updated to null-safety

Author: mars3142

.github/workflows/testing.yml

@@ -35,7 +35,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - uses: axel-op/dart-package-analyzer/with-full-sdk@stable
+      - uses: axel-op/dart-package-analyzer@v3
         id: analysis # set an id for the current step
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.2.0
+
+- package is now null-safety
+
 ## 0.1.2+2
 
 - remove dart:io - more web compatibility

analysis_options.yaml

@@ -3,6 +3,7 @@ include: package:effective_dart/analysis_options.yaml
 linter:
   rules:
     lines_longer_than_80_chars: false
+    avoid_equals_and_hash_code_on_mutable_classes: false
 
 analyzer:
   exclude:

example/main.dart

@@ -3,10 +3,10 @@ import 'dart:io';
 
 import 'package:freewig/freewig.dart';
 
-Future<Cartridge> parseFile(File file) async {
+Future<Cartridge?> parseFile(File file) async {
   final bytes = await file.readAsBytes();
   final completer = Completer<Cartridge>();
-  await Future<Cartridge>(() => parseData(bytes))
+  await Future<Cartridge?>(() => parseData(bytes))
       .then(completer.complete)
       .catchError(completer.completeError);
   return completer.future;
@@ -16,34 +16,42 @@ void main(List<String> arguments) async {
   var file = File(arguments[0]); // path/incl/cartridge.gwc
   var cartridge = await parseFile(file);
 
-  var export = Directory('export');
-  var exists = await export.exists();
-  if (exists) {
-    await export.delete(recursive: true);
-  }
-  await export.create(recursive: true);
+  if (cartridge != null) {
+    var export = Directory('export');
+    var exists = await export.exists();
+    if (exists) {
+      await export.delete(recursive: true);
+    }
+    await export.create(recursive: true);
 
-  var contents = '';
-  contents += 'Cartridge-Id: ${cartridge.cartridgeGuid}\n';
-  contents += 'Name: ${cartridge.cartridgeName}\n';
-  contents += 'Description: ${cartridge.cartridgeDesc}\n';
-  contents += 'StartLocation: ${cartridge.startLocationDesc}\n';
-  contents += 'Latitude: ${cartridge.latLng.latitude}\n';
-  contents += 'Longitude: ${cartridge.latLng.longitude}\n';
-  contents += 'Player: ${cartridge.playerName}\n';
-  contents += 'Author: ${cartridge.author}\n';
-  contents += 'Type: ${cartridge.typeOfCartridge}\n';
-  contents += 'Device: ${cartridge.recommendDevice}\n';
-  contents += 'Version: ${cartridge.version}\n';
-  contents += '\n';
-  contents += 'Completion-Code: ${cartridge.completionCode}\n';
-  contents += '\n';
-  contents += 'ItemCount: ${cartridge.mediaObjects.length}\n';
-  var infoFile = File('${export.path}/cartridge_info.txt');
-  await infoFile.writeAsString(contents);
+    var contents = '';
+    contents += 'Cartridge-Id: ${cartridge.cartridgeGuid}\n';
+    contents += 'Name: ${cartridge.cartridgeName}\n';
+    contents += 'Description: ${cartridge.cartridgeDesc}\n';
+    contents += 'StartLocation: ${cartridge.startLocationDesc}\n';
+    contents += 'Latitude: ${cartridge.latLng.latitude}\n';
+    contents += 'Longitude: ${cartridge.latLng.longitude}\n';
+    contents += 'Player: ${cartridge.playerName}\n';
+    contents += 'Author: ${cartridge.author}\n';
+    contents += 'Type: ${cartridge.typeOfCartridge}\n';
+    contents += 'Device: ${cartridge.recommendDevice}\n';
+    contents += 'Version: ${cartridge.version}\n';
+    contents += '\n';
+    contents += 'Completion-Code: ${cartridge.completionCode}\n';
+    contents += '\n';
+    contents += 'ItemCount: ${cartridge.mediaCount}\n';
+    var infoFile = File('${export.path}/cartridge_info.txt');
+    await infoFile.writeAsString(contents);
 
