tidstagning/Relay.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO.Ports;
using System.Threading;

namespace Tidstagning
{
    class Relay
    {
        SerialPort com = new SerialPort();

        struct SignalSpec
        {
            public uint duration;
            public bool output_on;
        };
        Queue<SignalSpec> signals = new Queue<SignalSpec>();
        bool processing_queue;

        public Relay()
        {
        }

        public bool Open(string ComPort)
        {
            if (com.IsOpen)
            {
                Close();
            }

            com.PortName = ComPort;
            com.BaudRate = 9600;
            try
            {
                com.Open();
                return true;
            }
            catch (ArgumentException)
            {
                return false;
            }
        }

        private void On()
        {
            Debug.WriteLine("Output on");
            Set(0x00, 0x01);
        }

        private void Off()
        {
            Debug.WriteLine("Output off");
            Set(0x00, 0x00);
        }


        /**
         * Sound the horn for a given time
         * Uses a thread to postpone the off call.
         */
        public void Sound(uint time)
        {
            if (!com.IsOpen)
            {
                Debug.WriteLine("ComPort not open");
                return;
            }

            Debug.WriteLine("Requesting horn for: " + time.ToString(new CultureInfo("da-DK")) + "ms");
            SignalSpec on_signal;
            on_signal.duration = time;
            on_signal.output_on = true;

            signals.Enqueue(on_signal);

            SignalSpec gracePeriod;
            gracePeriod.duration = time;
            gracePeriod.output_on = false;
            signals.Enqueue(gracePeriod);
            if (processing_queue == false)
            {
                Run();
            }
        }

        private void Run()
        {
            if (signals.Count == 0)
            {
                processing_queue = false;
            }
            else
            {
                processing_queue = true;
                SignalSpec signal = signals.Peek();

                if (signal.output_on)
                {
                    On();
                }
                else
                {
                    Off();
                }

                System.Threading.Timer cooldownTimer = new System.Threading.Timer(x =>
                {
                    signals.Dequeue();
                    Run();
                }, null, signal.duration, Timeout.Infinite);
            }
        }

        private void Set(int output, byte state)
        {
            byte[] command = { 0xff, 0x01, state };
            if (com.IsOpen)
            {
                Debug.WriteLine("COM: " + com.PortName + " Write: 0x" + Convert.ToString(command[2], 16));
                com.Write(command, 0, 3);
            }
        }
        public void Close()
        {
            if (com.IsOpen)
            {
                Off(); //Make sure the horn is off before closing the com port...
                com.Close();
            }
        }

        public static string[] GetPorts()
        {
            string[] ports;

            if (SerialPort.GetPortNames().Length != 0)
            {
                ports = SerialPort.GetPortNames();
            }
            else
            {
                ports = new string[] { "N/A" };
            }
            return ports;
        }
    }
}