/// <summary>
/// Creates a new <see cref="BclDateTimeZone" /> from a <see cref="TimeZoneInfo"/> from the Base Class Library.
/// </summary>
/// <param name="bclZone">The original time zone to take information from.</param>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the given <c>TimeZoneInfo</c>.</returns>
public static BclDateTimeZone FromTimeZoneInfo(TimeZoneInfo bclZone)
{
Preconditions.CheckNotNull(bclZone, nameof(bclZone));
Offset standardOffset = bclZone.BaseUtcOffset.ToOffset();
var rules = bclZone.GetAdjustmentRules();
if (!bclZone.SupportsDaylightSavingTime || rules.Length == 0)
{
var fixedInterval = new ZoneInterval(bclZone.StandardName, Instant.BeforeMinValue, Instant.AfterMaxValue, standardOffset, Offset.Zero);
return(new BclDateTimeZone(bclZone, new SingleZoneIntervalMap(fixedInterval)));
}
BclAdjustmentRule[] convertedRules;
if (AreWindowsStyleRules(rules))
{
convertedRules = Array.ConvertAll(rules, rule => BclAdjustmentRule.FromWindowsAdjustmentRule(bclZone, rule));
}
else
{
convertedRules = Array.ConvertAll(rules, rule => BclAdjustmentRule.FromUnixAdjustmentRule(bclZone, rule));
FixUnixTransitions(convertedRules);
}
IZoneIntervalMap uncachedMap = BuildMap(convertedRules, standardOffset, bclZone.StandardName);
IZoneIntervalMap cachedMap = CachingZoneIntervalMap.CacheMap(uncachedMap);
return(new BclDateTimeZone(bclZone, cachedMap));
}
/// <summary>
/// Gets the zone offset period for the given instant.
/// </summary>
/// <param name="instant">The Instant to find.</param>
/// <returns>The ZoneInterval including the given instant.</returns>
public override ZoneInterval GetZoneInterval(Instant instant)
{
if (tailZone != null && instant >= tailZoneStart)
{
// Clamp the tail zone interval to start at the end of our final period, if necessary, so that the
// join is seamless.
ZoneInterval intervalFromTailZone = tailZone.GetZoneInterval(instant);
return(intervalFromTailZone.RawStart < tailZoneStart ? firstTailZoneInterval : intervalFromTailZone);
}
int lower = 0; // Inclusive
int upper = periods.Length; // Exclusive
while (lower < upper)
{
int current = (lower + upper) / 2;
var candidate = periods[current];
if (candidate.RawStart > instant)
{
upper = current;
}
// Safe to use RawEnd, as it's just for the comparison.
else if (candidate.RawEnd <= instant)
{
lower = current + 1;
}
else
{
return(candidate);
}
}
// Note: this would indicate a bug. The time zone is meant to cover the whole of time.
throw new InvalidOperationException($"Instant {instant} did not exist in time zone {Id}");
}
private IEnumerable <ZoneInterval> CoalesceIntervals(IEnumerable <ZoneInterval> zoneIntervals)
{
ZoneInterval current = null;
foreach (var zoneInterval in zoneIntervals)
{
if (current == null)
{
current = zoneInterval;
continue;
}
if (zoneIntervalComparer.EqualExceptStartAndEnd(current, zoneInterval))
{
current = current.WithEnd(zoneInterval.RawEnd);
}
else
{
yield return(current);
current = zoneInterval;
}
}
// current will only be null if start == end...
if (current != null)
{
yield return(current);
}
}
/// <summary>
/// Reads a time zone from the specified reader.
