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

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// ==++==
//
//
//
// 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
{
using System;
//
// This class implements the Julian calendar. In 48 B.C. Julius Caesar ordered a calendar reform, and this calendar
// is called Julian calendar. It consisted of a solar year of twelve months and of 365 days with an extra day
// every fourth year.
//*
//* Calendar support range:
//* Calendar Minimum Maximum
//* ========== ========== ==========
//* Gregorian 0001/01/01 9999/12/31
//* Julia 0001/01/03 9999/10/19
[Serializable()]
[System.Runtime.InteropServices.ComVisible(true)]
public class JulianCalendar : Calendar
{
public static readonly int JulianEra = 1;
private const int DatePartYear = 0;
private const int DatePartDayOfYear = 1;
private const int DatePartMonth = 2;
private const int DatePartDay = 3;
// Number of days in a non-leap year
private const int JulianDaysPerYear = 365;
// Number of days in 4 years
private const int JulianDaysPer4Years = JulianDaysPerYear * 4 + 1;
//internal static Calendar m_defaultInstance;
private static readonly int[] DaysToMonth365 = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273,
304, 334, 365};
private static readonly int[] DaysToMonth366 = {0, 31, 60, 91, 121, 152, 182, 213, 244, 274,
305, 335, 366};
// Gregorian Calendar 9999/12/31 = Julian Calendar 9999/10/19
// keep it as variable field for serialization compat.
internal int MaxYear = 9999;
[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 Julian calendar.
//
[System.Runtime.InteropServices.ComVisible(false)]
public override CalendarAlgorithmType AlgorithmType {
get { return CalendarAlgorithmType.SolarCalendar; }
}
/*=================================GetDefaultInstance==========================
**Action: Internal method to provide a default intance of JulianCalendar. Used by NLS+ implementation
** and other calendars.
**Returns:
**Arguments:
**Exceptions:
============================================================================*/
/*
internal static Calendar GetDefaultInstance() {
if (m_defaultInstance == null) {
m_defaultInstance = new JulianCalendar();
}
return (m_defaultInstance);
}
*/
// Construct an instance of gregorian calendar.
public JulianCalendar()
{
// There is no system setting of TwoDigitYear max, so set the value here.
twoDigitYearMax = 2029;
}
internal override int ID {
get { return (CAL_JULIAN); }
}
internal void CheckEraRange(int era)
{
if (era != CurrentEra && era != JulianEra) {
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
}
internal void CheckYearEraRange(int year, int era)
{
CheckEraRange(era);
if (year <= 0 || year > MaxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, MaxYear));
}
}
internal void CheckMonthRange(int month)
{
if (month < 1 || month > 12) {
throw new ArgumentOutOfRangeException("month", Environment.GetResourceString("ArgumentOutOfRange_Month"));
}
}
/*=================================GetDefaultInstance==========================
**Action: Check for if the day value is valid.
**Returns:
**Arguments:
**Exceptions:
**Notes:
** Before calling this method, call CheckYearEraRange()/CheckMonthRange() to make
** sure year/month values are correct.
============================================================================*/
internal void CheckDayRange(int year, int month, int day)
{
if (year == 1 && month == 1) {
// The mimimum supported Julia date is Julian 0001/01/03.
if (day < 3) {
throw new ArgumentOutOfRangeException(null, Environment.GetResourceString("ArgumentOutOfRange_BadYearMonthDay"));
}
}
bool isLeapYear = (year % 4) == 0;
int[] days = isLeapYear ? DaysToMonth366 : DaysToMonth365;
int monthDays = days[month] - days[month - 1];
if (day < 1 || day > monthDays) {
throw new ArgumentOutOfRangeException("day", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, monthDays));
}
}
// Returns a given date part of this DateTime. This method is used
// to compute the year, day-of-year, month, or day part.
internal int GetDatePart(long ticks, int part)
{
// Gregorian 1/1/0001 is Julian 1/3/0001. Remember DateTime(0) is refered to Gregorian 1/1/0001.
