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Merged
mosuem merged 3 commits into from
Dec 25, 2025
Merged

Tweaks and anti-bug-ensurence. #231

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e103d04
Tweaks and anti-bug-ensurence.
lrhn Dec 18, 2025
a01601e
Rebase
mosuem Dec 25, 2025
65a8dde
fix typo
mosuem Dec 25, 2025
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14,104 changes: 14,100 additions & 4 deletions lib/data/latest.dart
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3,689 changes: 3,685 additions & 4 deletions lib/data/latest_10y.dart
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24,765 changes: 24,761 additions & 4 deletions lib/data/latest_all.dart
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48 changes: 21 additions & 27 deletions lib/src/tzdata/zicfile.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@
// ignore_for_file: non_constant_identifier_names

import 'dart:collection';
import 'dart:convert' show ascii;
import 'dart:typed_data';

/// Time Zone information file magic header "TZif"
Expand Down Expand Up @@ -60,11 +59,7 @@ class _Header {

factory _Header.fromBytes(List<int> rawData) {
final data = rawData is Uint8List ? rawData : Uint8List.fromList(rawData);

final bdata = data.buffer.asByteData(
data.offsetInBytes,
data.lengthInBytes,
);
final bdata = ByteData.sublistView(data);

final tzh_ttisgmtcnt = bdata.getInt32(0);
final tzh_ttisstdcnt = bdata.getInt32(4);
Expand All @@ -84,16 +79,16 @@ class _Header {
}
}

/// Read NULL-terminated string
/// Read NUL-terminated string
String _readByteString(Uint8List data, int offset) {
for (var i = offset; i < data.length; i++) {
if (data[i] == 0) {
return ascii.decode(
data.buffer.asUint8List(data.offsetInBytes + offset, i - offset),
);
}
var i = offset;
for (; i < data.length; i++) {
final byte = data[i];
if (byte >= 1 && byte < 0x80) continue;
if (byte == 0) break;
throw FormatException('Not ASCII', data, i);
}
return ascii.decode(data.buffer.asUint8List(data.offsetInBytes + offset));
return String.fromCharCodes(data, offset, i);
}

/// This exception is thrown when Zone Info data is invalid.
Expand Down Expand Up @@ -171,10 +166,7 @@ class Location {
factory Location.fromBytes(String name, List<int> rawData) {
final data = rawData is Uint8List ? rawData : Uint8List.fromList(rawData);

final bdata = data.buffer.asByteData(
data.offsetInBytes,
data.lengthInBytes,
);
final bdata = ByteData.sublistView(data);

final magic1 = bdata.getUint32(0);
if (magic1 != _ziMagic) {
Expand All @@ -187,7 +179,7 @@ class Location {
switch (version1) {
case 0:
final header = _Header.fromBytes(
Uint8List.view(bdata.buffer, offset, _Header.size),
Uint8List.sublistView(bdata, offset, _Header.size),
);

// calculating data offsets
Expand Down Expand Up @@ -218,9 +210,10 @@ class Location {
}

// function to read from abbreviation buffer
final abbreviationsData = data.buffer.asUint8List(
data.offsetInBytes + abbreviationsOffset,
header.tzh_charcnt,
final abbreviationsData = Uint8List.sublistView(
data,
abbreviationsOffset,
abbreviationsOffset + header.tzh_charcnt,
);
final abbreviations = <String>[];
final abbreviationsCache = HashMap<int, int>();
Expand Down Expand Up @@ -298,7 +291,7 @@ class Location {
case 51:
// skip old version header/data
final header1 = _Header.fromBytes(
Uint8List.view(bdata.buffer, offset, _Header.size),
Uint8List.sublistView(bdata, offset, offset + _Header.size),
);
offset += _Header.size + header1.dataLength(4);

Expand All @@ -320,7 +313,7 @@ class Location {
offset += 20;

final header2 = _Header.fromBytes(
Uint8List.view(bdata.buffer, offset, _Header.size),
Uint8List.sublistView(bdata, offset, offset + _Header.size),
);

// calculating data offsets
Expand Down Expand Up @@ -351,9 +344,10 @@ class Location {
}

// function to read from abbreviation buffer
final abbreviationsData = data.buffer.asUint8List(
data.offsetInBytes + abbreviationsOffset,
header2.tzh_charcnt,
final abbreviationsData = Uint8List.sublistView(
data,
abbreviationsOffset,
abbreviationsOffset + header2.tzh_charcnt,
);
final abbreviations = <String>[];
final abbreviationsCache = HashMap<int, int>();
Expand Down
50 changes: 31 additions & 19 deletions lib/src/tzdb.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@
library;

import 'dart:collection';
import 'dart:convert' show ascii;
import 'dart:typed_data';
import 'location.dart';
import 'location_database.dart';
Expand All @@ -26,7 +25,7 @@ List<int> tzdbSerialize(LocationDatabase db) {
}

final r = Uint8List(bufferLength);
final rb = r.buffer.asByteData();
final rb = ByteData.sublistView(r);

var offset = 0;
for (final b in locationsInBytes) {
Expand All @@ -42,7 +41,7 @@ List<int> tzdbSerialize(LocationDatabase db) {
/// Deserialize TimeZone Database
Iterable<Location> tzdbDeserialize(List<int> rawData) sync* {
final data = rawData is Uint8List ? rawData : Uint8List.fromList(rawData);
final bdata = data.buffer.asByteData(data.offsetInBytes, data.lengthInBytes);
final bdata = ByteData.sublistView(data);

var offset = 0;
while (offset < data.length) {
Expand All @@ -52,7 +51,7 @@ Iterable<Location> tzdbDeserialize(List<int> rawData) sync* {
offset += 8;