/// </summary>
/// <param name="reader">The reader.</param>
/// <param name="id">The id.</param>
/// <returns>The time zone.</returns>
public static DateTimeZone ReadLegacy(LegacyDateTimeZoneReader reader, string id)
{
string[] stringPool = new string[reader.ReadCount()];
for (int i = 0; i < stringPool.Length; i++)
{
stringPool[i] = reader.ReadString();
}
int size = reader.ReadCount();
var periods = new ZoneInterval[size];
var start = reader.ReadZoneIntervalTransition(null);
for (int i = 0; i < size; i++)
{
int nameIndex = stringPool.Length < 256 ? reader.ReadByte() : reader.ReadInt32();
var name = stringPool[nameIndex];
var offset = reader.ReadOffset();
var savings = reader.ReadOffset();
var nextStart = reader.ReadZoneIntervalTransition(start);
periods[i] = new ZoneInterval(name, start, nextStart, offset, savings);
start = nextStart;
}
var tailZone = reader.ReadTimeZone(id + "-tail");
return(new PrecalculatedDateTimeZone(id, periods, tailZone));
}
/// <summary>
/// Creates a new <see cref="BclDateTimeZone" /> from a <see cref="TimeZoneInfo"/> from the Base Class Library.
/// </summary>
/// <param name="bclZone">The original time zone to take information from.</param>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the given <c>TimeZoneInfo</c>.</returns>
public static BclDateTimeZone FromTimeZoneInfo(TimeZoneInfo bclZone)
{
Preconditions.CheckNotNull(bclZone, nameof(bclZone));
Offset standardOffset = bclZone.BaseUtcOffset.ToOffset();
var rules = bclZone.GetAdjustmentRules();
if (!bclZone.SupportsDaylightSavingTime || rules.Length == 0)
{
var fixedInterval = new ZoneInterval(bclZone.StandardName, Instant.BeforeMinValue, Instant.AfterMaxValue, standardOffset, Offset.Zero);
return(new BclDateTimeZone(bclZone, standardOffset, standardOffset, new SingleZoneIntervalMap(fixedInterval)));
}
int windowsRules = rules.Count(IsWindowsRule);
var ruleConverter = AreWindowsStyleRules(rules)
? rule => BclAdjustmentRule.FromWindowsAdjustmentRule(bclZone, rule)
: (Converter <TimeZoneInfo.AdjustmentRule, BclAdjustmentRule>)(rule => BclAdjustmentRule.FromUnixAdjustmentRule(bclZone, rule));
BclAdjustmentRule[] convertedRules = Array.ConvertAll(rules, ruleConverter);
Offset minRuleOffset = convertedRules.Aggregate(Offset.MaxValue, (min, rule) => Offset.Min(min, rule.Savings + rule.StandardOffset));
Offset maxRuleOffset = convertedRules.Aggregate(Offset.MinValue, (min, rule) => Offset.Max(min, rule.Savings + rule.StandardOffset));
IZoneIntervalMap uncachedMap = BuildMap(convertedRules, standardOffset, bclZone.StandardName);
IZoneIntervalMap cachedMap = CachingZoneIntervalMap.CacheMap(uncachedMap);
return(new BclDateTimeZone(bclZone, Offset.Min(standardOffset, minRuleOffset), Offset.Max(standardOffset, maxRuleOffset), cachedMap));
}
internal ZoneLocalMapping(DateTimeZone zone, LocalDateTime localDateTime, ZoneInterval earlyInterval, ZoneInterval lateInterval, int count)
{
this.zone = Preconditions.CheckNotNull(zone, "zone");
this.localDateTime = localDateTime;
this.earlyInterval = Preconditions.CheckNotNull(earlyInterval, "earlyInterval");
this.lateInterval = Preconditions.CheckNotNull(lateInterval, "lateInterval");
Preconditions.CheckArgumentRange("count", count, 0, 2);
this.count = count;
}
internal ZoneLocalMapping([Trusted][NotNull] DateTimeZone zone, LocalDateTime localDateTime,
[Trusted][NotNull] ZoneInterval earlyInterval, [Trusted][NotNull] ZoneInterval lateInterval, int count)
{
Preconditions.DebugCheckNotNull(zone, nameof(zone));
Preconditions.DebugCheckNotNull(earlyInterval, nameof(earlyInterval));
Preconditions.DebugCheckNotNull(lateInterval, nameof(lateInterval));
Preconditions.DebugCheckArgumentRange(nameof(count), count, 0, 2);
this.Zone = zone;
this.EarlyInterval = earlyInterval;
this.LateInterval = lateInterval;
this.LocalDateTime = localDateTime;
this.Count = count;
}
internal PrecalculatedDateTimeZone([NotNull] string id, [NotNull] ZoneInterval[] intervals, IZoneIntervalMapWithMinMax tailZone)
: base(id, false,
ComputeOffset(intervals, tailZone, Offset.Min),
ComputeOffset(intervals, tailZone, Offset.Max))
{
this.periods = intervals;
this.tailZone = tailZone;
this.tailZoneStart = intervals[intervals.Length - 1].RawEnd; // We want this to be AfterMaxValue for tail-less zones.
