public static CalendarDateTime Subtract(CalendarDateTime x, CalendarDateTimeDuration y)
{
long year = x.Year - y.Years;
double month = x.Month - y.Months;
double day = x.Day - y.Days;
double hour = x.Hour - y.Hours;
double minute = x.Minute;
double second = x.Second;
TimePrecision precision = x.Precision;
if (y.Minutes != null)
{
minute -= y.Minutes.Value;
if (minute != (int)minute && precision > TimePrecision.Minute)
{
second += (minute - (int)minute) * SecondsPerMinute;
minute = (int)minute;
}
if (precision < TimePrecision.Minute)
{
precision = TimePrecision.Minute;
}
}
if (y.Seconds != null)
{
second -= y.Seconds.Value;
if (precision < TimePrecision.Second)
{
precision = TimePrecision.Second;
}
}
while (second <= -SecondsPerMinute)
{
second += SecondsPerMinute;
minute--;
}
while (minute <= -MinutesPerHour)
{
minute += MinutesPerHour;
hour--;
}
while (hour <= -HoursPerDay)
{
hour += HoursPerDay;
day--;
}
while (month < 1)
{
month += MonthsPerYear;
year--;
}
while (day < 1)
{
day += DaysInMonth(year, (int)month);
month--;
}
switch (precision)
{
case TimePrecision.Hour:
return new CalendarDateTime(new CalendarDate(year, (int)month, (int)day), new Time(hour));
case TimePrecision.Minute:
return new CalendarDateTime(new CalendarDate(year, (int)month, (int)day), new Time((int)hour, minute));
case TimePrecision.Second:
return new CalendarDateTime(new CalendarDate(year, (int)month, (int)day), new Time((int)hour, (int)minute, second));
default:
return null;
}
}
public static CalendarDateTime Add(CalendarDateTime x, CalendarDateTimeDuration y)
{
double day = x.Day + y.Days;
double month = x.Month + y.Months;
double year = x.Year + y.Years;
var second = x.Second;
var minute = x.Minute;
var hour = x.Hour + y.Hours;
var precision = x.Precision;
if (y.Minutes != null)
{
minute += y.Minutes.Value;
if (hour != (int)hour)
{
minute += (hour - (int)hour) * MinutesPerHour;
}
if (precision < TimePrecision.Minute)
{
precision = TimePrecision.Minute;
}
}
if (y.Seconds != null)
{
second += y.Seconds.Value;
if (minute != (int)minute)
{
second += (minute - (int)minute) * SecondsPerMinute;
}
if (precision < TimePrecision.Second)
{
precision = TimePrecision.Second;
}
}
while (!(second < SecondsPerMinute))
{
second -= SecondsPerMinute;
minute++;
}
while ((int)minute >= MinutesPerHour)
{
minute -= MinutesPerHour;
hour++;
}
while ((int)hour >= HoursPerDay)
{
hour -= HoursPerDay;
day++;
}
while ((int)month > MonthsPerYear)
{
month -= MonthsPerYear;
year++;
}
int daysInMonth = DaysInMonth((long)year, (int)month);
while (day > daysInMonth)
{
day -= daysInMonth;
month++;
daysInMonth = DaysInMonth((long)year, (int)month);
}
switch (precision)
{
case TimePrecision.Hour:
return new CalendarDateTime(new CalendarDate((long)year, (int)month, (int)day), new Time(hour));
case TimePrecision.Minute:
return new CalendarDateTime(new CalendarDate((long)year, (int)month, (int)day), new Time((int)hour, minute));
case TimePrecision.Second:
return new CalendarDateTime(new CalendarDate((long)year, (int)month, (int)day), new Time((int)hour, (int)minute, second));
default:
return null;
}
}
