Data commit

Task/Active-object/C-sharp/active-object.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Threading.Tasks;
+
+using static System.Diagnostics.Stopwatch;
+using static System.Math;
+using static System.Threading.Thread;
+
+class ActiveObject
+{
+    static double timeScale = 1.0 / Frequency;
+
+    Func<double, double> func;
+    Task updateTask;
+    double integral;
+    double value;
+    long timestamp0, timestamp;
+
+    public ActiveObject(Func<double, double> input)
+    {
+        timestamp0 = timestamp = GetTimestamp();
+        func = input;
+        value = func(0);
+        updateTask = Integrate();
+    }
+
+    public void ChangeInput(Func<double, double> input)
+    {
+        lock (updateTask)
+        {
+            func = input;
+        }
+    }
+
+    public double Value
+    {
+        get
+        {
+            lock (updateTask)
+            {
+                return integral;
+            }
+        }
+    }
+
+    async Task Integrate()
+    {
+        while (true)
+        {
+            await Task.Yield();
+            var newTime = GetTimestamp();
+            double newValue;
+
+            lock (updateTask)
+            {
+                newValue = func((newTime - timestamp0) * timeScale);
+                integral += (newValue + value) * (newTime - timestamp) * timeScale / 2;
+            }
+
+            timestamp = newTime;
+            value = newValue;
+        }
+    }
+}
+
+class Program
+{
+    static Func<double, double> Sine(double frequency) =>
+        t => Sin(2 * PI * frequency * t);
+
+    static void Main(string[] args)
+    {
+        var ao = new ActiveObject(Sine(0.5));
+        Sleep(TimeSpan.FromSeconds(2));
+        ao.ChangeInput(t => 0);
+        Sleep(TimeSpan.FromSeconds(0.5));
+        Console.WriteLine(ao.Value);
+    }
+}