[wpilib] Add DutyCycleEncoderSim (#2798)

wpilibc/src/main/native/include/frc/simulation/DutyCycleEncoderSim.h

@@ -0,0 +1,49 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2020 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <hal/SimDevice.h>
+#include <units/angle.h>
+
+namespace frc {
+
+class DutyCycleEncoder;
+
+namespace sim {
+
+/**
+ * Class to control a simulated duty cycle encoder.
+ */
+class DutyCycleEncoderSim {
+ public:
+  /**
+   * Constructs from a DutyCycleEncoder object.
+   *
+   * @param dutyCycleEncoder DutyCycleEncoder to simulate
+   */
+  explicit DutyCycleEncoderSim(const DutyCycleEncoder& encoder);
+
+  /**
+   * Set the position tin turns.
+   *
+   * @param turns The position.
+   */
+  void Set(units::turn_t turns);
+
+  /**
+   * Set the position.
+   */
+  void SetDistance(double distance);
+
+ private:
+  hal::SimDouble m_simPosition;
+  hal::SimDouble m_simDistancePerRotation;
+};
+
+}  // namespace sim
+}  // namespace frc