/// <summary>
/// Equivalent to <see cref="Instant.SafePlus"/>, but in the opposite direction.
/// </summary>
internal Instant SafeMinus(Offset offset)
{
int days = duration.FloorDays;
// If we can do the arithmetic safely, do so.
if (days > Instant.MinDays && days < Instant.MaxDays)
{
return(Minus(offset));
}
// Handle BeforeMinValue and BeforeMaxValue simply.
if (days < Instant.MinDays)
{
return(Instant.BeforeMinValue);
}
if (days > Instant.MaxDays)
{
return(Instant.AfterMaxValue);
}
// Okay, do the arithmetic as a Duration, then check the result for overflow, effectively.
var asDuration = duration.PlusSmallNanoseconds(offset.Nanoseconds);
if (asDuration.FloorDays < Instant.MinDays)
{
return(Instant.BeforeMinValue);
}
if (asDuration.FloorDays > Instant.MaxDays)
{
return(Instant.AfterMaxValue);
}
return(new Instant(asDuration));
}
internal LocalInstant Plus(Offset offset) => new LocalInstant(duration.PlusSmallNanoseconds(offset.Nanoseconds));
