@@ -248,12 +248,13 @@
 			_inflateStream = nil;
 
 			_state++;
 			break;
 		case OFGZIPStreamStateCRC32:
-			_bytesRead += [_stream readIntoBuffer: _buffer
-						       length: 4 - _bytesRead];
+			_bytesRead += [_stream
+			    readIntoBuffer: _buffer + _bytesRead
+				    length: 4 - _bytesRead];
 
 			if (_bytesRead < 4)
 				return 0;
 
 			CRC32 = ((uint32_t)_buffer[3] << 24) |
@@ -272,14 +273,18 @@
 			_bytesRead = 0;
 			_CRC32 = ~0;
 			_state++;
 			break;
 		case OFGZIPStreamStateUncompressedSize:
-			_bytesRead += [_stream readIntoBuffer: _buffer
-						       length: 4 - _bytesRead];
+			_bytesRead += [_stream
+			    readIntoBuffer: _buffer + _bytesRead
+				    length: 4 - _bytesRead];
+
+			if (_bytesRead < 4)
+				return 0;
 
-			uncompressedSize = ((uint32_t)_buffer[3] << 24) |
+			uncompressedSize = (_buffer[3] << 24) |
 			    (_buffer[2] << 16) | (_buffer[1] << 8) | _buffer[0];
 			if (_uncompressedSize != uncompressedSize) {
 				OFString *actual = [OFString stringWithFormat:
 				    @"%" PRIu32, _uncompressedSize];
 				OFString *expected = [OFString stringWithFormat: