Part: Add method to split B-spline curve

Add the method GeomBSplineCurve::split() to split a B-Spline curve into
two curves.

src/Mod/Part/App/BSplineCurvePyImp.cpp

@@ -327,6 +327,26 @@ PyObject* BSplineCurvePy::segment(PyObject* args)
     }
 }
 
+PyObject* BSplineCurvePy::split(PyObject* args) const
+{
+    double u {};
+    double tolerance = 0.0;
+    if (!PyArg_ParseTuple(args, "d|d", &u, &tolerance)) {
+        return nullptr;
+    }
+    try {
+        auto curves = getGeomBSplineCurvePtr()->split(u, tolerance);
+        Py::Tuple tuple(2);
+        tuple.setItem(0, Py::asObject(std::get<0>(curves)->getPyObject()));
+        tuple.setItem(1, Py::asObject(std::get<1>(curves)->getPyObject()));
+        return Py::new_reference_to(tuple);
+    }
+    catch (Standard_Failure& e) {
+        PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
+        return nullptr;
+    }
+}
+
 PyObject* BSplineCurvePy::setKnot(PyObject* args)
 {
     int Index, M = -1;

src/Mod/Part/App/Geometry.cpp

@@ -1711,6 +1711,18 @@ bool GeomBSplineCurve::join(const Handle(Geom_BoundedCurve) & other)
     return true;
 }
 
+std::tuple<GeomBSplineCurvePtr, GeomBSplineCurvePtr> GeomBSplineCurve::split(double u, double tol) const
+{
+    Handle(Geom_BSplineCurve) curveL
+        = GeomConvert::SplitBSplineCurve(myCurve, myCurve->FirstParameter(), u, tol, true);
+    Handle(Geom_BSplineCurve) curveR
+        = GeomConvert::SplitBSplineCurve(myCurve, u, myCurve->LastParameter(), tol, true);
+    return std::make_tuple(
+        std::make_shared<GeomBSplineCurve>(curveL),
+        std::make_shared<GeomBSplineCurve>(curveR)
+    );
+}
+
 void GeomBSplineCurve::interpolate(const std::vector<gp_Pnt>& p, Standard_Boolean periodic)
 {
     if (p.size() < 2) {

src/Mod/Part/App/Geometry.h

@@ -311,6 +311,7 @@ private:
     Handle(Geom_BezierCurve) myCurve;
 };
 
+using GeomBSplineCurvePtr = std::shared_ptr<GeomBSplineCurve>;
 class PartExport GeomBSplineCurve: public GeomBoundedCurve
 {
     TYPESYSTEM_HEADER_WITH_OVERRIDE();
@@ -377,6 +378,7 @@ public:
     void setPeriodic() const;
     bool isRational() const;
     bool join(const Handle(Geom_BoundedCurve) &);
+    std::tuple<GeomBSplineCurvePtr, GeomBSplineCurvePtr> split(double u, double tol) const;
     void makeC1Continuous(double, double);
     std::list<Geometry*> toBiArcs(double tolerance) const;