Microsoft.WindowsAzure.Commands.Sync.Download.BlobHandle.GetUploadableRanges C# (CSharp) Method

        public IEnumerable<IndexRange> GetUploadableRanges()
        {
            IEnumerable<IndexRange> ranges = GetPageRanges();
            ranges = Enumerable.ToList<IndexRange>(IndexRangeHelper.ChunkRangesBySize(ranges, 2 * MegaByte));
            return ranges;
        }

        public void Download()
        {
            if (parameters.OverWrite)
            {
                DeleteTempVhdIfExist(parameters.LocalFilePath);
            }
            else
            {
                if (File.Exists(parameters.LocalFilePath))
                {
                    var message = String.Format("File already exists, you can use Overwrite option to delete it:'{0}'", parameters.LocalFilePath);
                    throw new ArgumentException(message);
                }
            }

            var blobHandle = new BlobHandle(parameters.BlobUri, this.parameters.StorageAccountKey);

            if (parameters.ValidateFreeDiskSpace)
            {
                TryValidateFreeDiskSpace(parameters.LocalFilePath, blobHandle.Length);
            }

            const int megaByte = 1024 * 1024;

            var ranges         = blobHandle.GetUploadableRanges();
            var bufferManager  = BufferManager.CreateBufferManager(Int32.MaxValue, 20 * megaByte);
            var downloadStatus = new ProgressStatus(0, ranges.Sum(r => r.Length), new ComputeStats());

            Trace.WriteLine(String.Format("Total Data:{0}", ranges.Sum(r => r.Length)));

            Program.SyncOutput.WriteVerboseWithTimestamp("Downloading the blob: {0}", parameters.BlobUri.BlobName);

            var fileStreamLock = new object();

            using (new ServicePointHandler(parameters.BlobUri.Uri, parameters.ConnectionLimit))
            {
                using (ProgressTracker progressTracker = new ProgressTracker(downloadStatus, parameters.ProgressDownloadStatus, parameters.ProgressDownloadComplete))
                {
                    using (var fileStream = new FileStream(parameters.LocalFilePath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.Write, 8 * megaByte, FileOptions.WriteThrough))
                    {
                        fileStream.SetLength(0);
                        fileStream.SetLength(blobHandle.Length);

                        Task <LoopResult> task = Task <LoopResult> .Factory.StartNew(() =>
                        {
                            return(Threading.Parallel.ForEach <IndexRange, Stream>(ranges,
                                                                                   blobHandle.OpenStream,
                                                                                   (r, b) =>
                            {
                                b.Seek(r.StartIndex, SeekOrigin.Begin);

                                byte[] buffer = this.EnsureReadAsSize(b, (int)r.Length, bufferManager);

                                lock (fileStreamLock)
                                {
                                    Trace.WriteLine(String.Format("Range:{0}", r));
                                    fileStream.Seek(r.StartIndex, SeekOrigin.Begin);
                                    fileStream.Write(buffer, 0, (int)r.Length);
                                    fileStream.Flush();
                                }

                                downloadStatus.AddToProcessedBytes((int)r.Length);
                            },
                                                                                   pbwlf =>
                            {
                                pbwlf.Dispose();
                            },
                                                                                   parameters.ConnectionLimit));
                        });

                        while (!task.Wait(TimeSpan.FromSeconds(1)))
                        {
                            progressTracker.Update();
                        }

                        LoopResult lr = task.Result;

                        if (lr.IsExceptional)
                        {
                            throw new AggregateException(lr.Exceptions);
                        }
                    }
                }
            }
            Program.SyncOutput.WriteVerboseWithTimestamp("Blob downloaded successfullty: {0}", parameters.BlobUri.BlobName);
        }