[Python] piecewise::curve_at_index do not return reference anymore, update Python bindings

include/curves/piecewise_curve.h

@@ -212,9 +212,9 @@ struct piecewise_curve : public curve_abc<Time, Numeric, Safe, Point, Point_deri
 
   std::size_t num_curves() const { return curves_.size(); }
 
-  const curve_ptr_t& curve_at_time(const time_t t) const { return curves_[find_interval(t)]; }
+  curve_ptr_t curve_at_time(const time_t t) const { return curves_[find_interval(t)]; }
 
-  const curve_ptr_t& curve_at_index(const std::size_t idx) const {
+  curve_ptr_t curve_at_index(const std::size_t idx) const {
     if (Safe && idx >= num_curves()) {
       throw std::length_error(
           "curve_at_index: requested index greater than number of curves in piecewise_curve instance");

python/curves/curves_python.cpp

@@ -239,6 +239,14 @@ static piecewise_t discretPointToPolynomialC2(const pointX_list_t& points, const
       points_list, points_derivative_list, points_second_derivative_list, time_points_list);
 }
 
+curve_abc_t* getCurveAtIndex(piecewise_t& self, const std::size_t idx){
+  return self.curve_at_index(idx).get();
+}
+
+curve_abc_t* getCurveAtTime(piecewise_t& self, const time_t t){
+  return self.curve_at_time(t).get();
+}
+
 void addFinalPointC0(piecewise_t& self, const pointX_t& end, const real time) {
   if (self.num_curves() == 0)
     throw std::runtime_error(
@@ -741,8 +749,8 @@ BOOST_PYTHON_MODULE(curves) {
       .def("convert_piecewise_curve_to_cubic_hermite",
            &piecewise_t::convert_piecewise_curve_to_cubic_hermite<cubic_hermite_spline_t>,
            "Convert a piecewise curve to to a piecewise cubic hermite spline")
-      .def("curve_at_index", &piecewise_t::curve_at_index, return_value_policy<copy_const_reference>())
-      .def("curve_at_time", &piecewise_t::curve_at_time, return_value_policy<copy_const_reference>())
+      .def("curve_at_index", &getCurveAtIndex, return_internal_reference<>())
+      .def("curve_at_time", &getCurveAtTime, return_internal_reference<>())
       .def("num_curves", &piecewise_t::num_curves)
       .def("saveAsText", &piecewise_t::saveAsText<piecewise_t>, bp::args("filename"),
            "Saves *this inside a text file.")
@@ -769,8 +777,8 @@ BOOST_PYTHON_MODULE(curves) {
            "where T_{min} is equal toT_{max} of the actual piecewise curve.")
       .def("is_continuous", &piecewise_bezier_t::is_continuous, "Check if the curve is continuous at the given order.",
            args("self,order"))
-      .def("curve_at_index", &piecewise_bezier_t::curve_at_index, return_value_policy<copy_const_reference>())
-      .def("curve_at_time", &piecewise_bezier_t::curve_at_time, return_value_policy<copy_const_reference>())
+      .def("curve_at_index", &getCurveAtIndex, return_internal_reference<>())
+      .def("curve_at_time", &getCurveAtTime, return_internal_reference<>())
       .def("num_curves", &piecewise_bezier_t::num_curves)
       .def("saveAsText", &piecewise_bezier_t::saveAsText<piecewise_bezier_t>, bp::args("filename"),
            "Saves *this inside a text file.")
@@ -797,8 +805,8 @@ BOOST_PYTHON_MODULE(curves) {
            "where T_{min} is equal toT_{max} of the actual piecewise curve.")
       .def("is_continuous", &piecewise_linear_bezier_t::is_continuous,
            "Check if the curve is continuous at the given order.", args("self,order"))
-      .def("curve_at_index", &piecewise_linear_bezier_t::curve_at_index, return_value_policy<copy_const_reference>())
-      .def("curve_at_time", &piecewise_linear_bezier_t::curve_at_time, return_value_policy<copy_const_reference>())
+      .def("curve_at_index", &getCurveAtIndex, return_internal_reference<>())
+      .def("curve_at_time", &getCurveAtTime, return_internal_reference<>())
       .def("num_curves", &piecewise_linear_bezier_t::num_curves)
       .def("saveAsText", &piecewise_linear_bezier_t::saveAsText<piecewise_linear_bezier_t>, bp::args("filename"),
            "Saves *this inside a text file.")
@@ -825,8 +833,8 @@ BOOST_PYTHON_MODULE(curves) {
            args("self,curve"))
       .def("is_continuous", &piecewise_SE3_t::is_continuous, "Check if the curve is continuous at the given order.",
            args("self,order"))
-      .def("curve_at_index", &piecewise_SE3_t::curve_at_index, return_value_policy<copy_const_reference>())
-      .def("curve_at_time", &piecewise_SE3_t::curve_at_time, return_value_policy<copy_const_reference>())
+      .def("curve_at_index", &getCurveAtIndex, return_internal_reference<>())
+      .def("curve_at_time", &getCurveAtTime, return_internal_reference<>())
       .def("num_curves", &piecewise_SE3_t::num_curves)
       .def("append", &addFinalTransform,
            "Append a new linear SE3 curve at the end of the piecewise curve, defined between self.max() "