protected override void RetrieveMessagesImplementation()

in FixAntenna/NetCore/FixEngine/Storage/File/SlicedIndexedMessageStorage.cs [78:166]
79 lines of code
13 McCabe index (conditional complexity)

		protected override void RetrieveMessagesImplementation(long from, long to, IMessageStorageListener listener, bool blocking)
		{
			if (from < 1)
			{
				throw new ArgumentException("From can't be <1");
			}

			if (to < 1)
			{
				throw new ArgumentException("To can't be <1");
			}

			FileStream readFile = null;
			var currentChunk = -1;
			try
			{
				for (var i = from; i <= to; i++)
				{
					var indexBlock = new ByteBuffer(IndexLength);
					if (IsClosed)
					{
						throw new InvalidOperationException("Storage is closed");
					}

					var len = -1;
					lock (_indexLock)
					{
						_index.Position = (i - 1) * IndexLength;
						var tempIndexData = new byte[IndexLength];
						len = _index.Read(tempIndexData, 0, tempIndexData.Length);
						indexBlock.Put(tempIndexData, 0, len);
					}

					if (len <= 0)
					{
						return; //no more data
					}

					indexBlock.Position = 0;
					var chunkId = indexBlock.GetIntBe();
					var messagePosition = indexBlock.GetLongBe();
					var messageLength = indexBlock.GetIntBe();
					if (currentChunk != chunkId && chunkId != 0)
					{
						// chunkId==0 it is means that there is gap.
						currentChunk = chunkId;
						if (readFile != null)
						{
							readFile.Close();
							readFile = null;
						}

						readFile = new FileStream(FileManager.GetFileName(currentChunk), FileMode.Open, FileAccess.Read,
							FileShare.ReadWrite);
					}

					var message = ReadFromStorage(readFile, messagePosition, messageLength);

					NotifyListener(listener, blocking, message);
				}
			}
			catch (Exception e)
			{
				if (Log.IsWarnEnabled)
				{
					if (Log.IsDebugEnabled)
					{
						Log.Warn("Problem in retrieving messages from indexed message storage: " + e.ToString(), e);
					}
					else
					{
						Log.Warn("Problem in retrieving messages from indexed message storage: " + e.ToString());
					}
				}

				if (IsClosed)
				{
					throw new StorageClosedException("Storage is closed. Cause: " + e.Message);
				}
				else
				{
					throw new IOException(e.Message);
				}
			}
			finally
			{
				readFile?.Close();
			}
		}