[wpimath] Add remaining struct and protobuf implementations (#5953)

wpimath/src/main/native/cpp/spline/struct/CubicHermiteSplineStruct.cpp

@@ -0,0 +1,31 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "frc/spline/struct/CubicHermiteSplineStruct.h"
+
+namespace {
+constexpr size_t kXInitialOff = 0;
+constexpr size_t kXFinalOff = kXInitialOff + 2 * 8;
+constexpr size_t kYInitialOff = kXFinalOff + 2 * 8;
+constexpr size_t kYFinalOff = kYInitialOff + 2 * 8;
+}  // namespace
+
+frc::CubicHermiteSpline wpi::Struct<frc::CubicHermiteSpline>::Unpack(
+    std::span<const uint8_t> data) {
+  return frc::CubicHermiteSpline{
+      wpi::UnpackStructArray<double, kXInitialOff, 2>(data),
+      wpi::UnpackStructArray<double, kXFinalOff, 2>(data),
+      wpi::UnpackStructArray<double, kYInitialOff, 2>(data),
+      wpi::UnpackStructArray<double, kYFinalOff, 2>(data)};
+}
+
+void wpi::Struct<frc::CubicHermiteSpline>::Pack(
+    std::span<uint8_t> data, const frc::CubicHermiteSpline& value) {
+  wpi::PackStructArray<kXInitialOff, 2>(data,
+                                        value.GetInitialControlVector().x);
+  wpi::PackStructArray<kXFinalOff, 2>(data, value.GetFinalControlVector().x);
+  wpi::PackStructArray<kYInitialOff, 2>(data,
+                                        value.GetInitialControlVector().y);
+  wpi::PackStructArray<kYFinalOff, 2>(data, value.GetFinalControlVector().y);
+}