yield _deserializeLocation(
data.buffer.asUint8List(data.offsetInBytes + offset, length),
Uint8List.sublistView(data, offset, offset + length),
);
offset += length;
}
Expand All @@ -78,10 +77,10 @@ Uint8List _serializeLocation(Location location) {
zoneAbbreviationOffsets.add(ai);
}

final List<int> encName = ascii.encode(location.name);
final name = location.name;

final nameOffset = 32;
final nameLength = encName.length;
final nameLength = name.length;
final abbreviationsOffset = nameOffset + nameLength;
final zonesOffset = _align(abbreviationsOffset + abbreviationsLength, 4);
final zonesLength = location.zones.length;
Expand All @@ -91,7 +90,7 @@ Uint8List _serializeLocation(Location location) {
final bufferLength = _align(transitionsOffset + transitionsLength * 9, 8);

final result = Uint8List(bufferLength);
final buffer = ByteData.view(result.buffer);
final buffer = ByteData.sublistView(result);

// write header
buffer.setUint32(0, nameOffset);
Expand All @@ -104,9 +103,13 @@ Uint8List _serializeLocation(Location location) {
buffer.setUint32(28, transitionsLength);

// write name
offset = nameOffset;
for (final c in encName) {
buffer.setUint8(offset++, c);
for (var i = 0; i < name.length; i++) {
final char = name.codeUnitAt(i);
if (char <= 0x7f) {
buffer.setUint8(nameOffset + i, char);
} else {
throw FormatException('Not ASCII', name, i);
}
}

// Write abbreviations.
Expand Down Expand Up @@ -145,7 +148,7 @@ Uint8List _serializeLocation(Location location) {
}

Location _deserializeLocation(Uint8List data) {
final bdata = data.buffer.asByteData(data.offsetInBytes, data.lengthInBytes);
final bdata = ByteData.sublistView(data);
var offset = 0;

// Header
Expand All @@ -169,9 +172,8 @@ Location _deserializeLocation(Uint8List data) {
final transitionsOffset = bdata.getUint32(24);
final transitionsLength = bdata.getUint32(28);

final name = ascii.decode(
data.buffer.asUint8List(data.offsetInBytes + nameOffset, nameLength),
);
assert(_allAscii(data, nameOffset, nameOffset + nameLength));
final name = String.fromCharCodes(data, nameOffset, nameOffset + nameLength);
final abbreviations = <String>[];
final zones = <TimeZone>[];
final transitionAt = <int>[];
Expand All @@ -184,9 +186,8 @@ Location _deserializeLocation(Uint8List data) {
final abbreviationsEnd = abbreviationsOffset + abbreviationsLength;
for (var i = abbreviationsOffset; i < abbreviationsEnd; i++) {
if (data[i] == 0) {
final abbreviation = ascii.decode(
data.buffer.asUint8List(data.offsetInBytes + offset, i - offset),
);
assert(_allAscii(data, offset, i));
final abbreviation = String.fromCharCodes(data, offset, i);
abbreviations.add(abbreviation);
offset = i + 1;
}
Expand Down Expand Up @@ -236,6 +237,17 @@ Location _deserializeLocation(Uint8List data) {
}

int _align(int offset, int boundary) {
final i = offset % boundary;
return i == 0 ? offset : offset + (boundary - i);
assert(boundary > 1 && _isPowerOf2(boundary));
final mask = boundary - 1;
return (offset + mask) & ~mask;
}

bool _isPowerOf2(int value) => value > 0 && (value & (value - 1)) == 0;

bool _allAscii(Uint8List bytes, int start, int end) {
var bits = 0;
for (var i = start; i < end; i++) {
bits |= bytes[i];
}
return bits <= 0x7f;
}
43 changes: 31 additions & 12 deletions tool/encode_dart.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -9,21 +9,41 @@ Future<void> main(List<String> args) async {
final bytes = File(tzDataPath).readAsBytesSync();
final generatedDartFile = generateDartFile(
name: p.basenameWithoutExtension(tzDataPath),
data: bytesAsString(bytes),
data: bytes,
);
File(dartLibraryPath).writeAsStringSync(generatedDartFile);
}

String bytesAsString(Uint8List bytes) {
assert(bytes.length.isEven);
return bytes.buffer
.asUint16List()
.map((u) => '\\u${u.toRadixString(16).padLeft(4, '0')}')
.join();
String bytesAsString(
Uint8List bytes, {
String prefix = '',
String indent = '',
}) {
final buffer = StringBuffer();
buffer.write('\'');
var column = prefix.length + 1;
for (var index = 0; index < bytes.length; index++) {
final byte = bytes[index];
if (column > 74) {
// Not space for one encoding + "';".
buffer
..write('\'\n')
..write(indent)
..write('\'');
column = indent.length + 1;
}
buffer
..write(byte < 16 ? r'\x0' : r'\x')
..write(byte.toRadixString(16));
column += 4;
}
buffer.write('\'');
return buffer.toString();
}

String generateDartFile({required String name, required String data}) =>
'''// This is a generated file. Do not edit.
String generateDartFile({required String name, required Uint8List data}) =>
'''
// This is a generated file. Do not edit.
import 'dart:typed_data';

import '../src/env.dart';
Expand All @@ -35,14 +55,13 @@ import '../src/exceptions.dart';
void initializeTimeZones() {
try {
initializeDatabase(
Uint16List.fromList(_embeddedData.codeUnits).buffer.asUint8List());
Uint8List.fromList(_embeddedData.codeUnits));
}
// ignore: avoid_catches_without_on_clauses
catch (e) {
throw TimeZoneInitException(e.toString());
}
}

const _embeddedData =
'$data';
const _embeddedData = ${bytesAsString(data, prefix: 'const _embeddedData = ', indent: ' ')};
''';