/// <summary>
/// This is used to find the next instance of the monthly frequency
/// </summary>
/// <param name="r">A reference to the recurrence</param>
/// <param name="end">The recurrence end date</param>
/// <param name="to">The end date of the range limiting the instances generated</param>
/// <param name="last">This is used to pass in the last instance date calculated and return the next
/// instance date</param>
/// <returns>True if the recurrence has another instance or false if there are no more instances</returns>
public bool FindNext(Recurrence r, RecurDateTime end, RecurDateTime to, RecurDateTime last)
{
last.AddMonths(r.Interval);
if (RecurDateTime.Compare(last, end, RecurDateTime.DateTimePart.Month) > 0 ||
RecurDateTime.Compare(last, to, RecurDateTime.DateTimePart.Month) > 0)
{
return(false);
}
return(true);
}
/// <summary>
/// This is used to expand by month day
/// </summary>
/// <param name="r">A reference to the recurrence</param>
/// <param name="dates">A reference to the collection of current instances that have been generated</param>
/// <returns>The number of instances in the collection. If zero, subsequent rules don't have to be
/// checked as there's nothing else to do.</returns>
/// <remarks>If an expanded date is invalid, it will be discarded</remarks>
public static int ByMonthDay(Recurrence r, RecurDateTimeCollection dates)
{
RecurDateTime rdt, rdtNew;
int expIdx, monthDay, count = dates.Count;
UniqueIntegerCollection byMonthDay = r.ByMonthDay;
// Don't bother if either collection is empty
if (count != 0 && byMonthDay.Count != 0)
{
for (int idx = 0; idx < count; idx++)
{
rdt = dates[0];
dates.RemoveAt(0);
// Expand the date/time by adding a new entry for each month day specified
for (expIdx = 0; expIdx < byMonthDay.Count; expIdx++)
{
monthDay = byMonthDay[expIdx];
rdtNew = new RecurDateTime(rdt);
rdtNew.Day = 1;
// From start of month or end of month?
if (monthDay > 0)
{
rdtNew.AddDays(monthDay - 1);
}
else
{
rdtNew.AddMonths(1);
rdtNew.AddDays(monthDay);
}
// If not in the month, discard it
if (rdtNew.Month != rdt.Month)
{
continue;
}
dates.Add(rdtNew);
}
}
}
return(dates.Count);
}
/// <summary>
/// This is used to find the starting point for the monthly frequency
/// </summary>
/// <param name="r">A reference to the recurrence</param>
/// <param name="start">The recurrence start date</param>
/// <param name="end">The recurrence end date</param>
/// <param name="from">The start date of the range limiting the instances generated</param>
/// <param name="to">The end date of the range limiting the instances generated</param>
/// <returns>The first instance date or null if there are no more instances</returns>
public RecurDateTime FindStart(Recurrence r, RecurDateTime start, RecurDateTime end, RecurDateTime from,
RecurDateTime to)
{
int adjust;
RecurDateTime rdt = new RecurDateTime(start);
// Adjust the date if the starting date is before the limiting range start date
if (RecurDateTime.Compare(rdt, from, RecurDateTime.DateTimePart.Month) < 0)
{
adjust = ((from.Year - rdt.Year) * 12) + from.Month - rdt.Month + r.Interval - 1;
rdt.AddMonths(adjust - (adjust % r.Interval));
}
if (RecurDateTime.Compare(rdt, end, RecurDateTime.DateTimePart.Month) > 0 ||
RecurDateTime.Compare(rdt, to, RecurDateTime.DateTimePart.Month) > 0)
{
return(null);
}
return(rdt);
}
