Squashed 'third_party/allwpilib_2019/' content from commit bd05dfa1c

Change-Id: I2b1c2250cdb9b055133780c33593292098c375b7
git-subtree-dir: third_party/allwpilib_2019
git-subtree-split: bd05dfa1c7cca74c4fac451e7b9d6a37e7b53447
diff --git a/wpilibc/src/main/native/cpp/Ultrasonic.cpp b/wpilibc/src/main/native/cpp/Ultrasonic.cpp
new file mode 100644
index 0000000..ee4f5cc
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+++ b/wpilibc/src/main/native/cpp/Ultrasonic.cpp
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+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2008-2018 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/Ultrasonic.h"
+
+#include <hal/HAL.h>
+
+#include "frc/Counter.h"
+#include "frc/DigitalInput.h"
+#include "frc/DigitalOutput.h"
+#include "frc/Timer.h"
+#include "frc/Utility.h"
+#include "frc/WPIErrors.h"
+#include "frc/smartdashboard/SendableBuilder.h"
+
+using namespace frc;
+
+// Automatic round robin mode
+std::atomic<bool> Ultrasonic::m_automaticEnabled{false};
+
+std::vector<Ultrasonic*> Ultrasonic::m_sensors;
+std::thread Ultrasonic::m_thread;
+
+Ultrasonic::Ultrasonic(int pingChannel, int echoChannel, DistanceUnit units)
+    : m_pingChannel(std::make_shared<DigitalOutput>(pingChannel)),
+      m_echoChannel(std::make_shared<DigitalInput>(echoChannel)),
+      m_counter(m_echoChannel) {
+  m_units = units;
+  Initialize();
+  AddChild(m_pingChannel);
+  AddChild(m_echoChannel);
+}
+
+Ultrasonic::Ultrasonic(DigitalOutput* pingChannel, DigitalInput* echoChannel,
+                       DistanceUnit units)
+    : m_pingChannel(pingChannel, NullDeleter<DigitalOutput>()),
+      m_echoChannel(echoChannel, NullDeleter<DigitalInput>()),
+      m_counter(m_echoChannel) {
+  if (pingChannel == nullptr || echoChannel == nullptr) {
+    wpi_setWPIError(NullParameter);
+    m_units = units;
+    return;
+  }
+  m_units = units;
+  Initialize();
+}
+
+Ultrasonic::Ultrasonic(DigitalOutput& pingChannel, DigitalInput& echoChannel,
+                       DistanceUnit units)
+    : m_pingChannel(&pingChannel, NullDeleter<DigitalOutput>()),
+      m_echoChannel(&echoChannel, NullDeleter<DigitalInput>()),
+      m_counter(m_echoChannel) {
+  m_units = units;
+  Initialize();
+}
+
+Ultrasonic::Ultrasonic(std::shared_ptr<DigitalOutput> pingChannel,
+                       std::shared_ptr<DigitalInput> echoChannel,
+                       DistanceUnit units)
+    : m_pingChannel(pingChannel),
+      m_echoChannel(echoChannel),
+      m_counter(m_echoChannel) {
+  m_units = units;
+  Initialize();
+}
+
+Ultrasonic::~Ultrasonic() {
+  // Delete the instance of the ultrasonic sensor by freeing the allocated
+  // digital channels. If the system was in automatic mode (round robin), then
+  // it is stopped, then started again after this sensor is removed (provided
+  // this wasn't the last sensor).
+
+  bool wasAutomaticMode = m_automaticEnabled;
+  SetAutomaticMode(false);
+
+  // No synchronization needed because the background task is stopped.
