/// <summary>
/// Gets the dates.
/// </summary>
/// <param name="seed">The seed.</param>
/// <param name="periodStart">The period start.</param>
/// <param name="periodEnd">The period end.</param>
/// <param name="maxCount">The max count.</param>
/// <param name="pattern">The pattern.</param>
/// <param name="includeReferenceDateInResults">
/// if set to <c>true</c> [include reference date in results].
/// </param>
/// <returns></returns>
private IEnumerable <DateTime> GetDates(IDateTime seed, DateTime periodStart, DateTime periodEnd, int maxCount, IRecurrencePattern pattern, bool includeReferenceDateInResults)
{
var dates = new List <DateTime>( );
DateTime originalDate = DateUtil.GetSimpleDateTimeData(seed);
DateTime seedCopy = DateUtil.GetSimpleDateTimeData(seed);
if (includeReferenceDateInResults)
{
dates.Add(seedCopy);
}
// If the interval is set to zero, or our count prevents us
// from getting additional items, then return with the reference
// date only.
if (pattern.Interval == 0 ||
(pattern.Count != int.MinValue && pattern.Count <= dates.Count))
{
return(dates);
}
// optimize the start time for selecting candidates
// (only applicable where a COUNT is not specified)
if (pattern.Count == int.MinValue)
{
DateTime incremented = seedCopy;
// FIXME: we can more aggressively increment here when
// the difference between dates is greater.
IncrementDate(ref incremented, pattern, pattern.Interval);
while (incremented < periodStart)
{
seedCopy = incremented;
IncrementDate(ref incremented, pattern, pattern.Interval);
}
}
bool?[] expandBehavior = RecurrenceUtil.GetExpandBehaviorList(pattern);
int invalidCandidateCount = 0;
int noCandidateIncrementCount = 0;
DateTime candidate = DateTime.MinValue;
while ((maxCount < 0) || (dates.Count < maxCount))
{
if (pattern.Until != DateTime.MinValue && candidate != DateTime.MinValue && candidate > pattern.Until)
{
break;
}
if (candidate != DateTime.MinValue && candidate > periodEnd)
{
break;
}
if (pattern.Count >= 1 && (dates.Count + invalidCandidateCount) >= pattern.Count)
{
break;
}
List <DateTime> candidates = GetCandidates(seedCopy, pattern, expandBehavior);
if (candidates.Count > 0)
{
noCandidateIncrementCount = 0;
// sort candidates for identifying when UNTIL date is exceeded..
candidates.Sort( );
foreach (DateTime t in candidates)
{
candidate = t;
// don't count candidates that occur before the original date..
if (candidate >= originalDate)
{
// candidates MAY occur before periodStart
// For example, FREQ=YEARLY;BYWEEKNO=1 could return dates
// from the previous year.
//
// candidates exclusive of periodEnd..
if (candidate >= periodEnd)
{
invalidCandidateCount++;
}
else if (pattern.Count >= 1 && (dates.Count + invalidCandidateCount) >= pattern.Count)
{
break;
}
else if (pattern.Until == DateTime.MinValue || candidate <= pattern.Until)
{
if (!dates.Contains(candidate))
{
dates.Add(candidate);
}
}
}
}
}
else
{
noCandidateIncrementCount++;
if ((noCandidateIncrementCount > MaxIncrementCount))
{
break;
}
}
IncrementDate(ref seedCopy, pattern, pattern.Interval);
}
// sort final list..
dates.Sort( );
return(dates);
}
