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

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
{
using System.Threading;
using System;
/*=================================EraInfo==========================
**
** This is the structure to store information about an era.
**
============================================================================*/
[Serializable()]
internal class EraInfo
{
internal int era;
// The value of the era.
internal long ticks;
// The time in ticks when the era starts
internal int yearOffset;
// The offset to Gregorian year when the era starts.
// Gregorian Year = Era Year + yearOffset
// Era Year = Gregorian Year - yearOffset
internal int minEraYear;
// Min year value in this era. Generally, this value is 1, but this may
// be affected by the DateTime.MinValue;
internal int maxEraYear;
// Max year value in this era. (== the year length of the era + 1)
internal EraInfo(int era, long ticks, int yearOffset, int minEraYear, int maxEraYear)
{
this.era = era;
this.ticks = ticks;
this.yearOffset = yearOffset;
this.minEraYear = minEraYear;
this.maxEraYear = maxEraYear;
}
}
//
// 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)
[Serializable()]
internal class GregorianCalendarHelper
{
// 1 tick = 100ns = 10E-7 second
// Number of 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;
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 int MaxYear {
get { return (m_maxYear); }
}
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};
internal int m_maxYear = 9999;
internal int m_minYear;
internal Calendar m_Cal;
internal EraInfo[] m_EraInfo;
internal int[] m_eras = null;
// m_minDate is existing here just to keep the serialization compatibility.
// it has nothing to do with the code anymore.
internal DateTime m_minDate;
/*=================================InitEraInfo==========================
**Action: Get the era range information from calendar.nlp.
**Returns: An array of EraInfo, which contains the information about an era.
**Arguments:
** calID the Calendar ID defined in Calendar.cs
============================================================================*/
static internal EraInfo[] InitEraInfo(int calID)
{
//
// Initialize era information.
//
/*
Japaense era info example:
eraInfo[0] = new EraInfo(4, new DateTime(1989, 1, 8).Ticks, 1988, 1, GregorianCalendar.MaxYear - 1988); // Heisei. Most recent
eraInfo[1] = new EraInfo(3, new DateTime(1926, 12, 25).Ticks, 1925, 1, 1989 - 1925); // Showa
eraInfo[2] = new EraInfo(2, new DateTime(1912, 7, 30).Ticks, 1911, 1, 1926 - 1911); // Taisho
eraInfo[3] = new EraInfo(1, new DateTime(1868, 9, 8).Ticks, 1867, 1, 1912 - 1867); // Meiji
*/
BCLDebug.Assert(calID > 0, "[GregorianCalendarHelper.InitEraInfo] Expected calID > 0");
int[][] eraRanges = CalendarTable.Default.SERARANGES(calID);
EraInfo[] eraInfo = new EraInfo[eraRanges.Length];
int maxEraYear = GregorianCalendar.MaxYear;
for (int i = 0; i < eraRanges.Length; i++) {
//
// The eraRange arrays are each the form of "4 1989 1 8 1988 1".
// eraRanges[i][0] is the era value.
// eraRanges[i][1] is the year when the era starts.
// eraRanges[i][2] is the month when the era starts.
// eraRanges[i][3] is the day when the era starts.
// eraRanges[i][4] is the offset to Gregorian year (1988).
// eraRanges[i][5] is the minimum era year for this era.
//
BCLDebug.Assert(eraRanges[i].Length == 6, "[GregorianCalendarHelper.InitEraInfo] Expected 6 SERARANGE elements (0-5), not " + eraRanges[i].Length);
eraInfo[i] = new EraInfo(eraRanges[i][0], new DateTime(eraRanges[i][1], eraRanges[i][2], eraRanges[i][3]).Ticks, eraRanges[i][4], eraRanges[i][5], maxEraYear - eraRanges[i][4]);
maxEraYear = eraRanges[i][1];
}
return (eraInfo);
}
// Construct an instance of gregorian calendar.
internal GregorianCalendarHelper(Calendar cal, EraInfo[] eraInfo)
{
m_Cal = cal;
m_EraInfo = eraInfo;
// m_minDate is existing here just to keep the serialization compatibility.
