Rename our allwpilib (which is now 2020) to not have 2019 in the name

Change-Id: I3c07f85ed32ab8b97db765a9b43f2a6ce7da964a
diff --git a/wpilibc/src/main/native/cpp/PIDBase.cpp b/wpilibc/src/main/native/cpp/PIDBase.cpp
new file mode 100644
index 0000000..c8f6fed
--- /dev/null
+++ b/wpilibc/src/main/native/cpp/PIDBase.cpp
@@ -0,0 +1,353 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2008-2019 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "frc/PIDBase.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include <hal/FRCUsageReporting.h>
+
+#include "frc/PIDOutput.h"
+#include "frc/smartdashboard/SendableBuilder.h"
+#include "frc/smartdashboard/SendableRegistry.h"
+
+using namespace frc;
+
+template <class T>
+constexpr const T& clamp(const T& value, const T& low, const T& high) {
+  return std::max(low, std::min(value, high));
+}
+
+PIDBase::PIDBase(double Kp, double Ki, double Kd, PIDSource& source,
+                 PIDOutput& output)
+    : PIDBase(Kp, Ki, Kd, 0.0, source, output) {}
+
+PIDBase::PIDBase(double Kp, double Ki, double Kd, double Kf, PIDSource& source,
+                 PIDOutput& output) {
+  m_P = Kp;
+  m_I = Ki;
+  m_D = Kd;
+  m_F = Kf;
+
+  m_pidInput = &source;
+  m_filter = LinearFilter<double>::MovingAverage(1);
+
+  m_pidOutput = &output;
+
+  m_setpointTimer.Start();
+
+  static int instances = 0;
+  instances++;
+  HAL_Report(HALUsageReporting::kResourceType_PIDController, instances);
+  SendableRegistry::GetInstance().Add(this, "PIDController", instances);
+}
+
+double PIDBase::Get() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_result;
+}
+
+void PIDBase::SetContinuous(bool continuous) {
+  std::scoped_lock lock(m_thisMutex);
+  m_continuous = continuous;
+}
+
+void PIDBase::SetInputRange(double minimumInput, double maximumInput) {
+  {
+    std::scoped_lock lock(m_thisMutex);
+    m_minimumInput = minimumInput;
+    m_maximumInput = maximumInput;
+    m_inputRange = maximumInput - minimumInput;
+  }
+
+  SetSetpoint(m_setpoint);
+}
+
+void PIDBase::SetOutputRange(double minimumOutput, double maximumOutput) {
+  std::scoped_lock lock(m_thisMutex);
+  m_minimumOutput = minimumOutput;
+  m_maximumOutput = maximumOutput;
+}
+
+void PIDBase::SetPID(double p, double i, double d) {
+  {
+    std::scoped_lock lock(m_thisMutex);
+    m_P = p;
+    m_I = i;
+    m_D = d;
+  }
+}
+
+void PIDBase::SetPID(double p, double i, double d, double f) {
+  std::scoped_lock lock(m_thisMutex);
+  m_P = p;
+  m_I = i;
+  m_D = d;
+  m_F = f;
+}
+
+void PIDBase::SetP(double p) {
+  std::scoped_lock lock(m_thisMutex);
+  m_P = p;
+}
+
+void PIDBase::SetI(double i) {
+  std::scoped_lock lock(m_thisMutex);
+  m_I = i;
+}
+
+void PIDBase::SetD(double d) {
+  std::scoped_lock lock(m_thisMutex);
+  m_D = d;
+}
+
+void PIDBase::SetF(double f) {
+  std::scoped_lock lock(m_thisMutex);
+  m_F = f;
+}
+
+double PIDBase::GetP() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_P;
+}
+
+double PIDBase::GetI() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_I;
+}
+
+double PIDBase::GetD() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_D;
+}
+
+double PIDBase::GetF() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_F;
+}
+
+void PIDBase::SetSetpoint(double setpoint) {
+  {
+    std::scoped_lock lock(m_thisMutex);
+
+    if (m_maximumInput > m_minimumInput) {
+      if (setpoint > m_maximumInput)
+        m_setpoint = m_maximumInput;
+      else if (setpoint < m_minimumInput)
+        m_setpoint = m_minimumInput;
+      else
+        m_setpoint = setpoint;
+    } else {
+      m_setpoint = setpoint;
+    }
+  }
+}
+
+double PIDBase::GetSetpoint() const {
+  std::scoped_lock lock(m_thisMutex);
+  return m_setpoint;
+}
+
+double PIDBase::GetDeltaSetpoint() const {
+  std::scoped_lock lock(m_thisMutex);
+  return (m_setpoint - m_prevSetpoint) / m_setpointTimer.Get();
+}
+
+double PIDBase::GetError() const {
+  double setpoint = GetSetpoint();
+  {
+    std::scoped_lock lock(m_thisMutex);
+    return GetContinuousError(setpoint - m_pidInput->PIDGet());
+  }
+}
+
+double PIDBase::GetAvgError() const { return GetError(); }
+
+void PIDBase::SetPIDSourceType(PIDSourceType pidSource) {
+  m_pidInput->SetPIDSourceType(pidSource);
+}
+
+PIDSourceType PIDBase::GetPIDSourceType() const {
+  return m_pidInput->GetPIDSourceType();
+}
+
+void PIDBase::SetTolerance(double percent) {
+  std::scoped_lock lock(m_thisMutex);
+  m_toleranceType = kPercentTolerance;
+  m_tolerance = percent;
+}
+
+void PIDBase::SetAbsoluteTolerance(double absTolerance) {
+  std::scoped_lock lock(m_thisMutex);