if (tailZone != null)
{
// Cache a "clamped" zone interval for use at the start of the tail zone.
firstTailZoneInterval = tailZone.GetZoneInterval(tailZoneStart).WithStart(tailZoneStart);
}
ValidatePeriods(intervals, tailZone);
}
/// <summary>
/// Initializes a new instance of the <see cref="PrecalculatedDateTimeZone"/> class.
/// This is only visible to make testing simpler.
/// </summary>
/// <param name="id">The id.</param>
/// <param name="periods">The periods.</param>
/// <param name="tailZone">The tail zone.</param>
internal PrecalculatedDateTimeZone(string id, ZoneInterval[] periods, DateTimeZone tailZone)
: base(id, false,
ComputeOffset(periods, p => p.WallOffset, tailZone, Offset.Min),
ComputeOffset(periods, p => p.WallOffset, tailZone, Offset.Max))
{
this.tailZone = tailZone;
this.periods = periods;
this.tailZone = tailZone;
this.tailZoneStart = periods[periods.Length - 1].End;
if (tailZone != null)
{
// Cache a "clamped" zone interval for use at the start of the tail zone.
firstTailZoneInterval = tailZone.GetZoneInterval(tailZoneStart).WithStart(tailZoneStart);
}
ValidatePeriods(periods, tailZone);
}
/// <summary>
/// Creates a hash table node with all the information for this period.
/// We start off by finding the interval for the start of the period, and
/// then repeatedly check whether that interval ends after the end of the
/// period - at which point we're done. If not, find the next interval, create
/// a new node referring to that interval and the previous interval, and keep going.
/// </summary>
internal static HashCacheNode CreateNode(int period, IZoneIntervalMap map)
{
var periodStart = new Instant((long)period << PeriodShift);
var periodEnd = new Instant((long)(period + 1) << PeriodShift);
var interval = map.GetZoneInterval(periodStart);
var node = new HashCacheNode(interval, period, null);
// Keep going while the current interval ends before the period.
while (interval.End < periodEnd)
{
interval = map.GetZoneInterval(interval.End);
node = new HashCacheNode(interval, period, node);
}
return(node);
}
/// <summary>
/// Reads a time zone from the specified reader.
/// </summary>
/// <param name="reader">The reader.</param>
/// <param name="id">The id.</param>
/// <returns>The time zone.</returns>
public static DateTimeZone Read(IDateTimeZoneReader reader, string id)
{
int size = reader.ReadCount();
var periods = new ZoneInterval[size];
var start = reader.ReadZoneIntervalTransition(null);
for (int i = 0; i < size; i++)
{
var name = reader.ReadString();
var offset = reader.ReadOffset();
var savings = reader.ReadOffset();
var nextStart = reader.ReadZoneIntervalTransition(start);
periods[i] = new ZoneInterval(name, start, nextStart, offset, savings);
start = nextStart;
}
var tailZone = reader.ReadByte() == 1 ? DaylightSavingsDateTimeZone.Read(reader, id + "-tail") : null;
return(new PrecalculatedDateTimeZone(id, periods, tailZone));
}
/// <summary>
/// Creates a new <see cref="BclDateTimeZone" /> from a <see cref="TimeZoneInfo"/> from the Base Class Library.
