Add DutyCycleEncoder and AnalogEncoder (#2040)

wpilibc/src/main/native/include/frc/AnalogEncoder.h

@@ -0,0 +1,126 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 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 <memory>
+
+#include <hal/SimDevice.h>
+#include <hal/Types.h>
+#include <units/units.h>
+
+#include "frc/AnalogTrigger.h"
+#include "frc/Counter.h"
+#include "frc/ErrorBase.h"
+#include "frc/smartdashboard/Sendable.h"
+#include "frc/smartdashboard/SendableHelper.h"
+
+namespace frc {
+class AnalogInput;
+
+/**
+ * Class for supporting continuous analog encoders, such as the US Digital MA3.
+ */
+class AnalogEncoder : public ErrorBase,
+                      public Sendable,
+                      public SendableHelper<AnalogEncoder> {
+ public:
+  /**
+   * Construct a new AnalogEncoder attached to a specific AnalogInput.
+   *
+   * @param analogInput the analog input to attach to
+   */
+  explicit AnalogEncoder(AnalogInput& analogInput);
+
+  /**
+   * Construct a new AnalogEncoder attached to a specific AnalogInput.
+   *
+   * @param analogInput the analog input to attach to
+   */
+  explicit AnalogEncoder(AnalogInput* analogInput);
+
+  /**
+   * Construct a new AnalogEncoder attached to a specific AnalogInput.
+   *
+   * @param analogInput the analog input to attach to
+   */
+  explicit AnalogEncoder(std::shared_ptr<AnalogInput> analogInput);
+
+  ~AnalogEncoder() override = default;
+
+  AnalogEncoder(AnalogEncoder&&) = default;
+  AnalogEncoder& operator=(AnalogEncoder&&) = default;
+
+  /**
+   * Reset the Encoder distance to zero.
+   */
+  void Reset();
+
+  /**
+   * Get the encoder value since the last reset.
+   *
+   * This is reported in rotations since the last reset.
+   *
+   * @return the encoder value in rotations
+   */
+  units::turn_t Get() const;
+
+  /**
+   * Get the offset of position relative to the last reset.
+   *
+   * GetPositionInRotation() - GetPositionOffset() will give an encoder absolute
+   * position relative to the last reset. This could potentially be negative,
+   * which needs to be accounted for.
+   *
+   * @return the position offset
+   */
+  double GetPositionOffset() const;
+
+  /**
+   * Set the distance per rotation of the encoder. This sets the multiplier used
+   * to determine the distance driven based on the rotation value from the
+   * encoder. Set this value based on the how far the mechanism travels in 1
+   * rotation of the encoder, and factor in gearing reductions following the
+   * encoder shaft. This distance can be in any units you like, linear or
+   * angular.
+   *
+   * @param distancePerRotation the distance per rotation of the encoder
+   */
+  void SetDistancePerRotation(double distancePerRotation);
+
+  /**
+   * Get the distance per rotation for this encoder.
+   *
+   * @return The scale factor that will be used to convert rotation to useful
+   * units.
+   */
+  double GetDistancePerRotation() const;
+
+  /**
+   * Get the distance the sensor has driven since the last reset as scaled by
+   * the value from SetDistancePerRotation.
+   *
+   * @return The distance driven since the last reset
+   */
+  double GetDistance() const;
+
+  void InitSendable(SendableBuilder& builder) override;
+
+ private:
+  void Init();
+
+  std::shared_ptr<AnalogInput> m_analogInput;
+  AnalogTrigger m_analogTrigger;
+  Counter m_counter;
+  double m_positionOffset = 0;
+  double m_distancePerRotation = 1.0;
+  mutable units::turn_t m_lastPosition{0.0};
+
+  hal::SimDevice m_simDevice;
+  hal::SimDouble m_simPosition;
+};
+}  // namespace frc