Minimize passing STL objects past dynamic library boundaries to improve stability of IfcOpenShell-Python

src/ifcwrap/IfcPython.i

@@ -41,13 +41,46 @@
 	#include "../ifcparse/IfcLateBoundEntity.h"
 %}
 
+// The following typemaps are an alternative for the read-only std::vector
+// implementations provided by SWIG, as passing STL objects across dynamic
+// library boundaries can be problematic.
+%typemap(out) std::pair<const float*, unsigned> {
+	$result = PyTuple_New($1.second);
+	for (unsigned i = 0; i < $1.second; ++i) {
+		PyTuple_SetItem($result, i, PyFloat_FromDouble($1.first[i]));
+	}
+}
+%typemap(out) std::pair<const double*, unsigned> {
+	$result = PyTuple_New($1.second);
+	for (unsigned i = 0; i < $1.second; ++i) {
+		PyTuple_SetItem($result, i, PyFloat_FromDouble($1.first[i]));
+	}
+}
+%typemap(out) std::pair<const int*, unsigned> {
+	$result = PyTuple_New($1.second);
+	for (unsigned i = 0; i < $1.second; ++i) {
+		PyTuple_SetItem($result, i, PyLong_FromLong($1.first[i]));
+	}
+}
+%typemap(out) std::pair<const std::string*, unsigned> {
+	$result = PyTuple_New($1.second);
+	for (unsigned i = 0; i < $1.second; ++i) {
+		PyTuple_SetItem($result, i, PyUnicode_FromString($1.first[i]->c_str()));
+	}
+}
+%typemap(out) std::pair<const IfcGeom::Material*, unsigned> {
+	$result = PyTuple_New($1.second);
+	for (unsigned i = 0; i < $1.second; ++i) {
+		PyTuple_SetItem($result, i, SWIG_NewPointerObj(SWIG_as_voidptr(&$1.first[i]), SWIGTYPE_p_IfcGeom__Material, 0));
+	}
+}
+%typemap(out) std::vector<unsigned> {
+	$result = PyTuple_New($1.size());
+	unsigned i = 0;
+	for (std::vector<unsigned>::const_iterator it = $1.begin(); it != $1.end(); ++it) {
+		PyTuple_SetItem($result, i++, PyLong_FromLong(*it));
+	}
+}
+
 %include "IfcGeomWrapper.i"
 %include "IfcParseWrapper.i"
-
-namespace std {
-	%template(int_vector) vector<int>;
-	%template(float_vector) vector<float>;
-	%template(double_vector) vector<double>;
-	%template(string_vector) vector<std::string>;
-	%template(material_vector) vector<IfcGeom::Material>;
-};