/// </summary>
/// <param name="bclZone">The original time zone to take information from.</param>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the given <c>TimeZoneInfo</c>.</returns>
[NotNull] public static BclDateTimeZone FromTimeZoneInfo([NotNull] TimeZoneInfo bclZone)
{
Preconditions.CheckNotNull(bclZone, nameof(bclZone));
Offset standardOffset = bclZone.BaseUtcOffset.ToOffset();
var rules = bclZone.GetAdjustmentRules();
if (!bclZone.SupportsDaylightSavingTime || rules.Length == 0)
{
var fixedInterval = new ZoneInterval(bclZone.StandardName, Instant.BeforeMinValue, Instant.AfterMaxValue, standardOffset, Offset.Zero);
return(new BclDateTimeZone(bclZone, standardOffset, standardOffset, new SingleZoneIntervalMap(fixedInterval)));
}
BclAdjustmentRule[] convertedRules = Array.ConvertAll(rules, rule => new BclAdjustmentRule(bclZone, rule));
Offset minRuleOffset = convertedRules.Aggregate(Offset.MaxValue, (min, rule) => Offset.Min(min, rule.Savings + rule.StandardOffset));
Offset maxRuleOffset = convertedRules.Aggregate(Offset.MinValue, (min, rule) => Offset.Max(min, rule.Savings + rule.StandardOffset));
IZoneIntervalMap uncachedMap = BuildMap(convertedRules, standardOffset, bclZone.StandardName);
IZoneIntervalMap cachedMap = CachingZoneIntervalMap.CacheMap(uncachedMap, CachingZoneIntervalMap.CacheType.Hashtable);
return(new BclDateTimeZone(bclZone, Offset.Min(standardOffset, minRuleOffset), Offset.Max(standardOffset, maxRuleOffset), cachedMap));
}
/// <summary>
/// Gets the zone offset period for the given instant.
/// </summary>
/// <param name="instant">The Instant to find.</param>
/// <returns>The ZoneInterval including the given instant.</returns>
public override ZoneInterval GetZoneInterval(Instant instant)
{
if (tailZone != null && instant >= tailZoneStart)
{
// Clamp the tail zone interval to start at the end of our final period, if necessary, so that the
// join is seamless.
ZoneInterval intervalFromTailZone = tailZone.GetZoneInterval(instant);
return(intervalFromTailZone.Start < tailZoneStart ? firstTailZoneInterval : intervalFromTailZone);
}
// Special case to avoid the later logic being problematic
if (instant == Instant.MaxValue)
{
return(periods[periods.Length - 1]);
}
int lower = 0; // Inclusive
int upper = periods.Length; // Exclusive
while (lower < upper)
{
int current = (lower + upper) / 2;
var candidate = periods[current];
if (candidate.Start > instant)
{
upper = current;
}
else if (candidate.End <= instant)
{
lower = current + 1;
}
else
{
return(candidate);
}
}
// Note: this would indicate a bug. The time zone is meant to cover the whole of time.
throw new InvalidOperationException(string.Format("Instant {0} did not exist in time zone {1}", instant, Id));
}
/// <summary>
/// Reads a time zone from the specified reader.
/// </summary>
/// <param name="reader">The reader.</param>
/// <param name="id">The id.</param>
/// <returns>The time zone.</returns>
internal static DateTimeZone Read([Trusted][NotNull] IDateTimeZoneReader reader, [Trusted][NotNull] string id)
{
Preconditions.DebugCheckNotNull(reader, nameof(reader));
Preconditions.DebugCheckNotNull(id, nameof(id));
int size = reader.ReadCount();
var periods = new ZoneInterval[size];
// It's not entirely clear why we don't just assume that the first zone interval always starts at Instant.BeforeMinValue
// (given that we check that later) but we don't... and changing that now could cause compatibility issues.
