コード例 #1
0
ファイル: DateAdd.cs プロジェクト: JeroenMX/TimePeriod
        protected DateTime?CalculateEnd(DateTime start, TimeSpan offset,
                                        SeekDirection seekDirection, SeekBoundaryMode seekBoundaryMode, out TimeSpan?remaining)
        {
            if (offset < TimeSpan.Zero)
            {
                throw new InvalidOperationException("time span must be positive");
            }

            remaining = offset;

            // search periods
            TimePeriodCollection searchPeriods = new TimePeriodCollection(_includePeriods);

            // no search periods specified: search anytime
            if (searchPeriods.Count == 0)
            {
                searchPeriods.Add(TimeRange.Anytime);
            }

            // available periods
            ITimePeriodCollection availablePeriods = new TimePeriodCollection();

            // no exclude periods specified: use all search periods
            if (_excludePeriods.Count == 0)
            {
                availablePeriods.AddAll(searchPeriods);
            }
            else             // remove exclude periods
            {
                TimeGapCalculator <TimeRange> gapCalculator = new TimeGapCalculator <TimeRange>();
                foreach (ITimePeriod searchPeriod in searchPeriods)
                {
                    // no overlaps: use the entire search range
                    if (!_excludePeriods.HasOverlapPeriods(searchPeriod))
                    {
                        availablePeriods.Add(searchPeriod);
                    }
                    else                     // add gaps of search period using the exclude periods
                    {
                        availablePeriods.AddAll(gapCalculator.GetGaps(_excludePeriods, searchPeriod));
                    }
                }
            }

            // no periods available
            if (availablePeriods.Count == 0)
            {
                return(null);
            }

            // combine the available periods, ensure no overlapping
            // used for FindNextPeriod/FindPreviousPeriod
            if (availablePeriods.Count > 1)
            {
                TimePeriodCombiner <TimeRange> periodCombiner = new TimePeriodCombiner <TimeRange>();
                availablePeriods = periodCombiner.CombinePeriods(availablePeriods);
            }

            // find the starting search period
            ITimePeriod startPeriod = null;
            DateTime    seekMoment  = start;

            switch (seekDirection)
            {
            case SeekDirection.Forward:
                startPeriod = FindNextPeriod(start, availablePeriods, out seekMoment);
                break;

            case SeekDirection.Backward:
                startPeriod = FindPreviousPeriod(start, availablePeriods, out seekMoment);
                break;
            }

            // no starting period available
            if (startPeriod == null)
            {
                return(null);
            }

            // no offset: use the search staring position
            // maybe moved to the next available search period
            if (offset == TimeSpan.Zero)
            {
                return(seekMoment);
            }

            // setup destination search
            switch (seekDirection)
            {
            case SeekDirection.Forward:
                for (int i = availablePeriods.IndexOf(startPeriod); i < availablePeriods.Count; i++)
                {
                    ITimePeriod gap         = availablePeriods[i];
                    TimeSpan    gapRemining = gap.End - seekMoment;

                    bool isTargetPeriod = false;
                    switch (seekBoundaryMode)
                    {
                    case SeekBoundaryMode.Fill:
                        isTargetPeriod = gapRemining >= remaining;
                        break;

                    case SeekBoundaryMode.Next:
                        isTargetPeriod = gapRemining > remaining;
                        break;
                    }

                    if (isTargetPeriod)
                    {
                        DateTime end = seekMoment + remaining.Value;
                        remaining = null;
                        return(end);
                    }

                    remaining = remaining - gapRemining;
                    if (i == availablePeriods.Count - 1)
                    {
                        return(null);
                    }
                    seekMoment = availablePeriods[i + 1].Start;                               // next period
                }
                break;

            case SeekDirection.Backward:
                for (int i = availablePeriods.IndexOf(startPeriod); i >= 0; i--)
                {
                    ITimePeriod gap         = availablePeriods[i];
                    TimeSpan    gapRemining = seekMoment - gap.Start;

                    bool isTargetPeriod = false;
                    switch (seekBoundaryMode)
                    {
                    case SeekBoundaryMode.Fill:
                        isTargetPeriod = gapRemining >= remaining;
                        break;

                    case SeekBoundaryMode.Next:
                        isTargetPeriod = gapRemining > remaining;
                        break;
                    }

                    if (isTargetPeriod)
                    {
                        DateTime end = seekMoment - remaining.Value;
                        remaining = null;
                        return(end);
                    }
                    remaining = remaining - gapRemining;
                    if (i == 0)
                    {
                        return(null);
                    }
                    seekMoment = availablePeriods[i - 1].End;                               // previous period
                }
                break;
            }

            return(null);
        }