internal static int GetDayOfWeek(LocalInstant localInstant)
{
// 1970-01-01 is day of week 4, Thursday.
unchecked
{
long daysSince19700101;
long ticks = localInstant.Ticks;
if (ticks >= 0)
{
daysSince19700101 = TickArithmetic.FastTicksToDays(ticks);
}
else
{
// Can't use TickArithmetic.TicksToDays here as we want to round down;
// division on negative numbers rounds towards zero, while shifting
// rounds down. The combination is awkward to think about for too long :)
daysSince19700101 = ((ticks >> 14) - 52734374) / 52734375;
if (daysSince19700101 < -3)
{
return(7 + (int)((daysSince19700101 + 4) % 7));
}
}
return(1 + (int)((daysSince19700101 + 3) % 7));
}
}
internal int GetDayOfYear(LocalInstant localInstant, int year)
{
long yearStart = GetStartOfYearInTicks(year);
unchecked
{
long ticksWithinYear = localInstant.Ticks - yearStart;
return(TickArithmetic.FastTicksToDays(ticksWithinYear) + 1);
}
}
protected int GetDayOfMonth(LocalInstant localInstant, int year, int month)
{
long dateTicks = GetYearMonthTicks(year, month);
unchecked
{
long ticksWithinMonth = localInstant.Ticks - dateTicks;
return(TickArithmetic.FastTicksToDays(ticksWithinMonth) + 1);
}
}
internal static long GetTickOfDay(LocalInstant localInstant)
{
// This is guaranteed not to overflow based on the operations we'll be performing.
unchecked
{
long ticks = localInstant.Ticks;
if (ticks >= 0)
{
// Surprisingly enough, this is faster than (but equivalent to)
// return ticks % NodaConstants.TicksPerStandardDay;
int days = TickArithmetic.FastTicksToDays(ticks);
return(ticks - ((days * 52734375L) << 14));
}
else
{
// I'm sure this can be optimized using shifting, but it's complicated enough as it is...
return((NodaConstants.TicksPerStandardDay - 1) + ((ticks + 1) % NodaConstants.TicksPerStandardDay));
}
}
}
/// <summary>
/// Converts a LocalInstant into an absolute day number.
/// </summary>
private static int AbsoluteDayFromLocalInstant(LocalInstant localInstant)
{
int daysSinceUnixEpoch = TickArithmetic.TicksToDays(localInstant.Ticks);
return(daysSinceUnixEpoch + AbsoluteDayOfUnixEpoch);
}