var start = reader.ReadZoneIntervalTransition(null);
for (int i = 0; i < size; i++)
{
var name = reader.ReadString();
var offset = reader.ReadOffset();
var savings = reader.ReadOffset();
var nextStart = reader.ReadZoneIntervalTransition(start);
periods[i] = new ZoneInterval(name, start, nextStart, offset, savings);
start = nextStart;
}
var tailZone = reader.ReadByte() == 1 ? DaylightSavingsDateTimeZone.Read(reader, id + "-tail") : null;
return(new PrecalculatedDateTimeZone(id, periods, tailZone));
}
internal static ZoneIntervalPair Ambiguous(ZoneInterval early, ZoneInterval late)
{
return(new ZoneIntervalPair(early, late, 2));
}
// Visible for tests
internal BclAdjustmentRule(ZoneInterval zoneInterval)
{
StandardOffset = zoneInterval.StandardOffset;
Savings = zoneInterval.Savings;
PartialMap = PartialZoneIntervalMap.ForZoneInterval(zoneInterval);
}
internal static BclAdjustmentRule ConvertUnixRuleToBclAdjustmentRule(TimeZoneInfo.AdjustmentRule rule,
string standardName, string daylightName, TimeSpan zoneStandardOffset, TimeSpan ruleStandardOffset,
bool forceDaylightSavings)
{
// On .NET Core on Unix, each "adjustment rule" is effectively just a zone interval. The transitions are only used
// to give the time of day values to combine with rule.DateStart and rule.DateEnd. It's all a bit odd.
// The *last* adjustment rule internally can work like a normal Windows standard/daylight rule, but that's only
// exposed in .NET 6.0, and those rules are handled in FromUnixAdjustmentRule.
// (Currently we don't have a way of handling a fixed-date rule to the end of time that really represents alternating
// standard/daylight. Apparently that's not an issue.)
// The start of each rule is indicated by the start date with the time-of-day of the transition, interpreted as being in the *zone* standard offset
// (rather than the *rule* standard offset). Some rules effectively start in daylight time, but only when there are consecutive daylight time
// rules. This is handled in FixOverlappingUnixRules.
var bclLocalStart = rule.DateStart + rule.DaylightTransitionStart.TimeOfDay.TimeOfDay;
var bclUtcStart = DateTime.SpecifyKind(bclLocalStart == DateTime.MinValue ? DateTime.MinValue : bclLocalStart - zoneStandardOffset, DateTimeKind.Utc);
var bclSavings = rule.DaylightDelta;
// The end of each rule is indicated by the start date with the time-of-day of the transition, interpreted as being in the *zone* standard offset
// with the *rule* daylight delta.
var bclLocalEnd = rule.DateEnd + rule.DaylightTransitionEnd.TimeOfDay.TimeOfDay;
var bclUtcEnd = DateTime.SpecifyKind(rule.DateEnd == MaxDate ? DateTime.MaxValue : bclLocalEnd - (zoneStandardOffset + bclSavings), DateTimeKind.Utc);
// For just a couple of time zones in .NET 6, there are adjustment rules which appear to be invalid
// in the normal expectation of "starts in standard, ends in daylight".
// Example in America/Creston: 1944-01-01 - 1944-01-01: Daylight delta: +01; DST starts January 01 at 00:00:00 and ends January 01 at 00:00:59.999
// Handle this by treating the rule as starting in daylight time.
if (bclUtcStart >= bclUtcEnd)
{
bclUtcStart -= bclSavings;
}
// If the zone says that the start of the rule is in DST, but the rule has no daylight savings,
// assume we actually want an hour of DST but one less hour of standard offset.
// See Europe/Dublin in 1960 for example, in .NET 6:
// 1960-04-10 - 1960-10-02: Daylight delta: +00; DST starts April 10 at 03:00:00 and ends October 02 at 02:59:59.999 (force daylight)
if (forceDaylightSavings)
{
bclSavings = TimeSpan.FromHours(1);
ruleStandardOffset -= bclSavings;
}
// Handle changes crossing the international date line, which used to be represented as savings of +/-23
// hours (but could conceivably be more).
