRangeException(null, Environment.GetResourceString("ArgumentOutOfRange_BadHourMinuteSecond"));
}
[System.Security.SecuritySafeCritical] // auto-generated
[ResourceExposure(ResourceScope.None)]
[ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
internal static int GetSystemTwoDigitYearSetting(int CalID, int defaultYearValue)
{
// Call nativeGetTwoDigitYearMax
int twoDigitYearMax = CalendarData.nativeGetTwoDigitYearMax(CalID);
if (twoDigitYearMax < 0)
{
twoDigitYearMax = defaultYearValue;
}
return (twoDigitYearMax);
}
}
}
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