-  cartridge.mediaObjects.forEach((index, data) async {
-    var objectFile = File('${export.path}/object_$index.${data.objectType}');
-    await objectFile.writeAsBytes(data.data);
-  });
+    for (var index = 0; index < cartridge.mediaCount; index++) {
+      final data = cartridge.getMedia(index);
+      if (data != null) {
+        var objectFile =
+            File('${export.path}/object_$index.${data.objectType}');
+        await objectFile.writeAsBytes(data.data);
+      }
+    }
+  } else {
+    print("The cartridge is invalid");
+  }
 }

lib/src/binary_reader.dart

@@ -23,7 +23,7 @@ class BinaryReader {
 
   /// Initialise the [BinaryReader] with data and endian, so the reader knows how to
   /// interpret the bytes.
-  BinaryReader({ByteData byteData, Endian endian})
+  BinaryReader({required ByteData byteData, Endian endian = Endian.little})
       : _byteData = byteData,
         _endian = endian,
         _index = 0;

lib/src/latlng.dart

@@ -32,11 +32,20 @@ class LatLng {
     return _format(_longitude, 'EW');
   }
 
+  @override
+  String toString() {
+    return "$latitude $longitude".trim();
+  }
+
   String _format(double value, String suffix) {
     final isNegative = value < 0;
     value = value.abs();
 
     final degrees = value.floor();
+    if (degrees == 360) {
+      return "";
+    }
+
     final minutes = (value - degrees) * 60.0;
 
     var result = '';

lib/src/models/cartridge.dart

@@ -12,14 +12,11 @@
  * all copies or substantial portions of the Software.
  */
 
-import 'package:meta/meta.dart';
-
 import '../../freewig.dart';
 import '../binary_reader.dart';
 import 'media.dart';
 
 /// A [Cartridge] represents the GWC file
-@immutable
 class Cartridge {
   /// The altitude of the start coordinate
   final double altitude;
@@ -60,16 +57,20 @@ class Cartridge {
   /// Completion code (can be encrypted with lua)
   final String completionCode;
 
-  /// Map of all [Media] objects
-  final Map<int, Media> mediaObjects;
-
   final int _splashScreenId;
 
   final int _smallIconId;
 
+  final BinaryReader _source;
+
+  final Map<int, int> _references;
+
+  var _lastObject = -1;
+
+  Media? _lastMedia;
+
   Cartridge._(
     this.cartridgeGuid,
-    this.mediaObjects,
     this.altitude,
     this.author,
     this.cartridgeDesc,
@@ -84,11 +85,13 @@ class Cartridge {
     this.startLocationDesc,
     this.typeOfCartridge,
     this.version,
+    this._references,
+    this._source,
   );
 
   /// Reading the GWC file and create a [Cartridge] or null in case of any
   /// parsing error.
-  factory Cartridge(BinaryReader reader) {
+  static Cartridge? create(BinaryReader reader) {
     try {
       final count = reader.getUShort();
       final references = <int, int>{};
@@ -129,14 +132,8 @@ class Cartridge {
 
       final completionCode = reader.getASCIIZ();
 
-      // initialise objects after cartridge data is loaded
-      final objects = <int, Media>{};
-      references.forEach((index, address) =>
-          {objects.putIfAbsent(index, () => Media(reader, index, address))});
-
       return Cartridge._(
         cartridgeGuid,
-        objects,
         altitude,
         author,
         cartridgeDesc,
@@ -154,6 +151,8 @@ class Cartridge {
         startLocationDesc,
         typeOfCartridge,
         version,
+        references,
+        reader,
       );
     } on Exception catch (ex) {
       print('Exception: $ex');
@@ -166,22 +165,42 @@ class Cartridge {
       identical(this, other) ||
       other is Cartridge &&
           runtimeType == other.runtimeType &&
-          cartridgeGuid == other.cartridgeGuid &&
-          mediaObjects == other.mediaObjects;
+          cartridgeGuid == other.cartridgeGuid;
 