// Note: I can't currently reproduce this in .NET Core 3.1 or .NET 6. It may be a legacy Mono artifact;
// it does no harm to preserve it, however.
if (bclSavings.Hours < -14)
{
bclSavings += TimeSpan.FromDays(1);
}
else if (bclSavings.Hours > 14)
{
bclSavings -= TimeSpan.FromDays(1);
}
// Now all the values are sensible - and in particular, now the daylight savings are in a range that can be represented by
// Offset - we can converted everything to Noda Time types.
var nodaStart = bclUtcStart == DateTime.MinValue ? Instant.BeforeMinValue : bclUtcStart.ToInstant();
// The representation returned to us (not the internal representation) has an end point one second (before .NET 6)
// or one millisecond (.NET 6 onwards) before the transition. We round up to a properly exclusive end instant.
var endTimeCompensation = Duration.FromSeconds(1) - Duration.FromMilliseconds(bclLocalEnd.Millisecond);
var nodaEnd = bclUtcEnd == DateTime.MaxValue ? Instant.AfterMaxValue : bclUtcEnd.ToInstant() + endTimeCompensation;
var nodaStandard = ruleStandardOffset.ToOffset();
var nodaSavings = bclSavings.ToOffset();
var nodaWallOffset = nodaStandard + nodaSavings;
var zoneInterval = new ZoneInterval(nodaSavings == Offset.Zero ? standardName : daylightName, nodaStart, nodaEnd, nodaWallOffset, nodaSavings);
return(new BclAdjustmentRule(zoneInterval));
}
private ZonedDateTime BuildZonedDateTime(ZoneInterval interval) => new ZonedDateTime(LocalDateTime.WithOffset(interval.WallOffset), Zone);
/// <summary>
/// Initializes a new instance of the <see cref="HashCacheNode"/> class.
/// </summary>
/// <param name="interval">The zone interval.</param>
/// <param name="period"></param>
/// <param name="previous">The previous <see cref="HashCacheNode"/> node.</param>
private HashCacheNode(ZoneInterval interval, int period, HashCacheNode previous)
{
this.Period = period;
this.Interval = interval;
this.Previous = previous;
}
internal BclZoneIntervalMap(List <AdjustmentInterval> adjustmentIntervals, ZoneInterval headInterval, ZoneInterval tailInterval)
{
this.adjustmentIntervals = adjustmentIntervals;
this.headInterval = headInterval;
this.tailInterval = tailInterval;
}
internal FixedZoneIntervalMap(ZoneInterval interval)
{
this.interval = interval;
}
internal static ZoneIntervalPair Unambiguous(ZoneInterval interval)
{
return(new ZoneIntervalPair(interval, null, 1));
}
/// <summary>
/// Returns whether this zone interval has the same offsets and name as another.
/// </summary>
internal bool EqualIgnoreBounds([Trusted] ZoneInterval other)
{
Preconditions.DebugCheckNotNull(other, nameof(other));
return(other.WallOffset == WallOffset && other.Savings == Savings && other.Name == Name);
}
/// <summary>
/// Initializes a new instance of the <see cref="FixedDateTimeZone"/> class.
/// </summary>
/// <param name="id">The id.</param>
/// <param name="offset">The offset.</param>
public FixedDateTimeZone(string id, Offset offset) : base(id, true, offset, offset)
{
this.offset = offset;
interval = new ZoneInterval(id, Instant.MinValue, Instant.MaxValue, offset, Offset.Zero);
intervalPair = ZoneIntervalPair.Unambiguous(interval);
}
/// <summary> /// Builds a PartialZoneIntervalMap wrapping the given zone interval, taking its start and end as the start and end of /// the portion of the time line handled by the partial map. /// </summary> internal static PartialZoneIntervalMap ForZoneInterval(ZoneInterval interval) => new PartialZoneIntervalMap(interval.RawStart, interval.RawEnd, new SingleZoneIntervalMap(interval));
internal AdjustmentInterval(Instant start, DaylightSavingsDateTimeZone adjustmentZone, ZoneInterval seam)
{
this.start = start;
this.seam = seam;
this.adjustmentZone = adjustmentZone;
}
/// <summary>
/// Initializes a new instance of the <see cref="FixedDateTimeZone"/> class.
