Make Location.offset a Duration

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 0.11.0
+
+- Make `Location.offset` a `Duration` instead of an `int`.
+
 # 0.10.2
 
 - Upgrade minimum SDK to `^3.10.0` and the databases to [2025c].

lib/src/date_time.dart

@@ -22,12 +22,12 @@ class TZDateTime implements DateTime {
     // Get the offset at local (first estimate).
     final localInstant = local.millisecondsSinceEpoch;
     final localTimezone = location.lookupTimeZone(localInstant);
-    final localOffset = localTimezone.timeZone.offset;
+    final localOffset = localTimezone.timeZone.offset.inMilliseconds;
 
     // Adjust localInstant using the estimate and recalculate the offset.
     final adjustedInstant = localInstant - localOffset;
     final adjustedTimezone = location.lookupTimeZone(adjustedInstant);
-    final adjustedOffset = adjustedTimezone.timeZone.offset;
+    final adjustedOffset = adjustedTimezone.timeZone.offset.inMilliseconds;
 
     var milliseconds = localInstant - adjustedOffset;
 
@@ -42,7 +42,8 @@ class TZDateTime implements DateTime {
               location
                   .lookupTimeZone(localInstant - adjustedOffset)
                   .timeZone
-                  .offset) {
+                  .offset
+                  .inMilliseconds) {
         milliseconds = adjustedInstant;
       }
     }
@@ -269,9 +270,7 @@ class TZDateTime implements DateTime {
       );
 
   TZDateTime._(this.native, this.location, this.timeZone)
-    : _localDateTime = _isUtc(location)
-          ? native
-          : native.add(_timeZoneOffset(timeZone));
+    : _localDateTime = _isUtc(location) ? native : native.add(timeZone.offset);
 
   /// Constructs a new [TZDateTime] instance based on [formattedString].
   ///
@@ -362,7 +361,7 @@ class TZDateTime implements DateTime {
   String toIso8601String() => _toString(iso8601: true);
 
   String _toString({bool iso8601 = true}) {
-    var offset = timeZone.offset;
+    final offset = timeZone.offset;
 
     final y = _fourDigits(year);
     final m = _twoDigits(month);
@@ -377,10 +376,10 @@ class TZDateTime implements DateTime {
     if (isUtc) {
       return '$y-$m-$d$sep$h:$min:$sec.$ms${us}Z';
     } else {
-      final offSign = offset.sign >= 0 ? '+' : '-';
-      offset = offset.abs() ~/ 1000;
-      final offH = _twoDigits(offset ~/ 3600);
-      final offM = _twoDigits((offset % 3600) ~/ 60);
+      final offSign = offset.isNegative ? '-' : '+';
+      final offsetSeconds = offset.abs().inSeconds;
+      final offH = _twoDigits(offsetSeconds ~/ 3600);
+      final offM = _twoDigits((offsetSeconds % 3600) ~/ 60);
 
       return '$y-$m-$d$sep$h:$min:$sec.$ms$us$offSign$offH$offM';
     }
@@ -490,10 +489,7 @@ class TZDateTime implements DateTime {
   /// local time. Java, C# and Ruby return the difference between local time and
   /// UTC.
   @override
-  Duration get timeZoneOffset => _timeZoneOffset(timeZone);
-
-  static Duration _timeZoneOffset(TimeZone timeZone) =>
-      Duration(milliseconds: timeZone.offset);
+  Duration get timeZoneOffset => timeZone.offset;
 
   /// The year.
   @override

lib/src/location.dart

@@ -71,7 +71,8 @@ class Location {
   /// translate instant in time expressed as milliseconds since
   /// January 1, 1970 00:00:00 UTC to this [Location].
   int translate(int millisecondsSinceEpoch) {
-    return millisecondsSinceEpoch + timeZone(millisecondsSinceEpoch).offset;
+    return millisecondsSinceEpoch +
+        timeZone(millisecondsSinceEpoch).offset.inMilliseconds;
   }
 
   /// translate instant in time expressed as milliseconds since
@@ -84,14 +85,18 @@ class Location {
 
     var utc = millisecondsSinceEpoch;
 
-    if (tz.offset != 0) {
-      utc -= tz.offset;
+    final offset = tz.offset.inMilliseconds;
+    if (offset != 0) {
+      utc -= offset;
 
       if (utc < start) {
         utc =
-            millisecondsSinceEpoch - lookupTimeZone(start - 1).timeZone.offset;
+            millisecondsSinceEpoch -
+            lookupTimeZone(start - 1).timeZone.offset.inMilliseconds;
       } else if (utc >= end) {
-        utc = millisecondsSinceEpoch - lookupTimeZone(end).timeZone.offset;
+        utc =
+            millisecondsSinceEpoch -
+            lookupTimeZone(end).timeZone.offset.inMilliseconds;
       }
     }
 
@@ -151,8 +156,9 @@ class Location {
     final start = t.start;
     final end = t.end;
 
-    if (tz.offset != 0) {
-      final utc = millisecondsSinceEpoch - tz.offset;
+    final offset = tz.offset.inMilliseconds;
+    if (offset != 0) {
+      final utc = millisecondsSinceEpoch - offset;
 
       if (utc < start) {
         tz = lookupTimeZone(start - 1).timeZone;
@@ -242,10 +248,14 @@ class Location {
 /// A [TimeZone] represents a single time zone such as CEST or CET.
 class TimeZone {
   // ignore: constant_identifier_names
-  static const TimeZone UTC = TimeZone(0, isDst: false, abbreviation: 'UTC');
+  static const TimeZone UTC = TimeZone(
+    Duration.zero,
+    isDst: false,
+    abbreviation: 'UTC',
+  );
 
   /// Milliseconds east of UTC.
-  final int offset;
+  final Duration offset;
 
   /// Is this [TimeZone] Daylight Savings Time?
   final bool isDst;

lib/src/tools.dart

@@ -533,7 +533,7 @@ Location tzfileLocationToNativeLocation(tzfile.Location loc) {
   for (final z in loc.zones) {
     zones.add(
       TimeZone(
-        z.offset * 1000,
+        Duration(seconds: z.offset),
         isDst: z.isDst,
         abbreviation: loc.abbreviations[z.abbreviationIndex],
       ),

lib/src/tzdb.dart

@@ -122,7 +122,7 @@ Uint8List _serializeLocation(Location location) {
   offset = zonesOffset;
   for (var i = 0; i < location.zones.length; i++) {
     final zone = location.zones[i];
-    buffer.setInt32(offset, zone.offset ~/ 1000); // convert to sec
+    buffer.setInt32(offset, zone.offset.inSeconds); // convert to sec
     buffer.setUint8(offset + 4, zone.isDst ? 1 : 0);
     buffer.setUint8(offset + 5, zoneAbbreviationOffsets[i]);
     offset += 8;
@@ -203,7 +203,7 @@ Location _deserializeLocation(Uint8List data) {
   offset = zonesOffset;
   assert((offset % 4) == 0);
   for (var i = 0; i < zonesLength; i++) {
-    final zoneOffset = bdata.getInt32(offset) * 1000; // convert to ms
+    final zoneOffset = Duration(seconds: bdata.getInt32(offset));
     final zoneIsDst = bdata.getUint8(offset + 4);
     final zoneAbbreviationIndex = bdata.getUint8(offset + 5);
     offset += 8;

pubspec.yaml

@@ -1,7 +1,7 @@
 name: timezone
 description: Time zone databases and time zone aware `DateTime`.
 repository: https://github.com/srawlins/timezone
-version: 0.10.2
+version: 0.11.0
 
 environment:
   sdk: ^3.10.0