Knowing that data from an NSStream is complete

Question

I'am sending chunks of UIImage data over MCSession with an NSStream.

When I get bytes

- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode {

   if (eventCode == NSStreamEventHasBytesAvailable) {

      // read data and append to self.data
      // how to know that self.data can be used to create UIImage

   }

}

I append them to a mutable data instance. The problem is how to know that the accumulated data represents a full image, so I can use -[UIImage initWithData:] to create it?

Answer 1

You should watch for NSStreamEventEndEncountered

Answer 2

The stream has no knowledge of its contents. If you can't rely on the stream ending to tell you that the data is complete, then you either need to use/create some protocol for the transmission that includes a "finished" signal, or just try to create the image and take appropriate action if that fails.