mirror of
https://github.com/pybind/pybind11.git
synced 2024-11-11 08:03:55 +00:00
477 lines
17 KiB
C++
477 lines
17 KiB
C++
/*
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pybind/cast.h: Partial template specializations to cast between
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C++ and Python types
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Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
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All rights reserved. Use of this source code is governed by a
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BSD-style license that can be found in the LICENSE file.
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*/
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#pragma once
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#include <pybind/pytypes.h>
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#include <pybind/typeid.h>
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#include <array>
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NAMESPACE_BEGIN(pybind)
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NAMESPACE_BEGIN(detail)
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/// Generic type caster for objects stored on the heap
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template <typename type> class type_caster {
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public:
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typedef instance<type> instance_type;
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static std::string name() { return type_id<type>(); }
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type_caster() {
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auto const& registered_types = get_internals().registered_types;
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auto it = registered_types.find(type_id<type>());
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if (it != registered_types.end())
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typeinfo = &it->second;
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}
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bool load(PyObject *src, bool convert) {
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if (src == nullptr || typeinfo == nullptr)
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return false;
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if (PyType_IsSubtype(Py_TYPE(src), typeinfo->type)) {
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value = ((instance_type *) src)->value;
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return true;
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}
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if (convert) {
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for (auto &converter : typeinfo->implicit_conversions) {
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temp = object(converter(src, typeinfo->type), false);
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if (load(temp.ptr(), false))
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return true;
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}
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}
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return false;
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}
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static PyObject *cast(const type &src, return_value_policy policy, PyObject *parent) {
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if (policy == return_value_policy::automatic)
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policy = return_value_policy::copy;
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return cast(&src, policy, parent);
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}
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static PyObject *cast(const type *_src, return_value_policy policy, PyObject *parent) {
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type *src = const_cast<type *>(_src);
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if (src == nullptr) {
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Py_INCREF(Py_None);
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return Py_None;
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}
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// avoid an issue with internal references matching their parent's address
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bool dont_cache = policy == return_value_policy::reference_internal &&
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parent && ((instance<void> *) parent)->value == (void *) src;
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auto& internals = get_internals();
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auto it_instance = internals.registered_instances.find(src);
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if (it_instance != internals.registered_instances.end() && !dont_cache) {
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PyObject *inst = it_instance->second;
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Py_INCREF(inst);
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return inst;
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}
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auto it = internals.registered_types.find(type_id<type>());
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if (it == internals.registered_types.end()) {
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std::string msg = std::string("Unregistered type : ") + type_id<type>();
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PyErr_SetString(PyExc_TypeError, msg.c_str());
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return nullptr;
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}
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auto &type_info = it->second;
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instance_type *inst = (instance_type *) PyType_GenericAlloc(type_info.type, 0);
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inst->value = src;
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inst->owned = true;
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inst->parent = nullptr;
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if (policy == return_value_policy::automatic)
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policy = return_value_policy::take_ownership;
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handle_return_value_policy<type>(inst, policy, parent);
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PyObject *inst_pyobj = (PyObject *) inst;
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type_info.init_holder(inst_pyobj);
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if (!dont_cache)
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internals.registered_instances[inst->value] = inst_pyobj;
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return inst_pyobj;
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}
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template <class T, typename std::enable_if<std::is_copy_constructible<T>::value, int>::type = 0>
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static void handle_return_value_policy(instance<T> *inst, return_value_policy policy, PyObject *parent) {
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if (policy == return_value_policy::copy) {
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inst->value = new T(*(inst->value));
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} else if (policy == return_value_policy::reference) {
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inst->owned = false;
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} else if (policy == return_value_policy::reference_internal) {
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inst->owned = false;
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inst->parent = parent;
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Py_XINCREF(parent);
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}
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}
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template <class T, typename std::enable_if<!std::is_copy_constructible<T>::value, int>::type = 0>
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static void handle_return_value_policy(instance<T> *inst, return_value_policy policy, PyObject *parent) {
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if (policy == return_value_policy::copy) {
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throw cast_error("return_value_policy = copy, but the object is non-copyable!");
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} else if (policy == return_value_policy::reference) {
