Add support for dynamic chunk size.

Add interface to get the downloaded underlying data.
Add interface to force close the http data.

lib/us/vid_us_data_http_reader.dart

@@ -1,3 +1,4 @@
+import 'dart:math';
 import 'dart:typed_data';
 import 'package:dio/dio.dart';
 
@@ -13,7 +14,7 @@ class DownloadErrorException implements Exception {
   DownloadErrorException(this._message);
 }
 
-typedef DownloadCallback = void Function(double progress);
+typedef DownloadCallback = void Function(double progress, DownloadErrorException? error);
 
 class VidUsDataHttpReader {
   late Uint8List _underlyingData = Uint8List(0);
@@ -22,13 +23,14 @@ class VidUsDataHttpReader {
   late bool _error;
   late String _errorMsg;
   late String _url;
-  late int _chunkSize;
+  late int _minChunkSize;
   late Dio _dio;
+  late double _downloadProgress = 0;
 
   DownloadCallback? downloadCallback;
 
-  VidUsDataHttpReader(String url, {this.downloadCallback, int chunkSize = 65536, int connectTimeout = 30000, int receiveTimeout = 30000}) {
-    _chunkSize = chunkSize;
+  VidUsDataHttpReader(String url, {this.downloadCallback, int minChunkSize = 65536, int connectTimeout = 30000, int receiveTimeout = 30000}) {
+    _minChunkSize = minChunkSize;
     _url = url;
     _error = false;
     _errorMsg = '';
@@ -39,47 +41,65 @@ class VidUsDataHttpReader {
     _startDownload();
   }
 
+  ///Return the internal underlying data.
+  Uint8List toBytes() {
+    return _underlyingData;
+  }
+
+  ///Start the download in async way.
   void _startDownload() async {
     try {
       //get file info
       var fileSize = await _getFileSize();
       if (!_error) {
         _underlyingData = Uint8List(fileSize);
-        if (fileSize < _chunkSize) {
-          await _downloadChunk(0, fileSize -1);
+        if (fileSize < _minChunkSize) {
+          await _downloadChunk(0, fileSize - 1);
           if (!_error && downloadCallback != null) {
-            var progress = _bufferSize / fileSize;
-            downloadCallback!(progress);
+            _downloadProgress = _bufferSize / fileSize;
+            downloadCallback!(_downloadProgress, null);
+          }else{
+            throw DownloadErrorException(_errorMsg);
           }
         } else {
-          var last = fileSize % _chunkSize;
-          var chunkCount = fileSize ~/ _chunkSize;
+          var chunkSize = max(_minChunkSize, fileSize~/100) ;
+          var last = fileSize % chunkSize;
+          var chunkCount = fileSize ~/ chunkSize;
           for (var i = 0; i < chunkCount; i++) {
-            var start = i * _chunkSize;
-            var end = start + _chunkSize - 1;
+            var start = i * chunkSize;
+            var end = start + chunkSize - 1;
             await _downloadChunk(start, end);
             if (_error) {
-              break;
+              throw DownloadErrorException(_errorMsg);
             }
             if (downloadCallback != null) {
-              var progress = _bufferSize / fileSize;
-              downloadCallback!(progress);
+              _downloadProgress = _bufferSize / fileSize;
+              downloadCallback!(_downloadProgress, null);
             }
           }
           if (!_error && last > 0) {
-            var start = chunkCount * _chunkSize;
+            var start = chunkCount * chunkSize;
             var end = start + last - 1;
             await _downloadChunk(start, end);
             if (!_error && downloadCallback != null) {
-              var progress = _bufferSize / fileSize;
-              downloadCallback!(progress);
+              _downloadProgress = _bufferSize / fileSize;
+              downloadCallback!(_downloadProgress, null);
+            }else{
+              throw DownloadErrorException(_errorMsg);
             }
           }
         }
       }
-    } catch (ex) {
+    } on DownloadErrorException catch (e) {
+      if (!_error && downloadCallback != null) {
+        downloadCallback!(_downloadProgress, e);
+      }
+    } on Exception catch (e) {
       _error = true;
-      _errorMsg = ex.toString();
+      _errorMsg = e.toString();
+      if (!_error && downloadCallback != null) {
+        downloadCallback!(_downloadProgress, DownloadErrorException(_errorMsg));
+      }
     }
   }
 

lib/us/vid_us_image_data.dart

@@ -74,8 +74,11 @@ class VidUsImageData {
   }
 }
 
+///Raised when getting data from the downloaded data timeout. depends on the readHeaderTimeout and
+///readImageTimeout parameters.
 class ReadTimeoutException implements Exception {}
 
+///Raised when the Http operation already closed.
 class AlreadyClosedException implements Exception {}
 
 ///Only suport read for now.
@@ -90,6 +93,7 @@ class HttpVidUsImageData {
   late Uint8List _extendedData;
   late int _readHeaderTimeout;
   late int _readImageTimeout;
+  late bool _initialized;
   late bool _closed;
 
   final Duration delayDuration = const Duration(milliseconds: 10);
@@ -107,45 +111,60 @@ class HttpVidUsImageData {
   /// Gets the image format of this image data.
   VidUsImageFormat get imageFormat => _imageFormat;
 
-  /// Gets or sets the extended data.
+  /// Gets the extended data.
   Uint8List get extendedData => _extendedData;
 