/// </summary>
/// <remarks>The name (for the <see cref="ZoneInterval"/>) is deemed to be the same as the ID.</remarks>
/// <param name="id">The id.</param>
/// <param name="offset">The offset.</param>
/// <param name="name">The name to use in the sole <see cref="ZoneInterval"/> in this zone.</param>
internal FixedDateTimeZone([NotNull] string id, Offset offset, [NotNull] string name) : base(id, true, offset, offset)
{
interval = new ZoneInterval(name, Instant.BeforeMinValue, Instant.AfterMaxValue, offset, Offset.Zero);
}
private ZonedDateTime BuildZonedDateTime(ZoneInterval interval)
{
return(new ZonedDateTime(localDateTime, interval.WallOffset, zone));
}
private ZoneIntervalPair(ZoneInterval early, ZoneInterval late, int matchingIntervals)
{
this.earlyInterval = early;
this.lateInterval = late;
this.matchingIntervals = matchingIntervals;
}
/// <summary>
/// Creates a new <see cref="BclDateTimeZone" /> from a <see cref="TimeZoneInfo"/> from the Base Class Library.
/// </summary>
/// <param name="bclZone">The original time zone to take information from.</param>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the given <c>TimeZoneInfo</c>.</returns>
public static BclDateTimeZone FromTimeZoneInfo([NotNull] TimeZoneInfo bclZone)
{
Preconditions.CheckNotNull(bclZone, "bclZone");
Offset standardOffset = Offset.FromTimeSpan(bclZone.BaseUtcOffset);
Offset minSavings = Offset.Zero; // Just in case we have negative savings!
Offset maxSavings = Offset.Zero;
var rules = bclZone.GetAdjustmentRules();
if (!bclZone.SupportsDaylightSavingTime || rules.Length == 0)
{
var fixedInterval = new ZoneInterval(bclZone.StandardName, Instant.MinValue, Instant.MaxValue, standardOffset, Offset.Zero);
return(new BclDateTimeZone(bclZone, standardOffset, standardOffset, new FixedZoneIntervalMap(fixedInterval)));
}
var adjustmentIntervals = new List <AdjustmentInterval>();
var headInterval = ComputeHeadInterval(bclZone, rules[0]);
Instant previousEnd = headInterval != null ? headInterval.End : Instant.MinValue;
// TODO(Post-V1): Tidy this up. All of this is horrible.
for (int i = 0; i < rules.Length; i++)
{
var rule = rules[i];
ZoneRecurrence standard, daylight;
GetRecurrences(bclZone, rule, out standard, out daylight);
minSavings = Offset.Min(minSavings, daylight.Savings);
maxSavings = Offset.Max(maxSavings, daylight.Savings);
// Find the last valid transition by working back from the end of time. It's safe to unconditionally
// take the value here, as there must *be* some recurrences.
var lastStandard = standard.PreviousOrFail(LastValidTick, standardOffset, daylight.Savings);
var lastDaylight = daylight.PreviousOrFail(LastValidTick, standardOffset, Offset.Zero);
bool standardIsLater = lastStandard.Instant > lastDaylight.Instant;
Transition lastTransition = standardIsLater ? lastStandard : lastDaylight;
Offset seamSavings = lastTransition.NewOffset - standardOffset;
string seamName = standardIsLater ? bclZone.StandardName : bclZone.DaylightName;
Instant nextStart;
Instant ruleEnd = GetRuleEnd(rule, lastTransition);
// Handle the final rule, which may or may not to extend to the end of time. If it doesn't,
// we transition to standard time at the end of the rule.
if (i == rules.Length - 1)
{
// If the final transition was to standard time, we can just treat the seam as going on forever.
nextStart = standardIsLater ? Instant.MaxValue : ruleEnd;
var seam = new ZoneInterval(seamName, lastTransition.Instant, nextStart, lastTransition.NewOffset, seamSavings);
var adjustmentZone = new DaylightSavingsDateTimeZone("ignored", standardOffset, standard.ToInfinity(), daylight.ToInfinity());
adjustmentIntervals.Add(new AdjustmentInterval(previousEnd, adjustmentZone, seam));
previousEnd = nextStart;
}
else
{
// Handle one rule going into another. This is the cause of much pain, as there are several options:
// 1) Going into a "normal" rule with two transitions per year.