+  m_toleranceType = kAbsoluteTolerance;
+  m_tolerance = absTolerance;
+}
+
+void PIDBase::SetPercentTolerance(double percent) {
+  std::scoped_lock lock(m_thisMutex);
+  m_toleranceType = kPercentTolerance;
+  m_tolerance = percent;
+}
+
+void PIDBase::SetToleranceBuffer(int bufLength) {
+  std::scoped_lock lock(m_thisMutex);
+  m_filter = LinearFilter<double>::MovingAverage(bufLength);
+}
+
+bool PIDBase::OnTarget() const {
+  double error = GetError();
+
+  std::scoped_lock lock(m_thisMutex);
+  switch (m_toleranceType) {
+    case kPercentTolerance:
+      return std::fabs(error) < m_tolerance / 100 * m_inputRange;
+      break;
+    case kAbsoluteTolerance:
+      return std::fabs(error) < m_tolerance;
+      break;
+    case kNoTolerance:
+      // TODO: this case needs an error
+      return false;
+  }
+  return false;
+}
+
+void PIDBase::Reset() {
+  std::scoped_lock lock(m_thisMutex);
+  m_prevError = 0;
+  m_totalError = 0;
+  m_result = 0;
+}
+
+void PIDBase::PIDWrite(double output) { SetSetpoint(output); }
+
+void PIDBase::InitSendable(SendableBuilder& builder) {
+  builder.SetSmartDashboardType("PIDController");
+  builder.SetSafeState([=]() { Reset(); });
+  builder.AddDoubleProperty("p", [=]() { return GetP(); },
+                            [=](double value) { SetP(value); });
+  builder.AddDoubleProperty("i", [=]() { return GetI(); },
+                            [=](double value) { SetI(value); });
+  builder.AddDoubleProperty("d", [=]() { return GetD(); },
+                            [=](double value) { SetD(value); });
+  builder.AddDoubleProperty("f", [=]() { return GetF(); },
+                            [=](double value) { SetF(value); });
+  builder.AddDoubleProperty("setpoint", [=]() { return GetSetpoint(); },
+                            [=](double value) { SetSetpoint(value); });
+}
+
+void PIDBase::Calculate() {
+  if (m_pidInput == nullptr || m_pidOutput == nullptr) return;
+
+  bool enabled;
+  {
+    std::scoped_lock lock(m_thisMutex);
+    enabled = m_enabled;
+  }
+
+  if (enabled) {
+    double input;
+
+    // Storage for function inputs
+    PIDSourceType pidSourceType;
+    double P;
+    double I;
+    double D;
+    double feedForward = CalculateFeedForward();
+    double minimumOutput;
+    double maximumOutput;
+
+    // Storage for function input-outputs
+    double prevError;
+    double error;
+    double totalError;
+
+    {
+      std::scoped_lock lock(m_thisMutex);
+
+      input = m_filter.Calculate(m_pidInput->PIDGet());
+
+      pidSourceType = m_pidInput->GetPIDSourceType();
+      P = m_P;
+      I = m_I;
+      D = m_D;
+      minimumOutput = m_minimumOutput;
+      maximumOutput = m_maximumOutput;
+
+      prevError = m_prevError;
+      error = GetContinuousError(m_setpoint - input);
+      totalError = m_totalError;
+    }
+
+    // Storage for function outputs
+    double result;
+
+    if (pidSourceType == PIDSourceType::kRate) {
+      if (P != 0) {
+        totalError =
+            clamp(totalError + error, minimumOutput / P, maximumOutput / P);
+      }
+
+      result = D * error + P * totalError + feedForward;
+    } else {
+      if (I != 0) {
+        totalError =
+            clamp(totalError + error, minimumOutput / I, maximumOutput / I);
+      }
+
+      result =
+          P * error + I * totalError + D * (error - prevError) + feedForward;
+    }
+
+    result = clamp(result, minimumOutput, maximumOutput);
+
+    {
+      // Ensures m_enabled check and PIDWrite() call occur atomically
+      std::scoped_lock pidWriteLock(m_pidWriteMutex);
+      std::unique_lock mainLock(m_thisMutex);
+      if (m_enabled) {
+        // Don't block other PIDBase operations on PIDWrite()
+        mainLock.unlock();
+
+        m_pidOutput->PIDWrite(result);
+      }
+    }
+
+    std::scoped_lock lock(m_thisMutex);
+    m_prevError = m_error;
+    m_error = error;
+    m_totalError = totalError;
+    m_result = result;
+  }
+}
+
+double PIDBase::CalculateFeedForward() {
+  if (m_pidInput->GetPIDSourceType() == PIDSourceType::kRate) {
+    return m_F * GetSetpoint();
+  } else {
+    double temp = m_F * GetDeltaSetpoint();
+    m_prevSetpoint = m_setpoint;
+    m_setpointTimer.Reset();
+    return temp;
+  }
+}
+
+double PIDBase::GetContinuousError(double error) const {
+  if (m_continuous && m_inputRange != 0) {
+    error = std::fmod(error, m_inputRange);
+    if (std::fabs(error) > m_inputRange / 2) {
+      if (error > 0) {
+        return error - m_inputRange;
+      } else {
+        return error + m_inputRange;
+      }
+    }
+  }
+
+  return error;
+}