Added ahal

This is a formatted copy of WPILib's default user-visible C++ API, with
a bit of completely unnecessary functionality stripped out. Most of the
stripping so far is only related to weird threading decisions.

Change-Id: Icbfd949b48cd115561862cb909bcc572aba0e753
diff --git a/frc971/wpilib/ahal/Compressor.cc b/frc971/wpilib/ahal/Compressor.cc
new file mode 100644
index 0000000..2967f05
--- /dev/null
+++ b/frc971/wpilib/ahal/Compressor.cc
@@ -0,0 +1,299 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2014-2017. 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 "frc971/wpilib/ahal/Compressor.h"
+#include "HAL/Compressor.h"
+
+#include "HAL/HAL.h"
+#include "HAL/Ports.h"
+#include "HAL/Solenoid.h"
+#include "frc971/wpilib/ahal/WPIErrors.h"
+
+using namespace frc;
+
+/**
+ * Constructor.
+ *
+ * @param module The PCM ID to use (0-62)
+ */
+Compressor::Compressor(int pcmID) : m_module(pcmID) {
+  int32_t status = 0;
+  m_compressorHandle = HAL_InitializeCompressor(m_module, &status);
+  if (status != 0) {
+    wpi_setErrorWithContextRange(status, 0, HAL_GetNumPCMModules(), pcmID,
+                                 HAL_GetErrorMessage(status));
+    return;
+  }
+  SetClosedLoopControl(true);
+}
+
+/**
+ * Starts closed-loop control. Note that closed loop control is enabled by
+ * default.
+ */
+void Compressor::Start() {
+  if (StatusIsFatal()) return;
+  SetClosedLoopControl(true);
+}
+
+/**
+ * Stops closed-loop control. Note that closed loop control is enabled by
+ * default.
+ */
+void Compressor::Stop() {
+  if (StatusIsFatal()) return;
+  SetClosedLoopControl(false);
+}
+
+/**
+ * Check if compressor output is active.
+ *
+ * @return true if the compressor is on
+ */
+bool Compressor::Enabled() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressor(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Check if the pressure switch is triggered.
+ *
+ * @return true if pressure is low
+ */
+bool Compressor::GetPressureSwitchValue() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorPressureSwitch(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query how much current the compressor is drawing.
+ *
+ * @return The current through the compressor, in amps
+ */
+double Compressor::GetCompressorCurrent() const {
+  if (StatusIsFatal()) return 0;
+  int32_t status = 0;
+  double value;
+
+  value = HAL_GetCompressorCurrent(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Enables or disables automatically turning the compressor on when the
+ * pressure is low.
+ *
+ * @param on Set to true to enable closed loop control of the compressor. False
+ *           to disable.
+ */
+void Compressor::SetClosedLoopControl(bool on) {
+  if (StatusIsFatal()) return;
+  int32_t status = 0;
+
+  HAL_SetCompressorClosedLoopControl(m_compressorHandle, on, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+}
+
+/**
+ * Returns true if the compressor will automatically turn on when the
+ * pressure is low.
+ *
+ * @return True if closed loop control of the compressor is enabled. False if
+ *         disabled.
+ */
+bool Compressor::GetClosedLoopControl() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorClosedLoopControl(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output has been disabled due to high current draw.
+ *
+ * @return true if PCM is in fault state : Compressor Drive is
+ *         disabled due to compressor current being too high.
+ */
+bool Compressor::GetCompressorCurrentTooHighFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorCurrentTooHighFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output has been disabled due to high current draw
+ * (sticky).
+ *
+ * A sticky fault will not clear on device reboot, it must be cleared through
+ * code or the webdash.
+ *
+ * @return true if PCM sticky fault is set : Compressor Drive is
+ *         disabled due to compressor current being too high.
+ */
+bool Compressor::GetCompressorCurrentTooHighStickyFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value =
+      HAL_GetCompressorCurrentTooHighStickyFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output has been disabled due to a short circuit
+ * (sticky).
+ *
+ * A sticky fault will not clear on device reboot, it must be cleared through
+ * code or the webdash.
+ *
+ * @return true if PCM sticky fault is set : Compressor output
+ *         appears to be shorted.
+ */
+bool Compressor::GetCompressorShortedStickyFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorShortedStickyFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output has been disabled due to a short circuit.
+ *
+ * @return true if PCM is in fault state : Compressor output
+ *         appears to be shorted.
+ */
+bool Compressor::GetCompressorShortedFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorShortedFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output does not appear to be wired (sticky).
+ *
+ * A sticky fault will not clear on device reboot, it must be cleared through
+ * code or the webdash.
+ *
+ * @return true if PCM sticky fault is set : Compressor does not
+ *         appear to be wired, i.e. compressor is not drawing enough current.
+ */
+bool Compressor::GetCompressorNotConnectedStickyFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorNotConnectedStickyFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Query if the compressor output does not appear to be wired.
+ *
+ * @return true if PCM is in fault state : Compressor does not
+ *         appear to be wired, i.e. compressor is not drawing enough current.
+ */
+bool Compressor::GetCompressorNotConnectedFault() const {
+  if (StatusIsFatal()) return false;
+  int32_t status = 0;
+  bool value;
+
+  value = HAL_GetCompressorNotConnectedFault(m_compressorHandle, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+
+  return value;
+}
+
+/**
+ * Clear ALL sticky faults inside PCM that Compressor is wired to.
+ *
+ * If a sticky fault is set, then it will be persistently cleared.  Compressor
+ * drive maybe momentarily disable while flags are being cleared. Care should
+ * be taken to not call this too frequently, otherwise normal compressor
+ * functionality may be prevented.
+ *
+ * If no sticky faults are set then this call will have no effect.
+ */
+void Compressor::ClearAllPCMStickyFaults() {
+  if (StatusIsFatal()) return;
+  int32_t status = 0;
+
+  HAL_ClearAllPCMStickyFaults(m_module, &status);
+
+  if (status) {
+    wpi_setWPIError(Timeout);
+  }
+}