// it has nothing to do with the code anymore.
m_minDate = m_Cal.MinSupportedDateTime;
m_maxYear = m_EraInfo[0].maxEraYear;
m_minYear = m_EraInfo[0].minEraYear;
;
}
/*=================================GetGregorianYear==========================
**Action: Get the Gregorian year value for the specified year in an era.
**Returns: The Gregorian year value.
**Arguments:
** year the year value in Japanese calendar
** era the Japanese emperor era value.
**Exceptions:
** ArgumentOutOfRangeException if year value is invalid or era value is invalid.
============================================================================*/
internal int GetGregorianYear(int year, int era)
{
if (year < 0) {
throw new ArgumentOutOfRangeException("year", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
}
if (era == Calendar.CurrentEra) {
era = m_Cal.CurrentEraValue;
}
for (int i = 0; i < m_EraInfo.Length; i++) {
if (era == m_EraInfo[i].era) {
if (year < m_EraInfo[i].minEraYear || year > m_EraInfo[i].maxEraYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), m_EraInfo[i].minEraYear, m_EraInfo[i].maxEraYear));
}
return (m_EraInfo[i].yearOffset + year);
}
}
throw new ArgumentOutOfRangeException("era", Environment.GetResourceString("ArgumentOutOfRange_InvalidEraValue"));
}
internal bool IsValidYear(int year, int era)
{
if (year < 0) {
return false;
}
if (era == Calendar.CurrentEra) {
era = m_Cal.CurrentEraValue;
}
for (int i = 0; i < m_EraInfo.Length; i++) {
if (era == m_EraInfo[i].era) {
if (year < m_EraInfo[i].minEraYear || year > m_EraInfo[i].maxEraYear) {
return false;
}
return true;
}
}
return false;
}
// 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)
{
CheckTicksRange(ticks);
// 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 <= 9999 && 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.
static internal long DateToTicks(int year, int month, int day)
{
return (GetAbsoluteDate(year, month, day) * TicksPerDay);
}
// Return the tick count corresponding to the given hour, minute, second.
// Will check the if the parameters are valid.
static internal long TimeToTicks(int hour, int minute, int second, int millisecond)
{
//TimeSpan.TimeToTicks is a family access function which does no error checking, so
//we need to put some error checking out here.
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.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 0, MillisPerSecond - 1));
}
return (TimeSpan.TimeToTicks(hour, minute, second) + millisecond * TicksPerMillisecond);
;
}
throw new ArgumentOutOfRangeException(null, Environment.GetResourceString("ArgumentOutOfRange_BadHourMinuteSecond"));
}
internal void CheckTicksRange(long ticks)
{
if (ticks < m_Cal.MinSupportedDateTime.Ticks || ticks > m_Cal.MaxSupportedDateTime.Ticks) {
throw new ArgumentOutOfRangeException("time", String.Format(CultureInfo.InvariantCulture, Environment.GetResourceString("ArgumentOutOfRange_CalendarRange"), m_Cal.MinSupportedDateTime, m_Cal.MaxSupportedDateTime));
}
}
// 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 DateTime AddMonths(DateTime time, int months)
{
CheckTicksRange(time.Ticks);
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, m_Cal.MinSupportedDateTime, m_Cal.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 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 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 DayOfWeek GetDayOfWeek(DateTime time)
{
CheckTicksRange(time.Ticks);
return ((DayOfWeek)((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 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 int GetDaysInMonth(int year, int month, int era)
{
//
// Convert year/era value to Gregorain year value.
//
year = GetGregorianYear(year, era);
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]);
}
// Returns the number of days in the year given by the year argument for the current era.
//
public int GetDaysInYear(int year, int era)
{
//
// Convert year/era value to Gregorain year value.