+  /// Gets the initialized state.
+  bool get initialized => _initialized;
+
   /// Create a VINNO Image Data.
-  /// [readHeaderTimeout] is the timeout value of reading header and probe information etc...
+  /// [readHeaderTimeout] is the timeout value of reading header and probe information etc..., we need give as much time as possible
+  /// to let the reader read the header.
   /// [readImageTimeout] is the timeout value of reading one frame.
-  HttpVidUsImageData(String url, {DownloadCallback? downloadCallback, int readHeaderTimeout = 1000, int readImageTimeout = 300}) {
+  /// [minChunkSize] The min download chunk size, set to a large value may speedup the download speed, but will cause the progress not smooth.
+  HttpVidUsImageData(String url, {DownloadCallback? downloadCallback, int minChunkSize = 65536, int readHeaderTimeout = 3000, int readImageTimeout = 500}) {
+    _initialized = false;
     _closed = false;
     _readHeaderTimeout = readHeaderTimeout;
     _readImageTimeout = readImageTimeout;
-    _reader = VidUsDataHttpReader(url, downloadCallback: downloadCallback);
+    _reader = VidUsDataHttpReader(url, downloadCallback: downloadCallback, minChunkSize: minChunkSize);
+  }
+
+  ///Get the downloaded data of this HttpVidUsImageData
+  Uint8List getDownloadedData() {
+    return _reader.toBytes();
   }
 
-  //Initialize the StreamedVidUsImageData
+  ///Initialize the HttpVidUsImageData, must be called firstly.
   Future initialize() async {
-    var header = await _readHeader();
-    if (header != header) {
-      throw Exception("The input data is not a VID data.");
-    }
-    _version = await _readVersion();
-    //Get probe info
-    _probe = await _readProbe();
-    _imageFormat = await _readImageFormat();
-    _extendedData = await _readExtendedData();
-    _imagePositionList = [];
-    var imagePositionListData = await _readImagePositionListData();
-    _imageCount = imagePositionListData.length ~/ 8;
-    var imagePositionReader = VidUsDataReader(imagePositionListData);
-    for (var i = 0; i < _imageCount; i++) {
-      _imagePositionList.add(imagePositionReader.readInt64V2());
+    if (!_initialized) {
+      var header = await _readHeader();
+      if (header != header) {
+        throw Exception("The input data is not a VID data.");
+      }
+      _version = await _readVersion();
+      //Get probe info
+      _probe = await _readProbe();
+      _imageFormat = await _readImageFormat();
+      _extendedData = await _readExtendedData();
+      _imagePositionList = [];
+      var imagePositionListData = await _readImagePositionListData();
+      _imageCount = imagePositionListData.length ~/ 8;
+      var imagePositionReader = VidUsDataReader(imagePositionListData);
+      for (var i = 0; i < _imageCount; i++) {
+        _imagePositionList.add(imagePositionReader.readInt64V2());
+      }
+      _initialized = true;
     }
   }
 
+  ///Close the HttpVidUsImageData, it will force close the download operation and reading operation.
   void close() {
     _closed = true;
     _reader.close();
   }
 
-  //Read header from http data.
+  ///Read header from http data.
   Future<String> _readHeader() async {
     var timeout = 0;
     while (!_closed) {
@@ -167,7 +186,7 @@ class HttpVidUsImageData {
     throw AlreadyClosedException();
   }
 
-  //Read the version from http data.
+  ///Read the version from http data.
   Future<int> _readVersion() async {
     var timeout = 0;
     while (!_closed) {
@@ -189,7 +208,7 @@ class HttpVidUsImageData {
     throw AlreadyClosedException();
   }
 
-  //Read the probe info from http data.
+  ///Read the probe info from http data.
   Future<VidUsProbe> _readProbe() async {
     var timeout = 0;
     while (!_closed) {
@@ -211,7 +230,7 @@ class HttpVidUsImageData {
     throw AlreadyClosedException();
   }
 
-  //Read the image format from http data.
+  ///Read the image format from http data.
   Future<VidUsImageFormat> _readImageFormat() async {
     var timeout = 0;
     while (!_closed) {
@@ -232,7 +251,7 @@ class HttpVidUsImageData {
     throw AlreadyClosedException();
   }
 
-  //Read extended data from http data.
+  ///Read extended data from http data.
   Future<Uint8List> _readExtendedData() async {
     var timeout = 0;
     while (!_closed) {
@@ -253,7 +272,7 @@ class HttpVidUsImageData {
     throw AlreadyClosedException();
   }
 
-  //Read the image positions data from http data.
+  ///Read the image positions data from http data.
   Future<Uint8List> _readImagePositionListData() async {
     var timeout = 0;
     while (!_closed) {
@@ -297,6 +316,6 @@ class HttpVidUsImageData {
         }
       }
     }
-      throw AlreadyClosedException();
+    throw AlreadyClosedException();
   }
 }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: vid
 description: vid data reader/writer for flutter.
-version: 1.0.1
+version: 1.0.2
 homepage:
 
 environment:
@@ -10,7 +10,3 @@ dependencies:
   flutter:
     sdk: flutter
   dio: ^4.0.6
-
-dev_dependencies:
-  flutter_test:
-    sdk: flutter