// 2) Going into a "single transition" rule, signified by a transition "into" the current offset
// right at the start of the year. This is treated as if the on-the-edge transition doesn't exist.
//
// Additionally, there's the possibility that the offset at the start of the next rule (i.e. the
// one before the first transition) isn't the same as the offset at the end of end of the current rule
// (i.e. lastTransition.NewOffset). This only occurs for Namibia time as far as we've seen, but in that
// case we create a seam which only goes until the end of this rule, then an extra zone interval for
// the time between the start of the rule and the first transition, then we're as normal, starting at
// the first transition. See bug 115 for a bit more information.
var nextRule = rules[i + 1];
ZoneRecurrence nextStandard, nextDaylight;
GetRecurrences(bclZone, nextRule, out nextStandard, out nextDaylight);
// By using the seam's savings for *both* checks, we can detect "daylight to daylight" and
// "standard to standard" transitions as happening at the very start of the rule.
var firstStandard = nextStandard.NextOrFail(lastTransition.Instant, standardOffset, seamSavings);
var firstDaylight = nextDaylight.NextOrFail(lastTransition.Instant, standardOffset, seamSavings);
// Ignore any "right at the start of the rule" transitions.
var firstStandardInstant = firstStandard.Instant == ruleEnd ? Instant.MaxValue : firstStandard.Instant;
var firstDaylightInstant = firstDaylight.Instant == ruleEnd ? Instant.MaxValue : firstDaylight.Instant;
bool firstStandardIsEarlier = firstStandardInstant < firstDaylightInstant;
var firstTransition = firstStandardIsEarlier ? firstStandard : firstDaylight;
nextStart = firstTransition.Instant;
var seamEnd = nextStart;
AdjustmentInterval startOfRuleExtraSeam = null;
Offset previousOffset = firstStandardIsEarlier ? firstDaylight.NewOffset : firstStandard.NewOffset;
if (previousOffset != lastTransition.NewOffset)
{
seamEnd = ruleEnd;
// Recalculate the *real* transition, as we're now going from a different wall offset...
var firstRule = firstStandardIsEarlier ? nextStandard : nextDaylight;
nextStart = firstRule.NextOrFail(ruleEnd, standardOffset, previousOffset - standardOffset).Instant;
var extraSeam = new ZoneInterval(firstStandardIsEarlier ? bclZone.DaylightName : bclZone.StandardName,
ruleEnd, nextStart, previousOffset, previousOffset - standardOffset);
// The extra adjustment interval is really just a single zone interval; we'll never need the DaylightSavingsDateTimeZone part.
startOfRuleExtraSeam = new AdjustmentInterval(extraSeam.Start, null, extraSeam);
}
var seam = new ZoneInterval(seamName, lastTransition.Instant, seamEnd, lastTransition.NewOffset, seamSavings);
var adjustmentZone = new DaylightSavingsDateTimeZone("ignored", standardOffset, standard.ToInfinity(), daylight.ToInfinity());
adjustmentIntervals.Add(new AdjustmentInterval(previousEnd, adjustmentZone, seam));
if (startOfRuleExtraSeam != null)
{
adjustmentIntervals.Add(startOfRuleExtraSeam);
}
previousEnd = nextStart;
}
}
ZoneInterval tailInterval = previousEnd == Instant.MaxValue ? null
: new ZoneInterval(bclZone.StandardName, previousEnd, Instant.MaxValue, standardOffset, Offset.Zero);
IZoneIntervalMap uncachedMap = new BclZoneIntervalMap(adjustmentIntervals, headInterval, tailInterval);
IZoneIntervalMap cachedMap = CachingZoneIntervalMap.CacheMap(uncachedMap, CachingZoneIntervalMap.CacheType.Hashtable);
return(new BclDateTimeZone(bclZone, standardOffset + minSavings, standardOffset + maxSavings, cachedMap));
}
