// Converts an OLE Date to a tick count.
// This function is duplicated in COMDateTime.cpp
internal static long DoubleDateToTicks(double value)
{
// The check done this way will take care of NaN
if (!(value < OADateMaxAsDouble) || !(value > OADateMinAsDouble))
{
ExceptionThrower.ThrowArgumentException("OLE Date is invalid.", nameof(value));
}
// Conversion to long will not cause an overflow here, as at this point the "value" is in between OADateMinAsDouble and OADateMaxAsDouble
long millis = (long)(value * MillisPerDay + (value >= 0 ? 0.5 : -0.5));
// The interesting thing here is when you have a value like 12.5 it all positive 12 days and 12 hours from 01/01/1899
// However if you a value of -12.25 it is minus 12 days but still positive 6 hours, almost as though you meant -11.75 all negative
// This line below fixes up the millis in the negative case
if (millis < 0)
{
millis -= (millis % MillisPerDay) * 2;
}
millis += DoubleDateOffset / TicksPerMillisecond;
if (millis < 0 || millis >= MaxMillis)
{
ExceptionThrower.ThrowArgumentException("OLE Date scale is invalid.", nameof(value));
}
return(millis * TicksPerMillisecond);
}
// A version of ToBinary that uses the real representation and does not adjust local times. This is needed for
// scenarios where the serialized data must maintain compatibility
internal static Date FromBinaryRaw(long dateData)
{
long ticks = dateData & (long)TicksMask;
if (ticks < MinTicks || ticks > MaxTicks)
{
ExceptionThrower.ThrowArgumentException("Bad binary data.", nameof(dateData));
}
return(new Date((ulong)dateData));
}
//TODO: CHANGE TO NULLABLE IN C#8
public int CompareTo(object value)
{
if (value == null)
{
return(1);
}
if (!(value is Date))
{
ExceptionThrower.ThrowArgumentException("Must be a date.", nameof(value));
}
return(Compare(this, (Date)value));
}