[wpilib] Implement Trajectory.equals() (#2517)

wpilibc/src/main/native/cpp/trajectory/Trajectory.cpp

@@ -151,3 +151,11 @@ void frc::from_json(const wpi::json& json, Trajectory::State& state) {
       units::meters_per_second_squared_t{json.at("acceleration").get<double>()};
   state.curvature = units::curvature_t{json.at("curvature").get<double>()};
 }
+
+bool Trajectory::operator==(const Trajectory& other) const {
+  return m_states == other.States();
+}
+
+bool Trajectory::operator!=(const Trajectory& other) const {
+  return !operator==(other);
+}

wpilibc/src/main/native/include/frc/trajectory/Trajectory.h

@@ -127,6 +127,22 @@ class Trajectory {
    */
   Pose2d InitialPose() const { return Sample(0_s).pose; }
 
+  /**
+   * Checks equality between this Trajectory and another object.
+   *
+   * @param other The other object.
+   * @return Whether the two objects are equal.
+   */
+  bool operator==(const Trajectory& other) const;
+
+  /**
+   * Checks inequality between this Trajectory and another object.
+   *
+   * @param other The other object.
+   * @return Whether the two objects are inequal.
+   */
+  bool operator!=(const Trajectory& other) const;
+
  private:
   std::vector<State> m_states;
   units::second_t m_totalTime = 0_s;

wpilibj/src/main/java/edu/wpi/first/wpilibj/trajectory/Trajectory.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2019-2020 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.                                                               */
@@ -328,4 +328,14 @@ public class Trajectory {
     String stateList = m_states.stream().map(State::toString).collect(Collectors.joining(", \n"));
     return String.format("Trajectory - Seconds: %.2f, States:\n%s", m_totalTimeSeconds, stateList);
   }
+
+  @Override
+  public int hashCode() {
+    return m_states.hashCode();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    return obj instanceof Trajectory && m_states.equals(((Trajectory) obj).getStates());
+  }
 }