/// <summary>
/// Adds the contents of this period to the given date and time, with the given scale (either 1 or -1, usually).
/// </summary>
internal LocalDateTime AddTo(LocalDate date, LocalTime time, int scalar)
{
date = AddTo(date, scalar);
int extraDays = 0;
time = TimePeriodField.Hours.Add(time, Hours * scalar, ref extraDays);
time = TimePeriodField.Minutes.Add(time, Minutes * scalar, ref extraDays);
time = TimePeriodField.Seconds.Add(time, Seconds * scalar, ref extraDays);
time = TimePeriodField.Milliseconds.Add(time, Milliseconds * scalar, ref extraDays);
time = TimePeriodField.Ticks.Add(time, Ticks * scalar, ref extraDays);
time = TimePeriodField.Nanoseconds.Add(time, Nanoseconds * scalar, ref extraDays);
// TODO(optimization): Investigate the performance impact of us calling PlusDays twice.
// Could optimize by including that in a single call...
return new LocalDateTime(date.PlusDays(extraDays), time);
}
/// <summary>
/// Returns the period between a start and an end date/time, using only the given units.
/// </summary>
/// <remarks>
/// If <paramref name="end"/> is before <paramref name="start" />, each property in the returned period
/// will be negative. If the given set of units cannot exactly reach the end point (e.g. finding
/// the difference between 1am and 3:15am in hours) the result will be such that adding it to <paramref name="start"/>
/// will give a value between <paramref name="start"/> and <paramref name="end"/>. In other words,
/// any rounding is "towards start"; this is true whether the resulting period is negative or positive.
/// </remarks>
/// <param name="start">Start date/time</param>
/// <param name="end">End date/time</param>
/// <param name="units">Units to use for calculations</param>
/// <exception cref="ArgumentException"><paramref name="units"/> is empty or contained unknown values.</exception>
/// <exception cref="ArgumentException"><paramref name="start"/> and <paramref name="end"/> use different calendars.</exception>
/// <returns>The period between the given date/times, using the given units.</returns>
public static Period Between(LocalDateTime start, LocalDateTime end, PeriodUnits units)
{
Preconditions.CheckArgument(units != 0, nameof(units), "Units must not be empty");
Preconditions.CheckArgument((units & ~PeriodUnits.AllUnits) == 0, nameof(units), "Units contains an unknown value: {0}", units);
CalendarSystem calendar = start.Calendar;
Preconditions.CheckArgument(calendar.Equals(end.Calendar), nameof(end), "start and end must use the same calendar system");
if (start == end)
{
return Zero;
}
// Adjust for situations like "days between 5th January 10am and 7th Janary 5am" which should be one
// day, because if we actually reach 7th January with date fields, we've overshot.
// The date adjustment will always be valid, because it's just moving it towards start.
// We need this for all date-based period fields. We could potentially optimize by not doing this
// in cases where we've only got time fields...
LocalDate endDate = end.Date;
if (start < end)
{
if (start.TimeOfDay > end.TimeOfDay)
{
endDate = endDate.PlusDays(-1);
}
}
else if (start > end && start.TimeOfDay < end.TimeOfDay)
{
endDate = endDate.PlusDays(1);
}
// Optimization for single field
switch (units)
{
case PeriodUnits.Years: return FromYears(DatePeriodFields.YearsField.UnitsBetween(start.Date, endDate));
case PeriodUnits.Months: return FromMonths(DatePeriodFields.MonthsField.UnitsBetween(start.Date, endDate));
case PeriodUnits.Weeks: return FromWeeks(DatePeriodFields.WeeksField.UnitsBetween(start.Date, endDate));
case PeriodUnits.Days: return FromDays(DaysBetween(start.Date, endDate));
case PeriodUnits.Hours: return FromHours(TimePeriodField.Hours.UnitsBetween(start, end));
case PeriodUnits.Minutes: return FromMinutes(TimePeriodField.Minutes.UnitsBetween(start, end));
case PeriodUnits.Seconds: return FromSeconds(TimePeriodField.Seconds.UnitsBetween(start, end));
case PeriodUnits.Milliseconds: return FromMilliseconds(TimePeriodField.Milliseconds.UnitsBetween(start, end));
case PeriodUnits.Ticks: return FromTicks(TimePeriodField.Ticks.UnitsBetween(start, end));
case PeriodUnits.Nanoseconds: return FromNanoseconds(TimePeriodField.Nanoseconds.UnitsBetween(start, end));
}
// Multiple fields
LocalDateTime remaining = start;
int years = 0, months = 0, weeks = 0, days = 0;
if ((units & PeriodUnits.AllDateUnits) != 0)
{
LocalDate remainingDate = DateComponentsBetween(
start.Date, endDate, units, out years, out months, out weeks, out days);
remaining = new LocalDateTime(remainingDate, start.TimeOfDay);
}
if ((units & PeriodUnits.AllTimeUnits) == 0)
{
return new Period(years, months, weeks, days);
}
// The remainder of the computation is with fixed-length units, so we can do it all with
// Duration instead of Local* values. We don't know for sure that this is small though - we *could*
// be trying to find the difference between 9998 BC and 9999 CE in nanoseconds...
// Where we can optimize, do everything with long arithmetic (as we do for Between(LocalTime, LocalTime)).
// Otherwise (rare case), use duration arithmetic.
long hours, minutes, seconds, milliseconds, ticks, nanoseconds;
var duration = end.ToLocalInstant().TimeSinceLocalEpoch - remaining.ToLocalInstant().TimeSinceLocalEpoch;
if (duration.IsInt64Representable)
{
TimeComponentsBetween(duration.ToInt64Nanoseconds(), units, out hours, out minutes, out seconds, out milliseconds, out ticks, out nanoseconds);
}
else
{
hours = UnitsBetween(PeriodUnits.Hours, TimePeriodField.Hours);
minutes = UnitsBetween(PeriodUnits.Minutes, TimePeriodField.Minutes);
seconds = UnitsBetween(PeriodUnits.Seconds, TimePeriodField.Seconds);
milliseconds = UnitsBetween(PeriodUnits.Milliseconds, TimePeriodField.Milliseconds);
ticks = UnitsBetween(PeriodUnits.Ticks, TimePeriodField.Ticks);
nanoseconds = UnitsBetween(PeriodUnits.Ticks, TimePeriodField.Nanoseconds);
}
return new Period(years, months, weeks, days, hours, minutes, seconds, milliseconds, ticks, nanoseconds);
long UnitsBetween(PeriodUnits mask, TimePeriodField timeField)
{
if ((mask & units) == 0)
{
return 0;
}
long value = timeField.GetUnitsInDuration(duration);
duration -= timeField.ToDuration(value);
return value;
}
}
/// <summary> /// Add days.<br /> /// 添加天数。 /// </summary> /// <param name="ld"></param> /// <param name="days"></param> /// <returns></returns> public static LocalDate AddDays(this LocalDate ld, int days) => ld.PlusDays(days);