map.hpp

#ifndef __eigenpy_map_hpp__
#define __eigenpy_map_hpp__

#include "eigenpy/pickle-vector.hpp"
#include "eigenpy/registration.hpp"
#include "eigenpy/utils/empty-visitor.hpp"

#include <boost/python/suite/indexing/map_indexing_suite.hpp>
#include <boost/python/stl_iterator.hpp>
#include <boost/python/to_python_converter.hpp>

namespace eigenpy {

template <typename Container>
struct overload_base_get_item_for_map
 : public boost::python::def_visitor<
 overload_base_get_item_for_map<Container>> {
 typedef typename Container::value_type value_type;
 typedef typename Container::value_type::second_type data_type;
 typedef typename Container::key_type key_type;
 typedef typename Container::key_type index_type;

 template <class Class>
 void visit(Class& cl) const {
 cl.def("__getitem__", &base_get_item);
 }

 private:
 static boost::python::object base_get_item(
 boost::python::back_reference<Container&> container, PyObject* i_) {
 index_type idx = convert_index(container.get(), i_);
 typename Container::iterator i = container.get().find(idx);
 if (i == container.get().end()) {
 PyErr_SetString(PyExc_KeyError, "Invalid key");
 boost::python::throw_error_already_set();
 }

 typename boost::python::to_python_indirect<
 data_type&, boost::python::detail::make_reference_holder>
 convert;
 return boost::python::object(boost::python::handle<>(convert(i->second)));
 }

 static index_type convert_index(Container& /*container*/, PyObject* i_) {
 boost::python::extract<key_type const&> i(i_);
 if (i.check()) {
 return i();
 } else {
 boost::python::extract<key_type> i(i_);
 if (i.check()) return i();
 }

 PyErr_SetString(PyExc_TypeError, "Invalid index type");
 boost::python::throw_error_already_set();
 return index_type();
 }
};

// The following snippet of code has been taken from the header
// https://github.com/loco-3d/crocoddyl/blob/v2.1.0/bindings/python/crocoddyl/utils/map-converter.hpp
// The Crocoddyl library is written by Carlos Mastalli, Nicolas Mansard and
// Rohan Budhiraja.

namespace bp = boost::python;

template <typename Container>
struct PickleMap : public PickleVector<Container> {
 static void setstate(bp::object op, bp::tuple tup) {
 Container& o = bp::extract<Container&>(op)();
 bp::stl_input_iterator<typename Container::value_type> begin(tup[0]), end;
 o.insert(begin, end);
 }
};

template <typename Container>
struct dict_to_map {
 static void register_converter() {
 bp::converter::registry::push_back(&dict_to_map::convertible,
 &dict_to_map::construct,
 bp::type_id<Container>());
 }

 static void* convertible(PyObject* object) {
 // Check if it is a list
 if (!PyObject_GetIter(object)) return 0;
 return object;
 }

 static void construct(PyObject* object,
 bp::converter::rvalue_from_python_stage1_data* data) {
 // convert the PyObject pointed to by `object` to a bp::dict
 bp::handle<> handle(bp::borrowed(object)); // "smart ptr"
 bp::dict dict(handle);

 // get a pointer to memory into which we construct the map
 // this is provided by the Python runtime
 typedef bp::converter::rvalue_from_python_storage<Container> storage_type;
 void* storage = reinterpret_cast<storage_type*>(data)->storage.bytes;

 // placement-new allocate the result
 new (storage) Container();

 // iterate over the dictionary `dict`, fill up the map `map`
 Container& map(*(static_cast<Container*>(storage)));
 bp::list keys(dict.keys());
 int keycount(static_cast<int>(bp::len(keys)));
 for (int i = 0; i < keycount; ++i) {
 // get the key
 bp::object keyobj(keys[i]);
 bp::extract<typename Container::key_type> keyproxy(keyobj);
 if (!keyproxy.check()) {
 PyErr_SetString(PyExc_KeyError, "Bad key type");
 bp::throw_error_already_set();
 }
 typename Container::key_type key = keyproxy();

 // get the corresponding value
 bp::object valobj(dict[keyobj]);
 bp::extract<typename Container::mapped_type> valproxy(valobj);
 if (!valproxy.check()) {
 PyErr_SetString(PyExc_ValueError, "Bad value type");
 bp::throw_error_already_set();
 }
 typename Container::mapped_type val = valproxy();
 map.emplace(key, val);
 }

 // remember the location for later
 data->convertible = storage;
 }

 static bp::dict todict(Container& self) {
 bp::dict dict;
 typename Container::const_iterator it;
 for (it = self.begin(); it != self.end(); ++it) {
 dict.setdefault(it->first, it->second);
 }
 return dict;
 }
};

template <class Container, bool NoProxy>
struct emplace_set_derived_policies
 : bp::map_indexing_suite<Container, NoProxy,
 emplace_set_derived_policies<Container, NoProxy>> {
 typedef typename Container::key_type index_type;
 typedef typename Container::value_type::second_type data_type;
 typedef typename Container::value_type value_type;
 using DerivedPolicies =
 bp::detail::final_map_derived_policies<Container, NoProxy>;

 template <class Class>
 static void extension_def(Class& cl) {
 // Wrap the map's element (value_type)
 std::string elem_name = "map_indexing_suite_";
 bp::object class_name(cl.attr("__name__"));
 bp::extract<std::string> class_name_extractor(class_name);
 elem_name += class_name_extractor();
 elem_name += "_entry";
 namespace mpl = boost::mpl;

 typedef typename mpl::if_<
 mpl::and_<boost::is_class<data_type>, mpl::bool_<!NoProxy>>,
 bp::return_internal_reference<>, bp::default_call_policies>::type
 get_data_return_policy;

 bp::class_<value_type>(elem_name.c_str(), bp::no_init)
 .def("__repr__", &DerivedPolicies::print_elem)
 .def("data", &DerivedPolicies::get_data, get_data_return_policy())
 .def("key", &DerivedPolicies::get_key);
 }

 static void set_item(Container& container, index_type i, data_type const& v) {
 container.emplace(i, v);
 }
};

template <class Container, bool NoProxy = false>
struct GenericMapVisitor
 : public emplace_set_derived_policies<Container, NoProxy>,
 public dict_to_map<Container> {
 typedef dict_to_map<Container> FromPythonDictConverter;

 template <typename DerivedVisitor>
 static void expose(const std::string& class_name,
 const std::string& doc_string,
 const bp::def_visitor<DerivedVisitor>& visitor) {
 namespace bp = bp;

 if (!register_symbolic_link_to_registered_type<Container>()) {
 bp::class_<Container>(class_name.c_str(), doc_string.c_str())
 .def(GenericMapVisitor())
 .def("todict", &FromPythonDictConverter::todict, bp::arg("self"),
 "Returns the map type as a Python dictionary.")
 .def_pickle(PickleMap<Container>())
 .def(visitor);
 // Register conversion
 FromPythonDictConverter::register_converter();
 }
 }

 static void expose(const std::string& class_name,
 const std::string& doc_string = "") {
 expose(class_name, doc_string, EmptyPythonVisitor());
 }

 template <typename DerivedVisitor>
 static void expose(const std::string& class_name,
 const bp::def_visitor<DerivedVisitor>& visitor) {
 expose(class_name, "", visitor);
 }
};

} // namespace eigenpy

#endif // ifndef __eigenpy_map_hpp__