//
year = GetGregorianYear(year, era);
return ((year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)) ? 366 : 365);
}
// Returns the era for the specified DateTime value.
public int GetEra(DateTime time)
{
long ticks = time.Ticks;
// The assumption here is that m_EraInfo is listed in reverse order.
for (int i = 0; i < m_EraInfo.Length; i++) {
if (ticks >= m_EraInfo[i].ticks) {
return (m_EraInfo[i].era);
}
}
throw new ArgumentOutOfRangeException(Environment.GetResourceString("ArgumentOutOfRange_Era"));
}
public int[] Eras {
get {
if (m_eras == null) {
m_eras = new int[m_EraInfo.Length];
for (int i = 0; i < m_EraInfo.Length; i++) {
m_eras[i] = m_EraInfo[i].era;
}
}
return ((int[])m_eras.Clone());
}
}
// Returns the month part of the specified DateTime. The returned value is an
// integer between 1 and 12.
//
public int GetMonth(DateTime time)
{
return (GetDatePart(time.Ticks, DatePartMonth));
}
// Returns the number of months in the specified year and era.
public int GetMonthsInYear(int year, int era)
{
year = GetGregorianYear(year, era);
return (12);
}
// Returns the year part of the specified DateTime. The returned value is an
// integer between 1 and 9999.
//
public int GetYear(DateTime time)
{
long ticks = time.Ticks;
int year = GetDatePart(ticks, DatePartYear);
for (int i = 0; i < m_EraInfo.Length; i++) {
if (ticks >= m_EraInfo[i].ticks) {
return (year - m_EraInfo[i].yearOffset);
}
}
throw new ArgumentException(Environment.GetResourceString("Argument_NoEra"));
}
// Returns the year that match the specified Gregorian year. The returned value is an
// integer between 1 and 9999.
//
public int GetYear(int year, DateTime time)
{
long ticks = time.Ticks;
for (int i = 0; i < m_EraInfo.Length; i++) {
if (ticks >= m_EraInfo[i].ticks) {
return (year - m_EraInfo[i].yearOffset);
}
}
throw new ArgumentException(Environment.GetResourceString("Argument_NoEra"));
}
// 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 bool IsLeapDay(int year, int month, int day, int era)
{
// year/month/era checking is done in GetDaysInMonth()
if (day < 1 || day > GetDaysInMonth(year, month, era)) {
throw new ArgumentOutOfRangeException("day", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), 1, GetDaysInMonth(year, month, era)));
}
if (!IsLeapYear(year, era)) {
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.
//
public int GetLeapMonth(int year, int era)
{
year = GetGregorianYear(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 bool IsLeapMonth(int year, int month, int era)
{
year = GetGregorianYear(year, era);
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 bool IsLeapYear(int year, int era)
{
year = GetGregorianYear(year, era);
return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
}
// Returns the date and time converted to a DateTime value. Throws an exception if the n-tuple is invalid.
//
public DateTime ToDateTime(int year, int month, int day, int hour, int minute, int second, int millisecond, int era)
{
year = GetGregorianYear(year, era);
long ticks = DateToTicks(year, month, day) + TimeToTicks(hour, minute, second, millisecond);
CheckTicksRange(ticks);
return (new DateTime(ticks));
}
public virtual int GetWeekOfYear(DateTime time, CalendarWeekRule rule, DayOfWeek firstDayOfWeek)
{
CheckTicksRange(time.Ticks);
// Use GregorianCalendar to get around the problem that the implmentation in Calendar.GetWeekOfYear()
// can call GetYear() that exceeds the supported range of the Gregorian-based calendars.
return (GregorianCalendar.GetDefaultInstance().GetWeekOfYear(time, rule, firstDayOfWeek));
}
public int ToFourDigitYear(int year, int twoDigitYearMax)
{
if (year < 0) {
throw new ArgumentOutOfRangeException("year", Environment.GetResourceString("ArgumentOutOfRange_NeedPosNum"));
}
if (year < 100) {
int y = year % 100;
return ((twoDigitYearMax / 100 - (y > twoDigitYearMax % 100 ? 1 : 0)) * 100 + y);
}
if (year < m_minYear || year > m_maxYear) {
throw new ArgumentOutOfRangeException("year", String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("ArgumentOutOfRange_Range"), m_minYear, m_maxYear));
}
// If the year value is above 100, just return the year value. Don't have to do
// the TwoDigitYearMax comparison.
return (year);
}
}
}