/***************************************************************************** * * This file is part of Mapnik (c++ mapping toolkit) * * Copyright (C) 2007 Artem Pavlenko * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * *****************************************************************************/ //$Id$ #include <boost/optional/optional.hpp> #include <boost/python.hpp> // boost::optional<T> to/from converter from John Wiegley template <typename T, typename TfromPy> struct object_from_python { object_from_python() { boost::python::converter::registry::push_back (&TfromPy::convertible, &TfromPy::construct, boost::python::type_id<T>()); } }; template <typename T, typename TtoPy, typename TfromPy> struct register_python_conversion { register_python_conversion() { boost::python::to_python_converter<T, TtoPy>(); object_from_python<T, TfromPy>(); } }; template <typename T> struct python_optional : public boost::noncopyable { struct optional_to_python { static PyObject * convert(const boost::optional<T>& value) { return (value ? boost::python::to_python_value<T>()(*value) : boost::python::detail::none()); } }; struct optional_from_python { static void * convertible(PyObject * source) { using namespace boost::python::converter; if (source == Py_None) return source; const registration& converters(registered<T>::converters); if (implicit_rvalue_convertible_from_python(source, converters)) { rvalue_from_python_stage1_data data = rvalue_from_python_stage1(source, converters); return rvalue_from_python_stage2(source, data, converters); } return NULL; } static void construct(PyObject * source, boost::python::converter::rvalue_from_python_stage1_data * data) { using namespace boost::python::converter; void * const storage = ((rvalue_from_python_storage<T> *) data)->storage.bytes; if (data->convertible == source) // == None new (storage) boost::optional<T>(); // A Boost uninitialized value else new (storage) boost::optional<T>(*static_cast<T *>(data->convertible)); data->convertible = storage; } }; explicit python_optional() { register_python_conversion<boost::optional<T>, optional_to_python, optional_from_python>(); } };