You are given a set of functio

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You are given a set of functions:
```
int open_port();
opens a serial port and returns 0 if everything ok (or -1 if error)

int read_port(char *buf, int buf_size)
which reads data from a serial port and stores it to 'buf' of size 'buf_size' or blocks until the data is available and returns the number of bytes read (or -1 if error occurred)

void close_port();
closes a serial port connection
```
Design a class:
```
class SerialConnection {
public:
     using ByteHook = std::function<void(char)>;

     SerialConnection(ByteHook callback);
....    
};
```
which should read data from the serial port asynchronously and send it to the callback function ByteHook byte by byte (e.g., for decoding).

Note that if you don't call 'read_port' often enough, the underlying system buffer might get full and some bytes will get lost..

Which data structures / sync primitives you are going to use ?
- pavel.em August 24, 2018 in United States | Report Duplicate | Flag | PURGE
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of 0 vote

in C#:

class SerialConnection
        {
	        private Action<char> receiveByteFunction;
            bool portOpen = false;
            Thread receivingThread;
            Thread callback;
            Queue<char> queue = new Queue<char>();

            public SerialConnection(Action<char> receiveByteFunction)
            {
                this.receiveByteFunction = receiveByteFunction;
                callback = new Thread(SendToDispatcher);
                callback.Start();
            }

            ~SerialConnection()
            {
                callback.Abort();
            }

            public void StartReceiving()
            {
                if (open_port() == 0)
                {
                    portOpen = true;
                    receivingThread = new Thread(ReadUntilDone);
                    receivingThread.Start();
                }
                else
                {
                    throw new Exception("port couldn't be opened");
                }
            }

            int bufferSize = 512;

            public void Cancel()
            {
                if (portOpen)
                {
                    portOpen = false;
                    close_port();
                }
                receivingThread.Abort();
            }

            public void ReadUntilDone()
            {
                char[] buff = new char[bufferSize];
                int charReceived;

                //read all (foreach)
                charReceived = read_port(buff, bufferSize);
                while (charReceived > 0)
                {

                    for (int i = 0; i < bufferSize; i++)
                    {
                        lock (queue)
                        {
                            queue.Enqueue(buff[i]);
                            Monitor.Pulse(queue);
                        }
                    }

                    charReceived = read_port(buff, bufferSize);
                }
            }

            public void SendToDispatcher()
            {
                char toSend;
                bool hasData;

                while (true)
                {

                    lock (queue)
                    {
                        hasData = queue.TryDequeue(out toSend);
                        if (!hasData)
                            Monitor.Wait(queue);
                    }

                    if (hasData)
                    {
                        receiveByteFunction(toSend);
                    }
                }
            }
        }

- Anonymous August 02, 2019 | Flag Reply

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