Squashed 'third_party/allwpilib_2016/' content from commit 7f61816

Change-Id: If9d9245880859cdf580f5d7f77045135d0521ce7
git-subtree-dir: third_party/allwpilib_2016
git-subtree-split: 7f618166ed253a24629934fcf89c3decb0528a3b
diff --git a/wpilibc/shared/include/PIDController.h b/wpilibc/shared/include/PIDController.h
new file mode 100644
index 0000000..301356c
--- /dev/null
+++ b/wpilibc/shared/include/PIDController.h
@@ -0,0 +1,132 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2008. 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 $(WIND_BASE)/WPILib.  */
+/*----------------------------------------------------------------------------*/
+#pragma once
+
+#include "Base.h"
+#include "Controller.h"
+#include "LiveWindow/LiveWindow.h"
+#include "PIDInterface.h"
+#include "PIDSource.h"
+#include "Notifier.h"
+#include "HAL/cpp/priority_mutex.h"
+
+#include <memory>
+
+#include <atomic>
+#include <queue>
+
+class PIDOutput;
+
+/**
+ * Class implements a PID Control Loop.
+ *
+ * Creates a separate thread which reads the given PIDSource and takes
+ * care of the integral calculations, as well as writing the given
+ * PIDOutput
+ */
+class PIDController : public LiveWindowSendable,
+                      public PIDInterface,
+                      public ITableListener {
+ public:
+  PIDController(float p, float i, float d, PIDSource *source, PIDOutput *output,
+                float period = 0.05);
+  PIDController(float p, float i, float d, float f, PIDSource *source,
+                PIDOutput *output, float period = 0.05);
+  virtual ~PIDController();
+
+  PIDController(const PIDController&) = delete;
+  PIDController& operator=(const PIDController) = delete;
+
+  virtual float Get() const;
+  virtual void SetContinuous(bool continuous = true);
+  virtual void SetInputRange(float minimumInput, float maximumInput);
+  virtual void SetOutputRange(float minimumOutput, float maximumOutput);
+  virtual void SetPID(double p, double i, double d) override;
+  virtual void SetPID(double p, double i, double d, double f);
+  virtual double GetP() const override;
+  virtual double GetI() const override;
+  virtual double GetD() const override;
+  virtual double GetF() const;
+
+  virtual void SetSetpoint(float setpoint) override;
+  virtual double GetSetpoint() const override;
+
+  virtual float GetError() const;
+  virtual float GetAvgError() const;
+
+  virtual void SetPIDSourceType(PIDSourceType pidSource);
+  virtual PIDSourceType GetPIDSourceType() const;
+
+  virtual void SetTolerance(float percent);
+  virtual void SetAbsoluteTolerance(float absValue);
+  virtual void SetPercentTolerance(float percentValue);
+  virtual void SetToleranceBuffer(unsigned buf = 1);
+  virtual bool OnTarget() const;
+
+  virtual void Enable() override;
+  virtual void Disable() override;
+  virtual bool IsEnabled() const override;
+
+  virtual void Reset() override;
+
+  virtual void InitTable(std::shared_ptr<ITable> table) override;
+
+ protected:
+  PIDSource *m_pidInput;
+  PIDOutput *m_pidOutput;
+
+  std::shared_ptr<ITable> m_table;
+  virtual void Calculate();
+
+ private:
+  float m_P;              // factor for "proportional" control
+  float m_I;              // factor for "integral" control
+  float m_D;              // factor for "derivative" control
+  float m_F;              // factor for "feed forward" control
+  float m_maximumOutput = 1.0;  // |maximum output|
+  float m_minimumOutput = -1.0;  // |minimum output|
+  float m_maximumInput = 0;   // maximum input - limit setpoint to this
+  float m_minimumInput = 0;   // minimum input - limit setpoint to this
+  bool m_continuous = false;      // do the endpoints wrap around? eg. Absolute encoder
+  bool m_enabled = false;  // is the pid controller enabled
+  float m_prevInput = 0;  // the prior sensor input (used to compute velocity)
+  double m_totalError = 0;  // the sum of the errors for use in the integral calc
+  enum {
+    kAbsoluteTolerance,
+    kPercentTolerance,
+    kNoTolerance
+  } m_toleranceType = kNoTolerance;
+
+  // the percetage or absolute error that is considered on target.
+  float m_tolerance = 0.05;
+  float m_setpoint = 0;
+  float m_error = 0;
+  float m_result = 0;
+  float m_period;
+
+  // Length of buffer for averaging for tolerances.
+  std::atomic<unsigned> m_bufLength{1};
+  std::queue<double> m_buf;
+  double m_bufTotal = 0;
+
+  mutable priority_mutex m_mutex;
+
+  std::unique_ptr<Notifier> m_controlLoop;
+
+  void Initialize(float p, float i, float d, float f, PIDSource *source,
+                  PIDOutput *output, float period = 0.05);
+  static void CallCalculate(void *controller);
+
+  virtual std::shared_ptr<ITable> GetTable() const override;
+  virtual std::string GetSmartDashboardType() const override;
+  virtual void ValueChanged(ITable *source, llvm::StringRef key,
+                            std::shared_ptr<nt::Value> value,
+                            bool isNew) override;
+  virtual void UpdateTable() override;
+  virtual void StartLiveWindowMode() override;
+  virtual void StopLiveWindowMode() override;
+};