// The following line convert Gregorian ticks to Julian ticks.
long julianTicks = ticks + TicksPerDay * 2;
// n = number of days since 1/1/0001
int n = (int)(julianTicks / TicksPerDay);
// y4 = number of whole 4-year periods within 100-year period
int y4 = n / JulianDaysPer4Years;
// n = day number within 4-year period
n -= y4 * JulianDaysPer4Years;
// y1 = number of whole years within 4-year period
int y1 = n / JulianDaysPerYear;
// 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 (y4 * 4 + y1 + 1);
}
// n = day number within year
n -= y1 * JulianDaysPerYear;
// 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);
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);
}
// Returns the tick count corresponding to the given year, month, and day.
internal long DateToTicks(int year, int month, int day)
{
int[] days = (year % 4 == 0) ? DaysToMonth366 : DaysToMonth365;
int y = year - 1;
int n = y * 365 + y / 4 + days[month - 1] + day - 1;
// Gregorian 1/1/0001 is Julian 1/3/0001. n * TicksPerDay is the ticks in JulianCalendar.
// Therefore, we subtract two days in the following to convert the ticks in JulianCalendar
// to ticks in Gregorian calendar.
return ((n - 2) * TicksPerDay);
}
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));
}
public override DateTime AddYears(DateTime time, int years)
{
return (AddMonths(time, years * 12));
}
public override int GetDayOfMonth(DateTime time)
{
return (GetDatePart(time.Ticks, DatePartDay));
}
public override DayOfWeek GetDayOfWeek(DateTime time)
{
return ((DayOfWeek)((int)(time.Ticks / TicksPerDay + 1) % 7));
}
public override int GetDayOfYear(DateTime time)
{
return (GetDatePart(time.Ticks, DatePartDayOfYear));
}
public override int GetDaysInMonth(int year, int month, int era)
{
CheckYearEraRange(year, era);
CheckMonthRange(month);
int[] days = (year % 4 == 0) ? DaysToMonth366 : DaysToMonth365;
return (days[month] - days[month - 1]);
}
public override int GetDaysInYear(int year, int era)
{
// Year/Era range is done in IsLeapYear().
return (IsLeapYear(year, era) ? 366 : 365);
}
public override int GetEra(DateTime time)
{
return (JulianEra);
}
public override int GetMonth(DateTime time)
{
return (GetDatePart(time.Ticks, DatePartMonth));
}
public override int[] Eras {
get { return (new int[] {JulianEra}); }
}
public override int GetMonthsInYear(int year, int era)
{
CheckYearEraRange(year, era);
return (12);
}
public override int GetYear(DateTime time)
{
return (GetDatePart(time.Ticks, DatePartYear));
}
public override bool IsLeapDay(int year, int month, int day, int era)
{
CheckMonthRange(month);
// Year/Era range check is done in IsLeapYear().
if (IsLeapYear(year, era)) {
CheckDayRange(year, month, day);
return (month == 2 && day == 29);
}
CheckDayRange(year, month, day);
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)
{
CheckYearEraRange(year, era);
return (0);
}
public override bool IsLeapMonth(int year, int month, int era)
{
CheckYearEraRange(year, era);
CheckMonthRange(month);
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)
{
CheckYearEraRange(year, era);
return (year % 4 == 0);
}
public override DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era)
{
CheckYearEraRange(year, era);
CheckMonthRange(month);
CheckDayRange(year, month, day);
if (millisecond < 0 || millisecond >= MillisPerSecond) {
throw new ArgumentOutOfRangeException("millisecond", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 0, MillisPerSecond - 1));
}
if (hour >= 0 && hour < 24 && minute >= 0 && minute < 60 && second >= 0 && second < 60) {
return new DateTime(DateToTicks(year, month, day) + (new TimeSpan(0, hour, minute, second, millisecond)).Ticks);
}
else {
throw new ArgumentOutOfRangeException(null, Environment.GetResourceString("ArgumentOutOfRange_BadHourMinuteSecond"));
}
}
public override int TwoDigitYearMax {
get { 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_Bounds_Lower_Upper"), 1, MaxYear));
}
return (base.ToFourDigitYear(year));
}
}
}