Fixed FRCSim artf2599.

Made the wpilibC++Sim codebase's motor control as
similar to the wpilibC++ motor control as possible.

Change-Id: I5510d952cb40c4a3def210f46a566d7102d604ee

wpilibc/wpilibC++Sim/src/SafePWM.cpp

@@ -0,0 +1,106 @@
+/*----------------------------------------------------------------------------*/
+/* 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.  */
+/*----------------------------------------------------------------------------*/
+
+#include "SafePWM.h"
+
+#include "MotorSafetyHelper.h"
+
+/**
+ * Initialize a SafePWM object by setting defaults
+ */
+void SafePWM::InitSafePWM()
+{
+	m_safetyHelper = new MotorSafetyHelper(this);
+	m_safetyHelper->SetSafetyEnabled(false);
+}
+
+/**
+ * Constructor for a SafePWM object taking a channel number.
+ * @param channel The PWM channel number (0..19).
+ */
+SafePWM::SafePWM(uint32_t channel): PWM(channel)
+{
+	InitSafePWM();
+}
+
+SafePWM::~SafePWM()
+{
+	delete m_safetyHelper;
+}
+
+/*
+ * Set the expiration time for the PWM object
+ * @param timeout The timeout (in seconds) for this motor object
+ */
+void SafePWM::SetExpiration(float timeout)
+{
+	m_safetyHelper->SetExpiration(timeout);
+}
+
+/**
+ * Return the expiration time for the PWM object.
+ * @returns The expiration time value.
+ */
+float SafePWM::GetExpiration()
+{
+	return m_safetyHelper->GetExpiration();
+}
+
+/**
+ * Check if the PWM object is currently alive or stopped due to a timeout.
+ * @returns a bool value that is true if the motor has NOT timed out and should still
+ * be running.
+ */
+bool SafePWM::IsAlive()
+{
+	return m_safetyHelper->IsAlive();
+}
+
+/**
+ * Stop the motor associated with this PWM object.
+ * This is called by the MotorSafetyHelper object when it has a timeout for this PWM and needs to
+ * stop it from running.
+ */
+void SafePWM::StopMotor()
+{
+	SetRaw(kPwmDisabled);
+}
+
+/**
+ * Enable/disable motor safety for this device
+ * Turn on and off the motor safety option for this PWM object.
+ * @param enabled True if motor safety is enforced for this object
+ */
+void SafePWM::SetSafetyEnabled(bool enabled)
+{
+	m_safetyHelper->SetSafetyEnabled(enabled);
+}
+
+/**
+ * Check if motor safety is enabled for this object
+ * @returns True if motor safety is enforced for this object
+ */
+bool SafePWM::IsSafetyEnabled()
+{
+	return m_safetyHelper->IsSafetyEnabled();
+}
+
+void SafePWM::GetDescription(char *desc)
+{
+	sprintf(desc, "PWM %d", GetChannel());
+}
+
+/**
+ * Feed the MotorSafety timer when setting the speed.
+ * This method is called by the subclass motor whenever it updates its speed, thereby reseting
+ * the timeout value.
+ * @param speed Value to pass to the PWM class
+ */
+void SafePWM::SetSpeed(float speed)
+{
+	PWM::SetSpeed(speed);
+	m_safetyHelper->Feed();
+}