DateTime DateTime::operator-(const DateTimeSpan& dateSpan) const
{
DateTime dateResult; // Initializes status_ to valid
// If either operand NULL, result NULL
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateResult.SetStatus(null);
return dateResult;
}
// If either operand invalid, result invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateResult.SetStatus(invalid);
return dateResult;
}
// Compute the actual date difference by subtracting underlying dates
dateResult = DateFromDouble(DoubleFromDate(dt_) - dateSpan.span_);
// Validate within range
dateResult.CheckRange();
return dateResult;
}
DateTimeSpan DateTimeSpan::operator-(const DateTimeSpan& dateSpan)
const
{
DateTimeSpan dateSpanTemp;
// If either operand Null, result Null
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateSpanTemp.SetStatus(null);
return dateSpanTemp;
}
// If either operand Invalid, result Invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateSpanTemp.SetStatus(invalid);
return dateSpanTemp;
}
// Subtract spans and validate within legal range
dateSpanTemp.span_ = span_ - dateSpan.span_;
dateSpanTemp.CheckRange();
return dateSpanTemp;
}
DateTimeSpan DateTimeSpan::operator+(const DateTimeSpan& dateSpan)
const
{
DateTimeSpan dateSpanTemp;
// If either operand Null, result Null
if (GetStatus() == null || dateSpan.GetStatus() == null)
{
dateSpanTemp.SetStatus(null);
return dateSpanTemp;
}
// If either operand Invalid, result Invalid
if (GetStatus() == invalid || dateSpan.GetStatus() == invalid)
{
dateSpanTemp.SetStatus(invalid);
return dateSpanTemp;
}
// Add spans and validate within legal range
dateSpanTemp.m_span = m_span + dateSpan.m_span;
dateSpanTemp.CheckRange();
return dateSpanTemp;
}