+  m_sensors.erase(std::remove(m_sensors.begin(), m_sensors.end(), this),
+                  m_sensors.end());
+
+  if (!m_sensors.empty() && wasAutomaticMode) {
+    SetAutomaticMode(true);
+  }
+}
+
+void Ultrasonic::Ping() {
+  wpi_assert(!m_automaticEnabled);
+
+  // Reset the counter to zero (invalid data now)
+  m_counter.Reset();
+
+  // Do the ping to start getting a single range
+  m_pingChannel->Pulse(kPingTime);
+}
+
+bool Ultrasonic::IsRangeValid() const { return m_counter.Get() > 1; }
+
+void Ultrasonic::SetAutomaticMode(bool enabling) {
+  if (enabling == m_automaticEnabled) return;  // ignore the case of no change
+
+  m_automaticEnabled = enabling;
+
+  if (enabling) {
+    /* Clear all the counters so no data is valid. No synchronization is needed
+     * because the background task is stopped.
+     */
+    for (auto& sensor : m_sensors) {
+      sensor->m_counter.Reset();
+    }
+
+    m_thread = std::thread(&Ultrasonic::UltrasonicChecker);
+
+    // TODO: Currently, lvuser does not have permissions to set task priorities.
+    // Until that is the case, uncommenting this will break user code that calls
+    // Ultrasonic::SetAutomicMode().
+    // m_task.SetPriority(kPriority);
+  } else {
+    // Wait for background task to stop running
+    if (m_thread.joinable()) {
+      m_thread.join();
+    }
+
+    // Clear all the counters (data now invalid) since automatic mode is
+    // disabled. No synchronization is needed because the background task is
+    // stopped.
+    for (auto& sensor : m_sensors) {
+      sensor->m_counter.Reset();
+    }
+  }
+}
+
+double Ultrasonic::GetRangeInches() const {
+  if (IsRangeValid())
+    return m_counter.GetPeriod() * kSpeedOfSoundInchesPerSec / 2.0;
+  else
+    return 0;
+}
+
+double Ultrasonic::GetRangeMM() const { return GetRangeInches() * 25.4; }
+
+bool Ultrasonic::IsEnabled() const { return m_enabled; }
+
+void Ultrasonic::SetEnabled(bool enable) { m_enabled = enable; }
+
+void Ultrasonic::SetDistanceUnits(DistanceUnit units) { m_units = units; }
+
+Ultrasonic::DistanceUnit Ultrasonic::GetDistanceUnits() const {
+  return m_units;
+}
+
+double Ultrasonic::PIDGet() {
+  switch (m_units) {
+    case Ultrasonic::kInches:
+      return GetRangeInches();
+    case Ultrasonic::kMilliMeters:
+      return GetRangeMM();
+    default:
+      return 0.0;
+  }
+}
+
+void Ultrasonic::SetPIDSourceType(PIDSourceType pidSource) {
+  if (wpi_assert(pidSource == PIDSourceType::kDisplacement)) {
+    m_pidSource = pidSource;
+  }
+}
+
+void Ultrasonic::InitSendable(SendableBuilder& builder) {
+  builder.SetSmartDashboardType("Ultrasonic");
+  builder.AddDoubleProperty("Value", [=]() { return GetRangeInches(); },
+                            nullptr);
+}
+
+void Ultrasonic::Initialize() {
+  bool originalMode = m_automaticEnabled;
+  SetAutomaticMode(false);  // Kill task when adding a new sensor
+  // Link this instance on the list
+  m_sensors.emplace_back(this);
+
+  m_counter.SetMaxPeriod(1.0);
+  m_counter.SetSemiPeriodMode(true);
+  m_counter.Reset();
+  m_enabled = true;  // Make it available for round robin scheduling
+  SetAutomaticMode(originalMode);
+
+  static int instances = 0;
+  instances++;
+  HAL_Report(HALUsageReporting::kResourceType_Ultrasonic, instances);
+  SetName("Ultrasonic", m_echoChannel->GetChannel());
+}
+
+void Ultrasonic::UltrasonicChecker() {
+  while (m_automaticEnabled) {
+    for (auto& sensor : m_sensors) {
+      if (!m_automaticEnabled) break;
+
+      if (sensor->IsEnabled()) {
+        sensor->m_pingChannel->Pulse(kPingTime);  // do the ping
+      }
+
+      Wait(0.1);  // wait for ping to return
+    }
+  }
+}