System.TimeZoneInfo.GetDaylightChanges C# (CSharp) Method

		internal DaylightTime GetDaylightChanges (int year)
		{
			DateTime start = DateTime.MinValue, end = DateTime.MinValue;
			TimeSpan delta = new TimeSpan ();

			if (transitions != null) {
				end = DateTime.MaxValue;
				for (var i =  transitions.Count - 1; i >= 0; i--) {
					var pair = transitions [i];
					DateTime ttime = pair.Key;
					TimeType ttype = pair.Value;

					if (ttime.Year > year)
						continue;
					if (ttime.Year < year)
						break;

					if (ttype.IsDst) {
						// DaylightTime.Delta is relative to the current BaseUtcOffset.
						delta =  new TimeSpan (0, 0, ttype.Offset) - BaseUtcOffset;
						start = ttime;
					} else {
						end = ttime;
					}
				}

				// DaylightTime.Start is relative to the Standard time.
				if (!TryAddTicks (start, BaseUtcOffset.Ticks, out start))
					start = DateTime.MinValue;

				// DaylightTime.End is relative to the DST time.
				if (!TryAddTicks (end, BaseUtcOffset.Ticks + delta.Ticks, out end))
					end = DateTime.MinValue;
			} else {
				AdjustmentRule first = null, last = null;

				// Rule start/end dates are either very specific or very broad depending on the platform
				//   2015-10-04..2016-04-03 - Rule for a time zone in southern hemisphere on non-Windows platforms
				//   2016-03-27..2016-10-03 - Rule for a time zone in northern hemisphere on non-Windows platforms
				//   0001-01-01..9999-12-31 - Rule for a time zone on Windows

				foreach (var rule in GetAdjustmentRules ()) {
					if (rule.DateStart.Year > year || rule.DateEnd.Year < year)
						continue;
					if (rule.DateStart.Year <= year && (first == null || rule.DateStart.Year > first.DateStart.Year))
						first = rule;
					if (rule.DateEnd.Year >= year && (last == null || rule.DateEnd.Year < last.DateEnd.Year))
						last = rule;
				}

				if (first == null || last == null)
					return new DaylightTime (new DateTime (), new DateTime (), new TimeSpan ());

				start = TransitionPoint (first.DaylightTransitionStart, year);
				end = TransitionPoint (last.DaylightTransitionEnd, year);
				delta = first.DaylightDelta;
			}

			if (start == DateTime.MinValue || end == DateTime.MinValue)
				return new DaylightTime (new DateTime (), new DateTime (), new TimeSpan ());

			return new DaylightTime (start, end, delta);
		}

 public override System.Globalization.DaylightTime GetDaylightChanges(int year)
 {
     return(LocalTimeZone.GetDaylightChanges(year));
 }