   @override
-  int get hashCode => cartridgeGuid.hashCode ^ mediaObjects.hashCode;
+  int get hashCode => cartridgeGuid.hashCode;
+
+  /// get Media with objectId or null, if not available
+  Media? getMedia(int objectId) {
+    if (_lastObject == objectId && _lastMedia != null) {
+      return _lastMedia!;
+    }
+
+    if (_references.containsKey(objectId)) {
+      final address = _references[objectId];
+      final media = Media.create(_source, objectId, address!);
+
+      if (media != null) {
+        if (media.data.length < 128000) {
+          _lastObject = objectId;
+          _lastMedia = media;
+        }
+
+        return media;
+      }
+    }
+    return null;
+  }
+
+  /// get the count of attached media
+  int get mediaCount => _references.length;
 
   /// get splash screen media or null if not available
-  Media get splashScreen => mediaObjects.containsKey(_splashScreenId)
-      ? mediaObjects[_splashScreenId]
-      : null;
+  Media? get splashScreen => getMedia(_splashScreenId);
 
   /// get small icon media or null if not available
-  Media get smallIcon => mediaObjects.containsKey(_smallIconId)
-      ? mediaObjects[_smallIconId]
-      : null;
+  Media? get smallIcon => getMedia(_smallIconId);
 
   /// get luac media or null if not available
-  Media get luac => mediaObjects.containsKey(0) ? mediaObjects[0] : null;
+  Media? get luac => getMedia(0);
 }

lib/src/models/media.dart

@@ -34,10 +34,10 @@ class Media {
   ///
   /// It starts at address (from [SeekOrigin.begin]) and uses the data for
   /// interpret the data as media. If it can be read, the return will be a
-  /// [Media] object. In case of an exception the result will be null.
-  factory Media(BinaryReader reader, int objectId, int address) {
+  /// [Media] object. In case of an exception or empty data the result will be null.
+  static Media? create(BinaryReader reader, int objectId, int address) {
     try {
-      Uint8List data;
+      Uint8List? data;
       var objectType = 0;
       reader.seek(address, SeekOrigin.begin);
       if (objectId == 0) {
@@ -48,8 +48,11 @@ class Media {
           data = _readMediaData(reader);
         }
       }
-      final object = Media._(_getObjectType(objectType), data);
-      return object;
+      if (data != null) {
+        final object = Media._(_getObjectType(objectType), data);
+        return object;
+      }
+      return null;
     } on Exception catch (ex) {
       print('Exception: $ex');
       return null;

lib/src/parser.dart

@@ -20,7 +20,7 @@ import 'models/cartridge.dart';
 /// Parses a byte list and create a [Cartridge]
 ///
 /// If the byte list is a valid GWC file, the result will be [Cartridge] or null, if the parser failed.
-Cartridge parseData(Uint8List bytes) {
+Cartridge? parseData(Uint8List bytes) {
   try {
     const header = {0x02, 0x0a, 0x43, 0x41, 0x52, 0x54, 0x00}; // magic header
     final reader = BinaryReader(
@@ -34,7 +34,7 @@ Cartridge parseData(Uint8List bytes) {
       }
     }
 
-    return Cartridge(reader);
+    return Cartridge.create(reader);
   } on Exception catch (_) {
     return null;
   }

pubspec.yaml

@@ -1,11 +1,11 @@
 name: freewig
-version: 0.1.2+2
+version: 0.2.0
 description: >
   Freewig can be used to extract the meta data and media files from Wherigo Cartridges
 homepage: https://github.com/mars3142/freewig
 
 environment:
-  sdk: '>=2.7.0 <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   meta: ^1.1.8