[hal] Add SimValue reset() function (#3064)

This enables correct behavior for resetting incremental sensor values like
encoder counts or gyro accumulated angle with WebSockets.

hal/src/main/java/edu/wpi/first/hal/SimDeviceJNI.java

@@ -352,4 +352,13 @@ public class SimDeviceJNI extends JNIWrapper {
   public static void setSimValueBoolean(int handle, boolean value) {
     setSimValueNative(handle, HALValue.kBoolean, value ? 1 : 0, 0.0);
   }
+
+  /**
+   * Resets a simulated double or integral value to 0. Has no effect on other value types. Use this
+   * instead of Set(0) for resetting incremental sensor values like encoder counts or gyro
+   * accumulated angle to ensure correct behavior in a distributed system (e.g. WebSockets).
+   *
+   * @param handle simulated value handle
+   */
+  public static native void resetSimValue(int handle);
 }

hal/src/main/java/edu/wpi/first/hal/SimDouble.java

@@ -32,4 +32,13 @@ public class SimDouble extends SimValue {
   public void set(double value) {
     SimDeviceJNI.setSimValueDouble(m_handle, value);
   }
+
+  /**
+   * Resets the simulated value to 0. Use this instead of Set(0) for resetting incremental sensor
+   * values like encoder counts or gyro accumulated angle to ensure correct behavior in a
+   * distributed system (e.g. WebSockets).
+   */
+  public void reset() {
+    SimDeviceJNI.resetSimValue(m_handle);
+  }
 }

hal/src/main/java/edu/wpi/first/hal/SimInt.java

@@ -32,4 +32,13 @@ public class SimInt extends SimValue {
   public void set(int value) {
     SimDeviceJNI.setSimValueInt(m_handle, value);
   }
+
+  /**
+   * Resets the simulated value to 0. Use this instead of Set(0) for resetting incremental sensor
+   * values like encoder counts or gyro accumulated angle to ensure correct behavior in a
+   * distributed system (e.g. WebSockets).
+   */
+  public void reset() {
+    SimDeviceJNI.resetSimValue(m_handle);
+  }
 }

hal/src/main/java/edu/wpi/first/hal/SimLong.java

@@ -32,4 +32,13 @@ public class SimLong extends SimValue {
   public void set(long value) {
     SimDeviceJNI.setSimValueLong(m_handle, value);
   }
+
+  /**
+   * Resets the simulated value to 0. Use this instead of Set(0) for resetting incremental sensor
+   * values like encoder counts or gyro accumulated angle to ensure correct behavior in a
+   * distributed system (e.g. WebSockets).
+   */
+  public void reset() {
+    SimDeviceJNI.resetSimValue(m_handle);
+  }
 }

hal/src/main/java/edu/wpi/first/hal/simulation/SimDeviceDataJNI.java

@@ -60,6 +60,19 @@ public class SimDeviceDataJNI extends JNIWrapper {
 
   public static native void cancelSimValueChangedCallback(int uid);
 
+  /**
+   * Register a callback for SimDeviceJNI.resetSimValue(). The callback is called with the old
+   * value.
+   *
+   * @param handle simulated value handle
+   * @param callback callback
+   * @param initialNotify ignored (present for consistency)
+   */
+  public static native int registerSimValueResetCallback(
+      int handle, SimValueCallback2 callback, boolean initialNotify);
+
+  public static native void cancelSimValueResetCallback(int uid);
+
   public static native int getSimValueHandle(int device, String name);
 
   public static class SimValueInfo {