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inst->owned = false;
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} else if (policy == return_value_policy::reference_internal) {
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inst->owned = false;
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inst->parent = parent;
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Py_XINCREF(parent);
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}
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}
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operator type*() { return value; }
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operator type&() { return *value; }
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protected:
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type *value = nullptr;
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const type_info *typeinfo = nullptr;
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object temp;
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};
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#define PYBIND_TYPE_CASTER(type, py_name) \
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protected: \
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type value; \
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public: \
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static std::string name() { return py_name; } \
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static PyObject *cast(const type *src, return_value_policy policy, PyObject *parent) { \
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return cast(*src, policy, parent); \
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} \
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operator type*() { return &value; } \
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operator type&() { return value; } \
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#define PYBIND_TYPE_CASTER_NUMBER(type, py_type, from_type, to_pytype) \
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template <> class type_caster<type> { \
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public: \
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bool load(PyObject *src, bool) { \
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value = (type) from_type(src); \
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if (value == (type) -1 && PyErr_Occurred()) { \
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PyErr_Clear(); \
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return false; \
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} \
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return true; \
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} \
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static PyObject *cast(type src, return_value_policy /* policy */, PyObject * /* parent */) { \
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return to_pytype((py_type) src); \
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} \
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PYBIND_TYPE_CASTER(type, #type); \
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};
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PYBIND_TYPE_CASTER_NUMBER(int32_t, long, PyLong_AsLong, PyLong_FromLong)
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PYBIND_TYPE_CASTER_NUMBER(uint32_t, unsigned long, PyLong_AsUnsignedLong, PyLong_FromUnsignedLong)
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PYBIND_TYPE_CASTER_NUMBER(int64_t, PY_LONG_LONG, PyLong_AsLongLong, PyLong_FromLongLong)
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PYBIND_TYPE_CASTER_NUMBER(uint64_t, unsigned PY_LONG_LONG, PyLong_AsUnsignedLongLong, PyLong_FromUnsignedLongLong)
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#if defined(__APPLE__) // size_t/ssize_t are separate types on Mac OS X
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PYBIND_TYPE_CASTER_NUMBER(ssize_t, Py_ssize_t, PyLong_AsSsize_t, PyLong_FromSsize_t)
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PYBIND_TYPE_CASTER_NUMBER(size_t, size_t, PyLong_AsSize_t, PyLong_FromSize_t)
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#endif
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PYBIND_TYPE_CASTER_NUMBER(float, float, PyFloat_AsDouble, PyFloat_FromDouble)
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PYBIND_TYPE_CASTER_NUMBER(double, double, PyFloat_AsDouble, PyFloat_FromDouble)
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template <> class type_caster<void_type> {
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public:
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bool load(PyObject *, bool) { return true; }
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static PyObject *cast(void_type, return_value_policy /* policy */, PyObject * /* parent */) {
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Py_INCREF(Py_None);
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return Py_None;
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}
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PYBIND_TYPE_CASTER(void_type, "None");
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};
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template <> class type_caster<bool> {
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public:
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bool load(PyObject *src, bool) {
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if (src == Py_True) { value = true; return true; }
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else if (src == Py_False) { value = false; return true; }
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else return false;
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}
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static PyObject *cast(bool src, return_value_policy /* policy */, PyObject * /* parent */) {
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PyObject *result = src ? Py_True : Py_False;
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Py_INCREF(result);
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return result;
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}
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PYBIND_TYPE_CASTER(bool, "bool");
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};
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template <> class type_caster<std::string> {
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public:
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bool load(PyObject *src, bool) {
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const char *ptr = PyUnicode_AsUTF8(src);
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if (!ptr) { PyErr_Clear(); return false; }
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value = std::string(ptr);
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return true;
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}
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static PyObject *cast(const std::string &src, return_value_policy /* policy */, PyObject * /* parent */) {
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return PyUnicode_FromString(src.c_str());
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}
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PYBIND_TYPE_CASTER(std::string, "str");
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};
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#ifdef HAVE_WCHAR_H
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template <> class type_caster<std::wstring> {
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public:
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bool load(PyObject *src, bool) {
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const wchar_t *ptr = PyUnicode_AsWideCharString(src, nullptr);
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if (!ptr) { PyErr_Clear(); return false; }
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value = std::wstring(ptr);
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return true;
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}
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static PyObject *cast(const std::wstring &src, return_value_policy /* policy */, PyObject * /* parent */) {
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return PyUnicode_FromWideChar(src.c_str(), src.length());
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}
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PYBIND_TYPE_CASTER(std::wstring, "wstr");
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};
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#endif
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template <> class type_caster<char> {
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public:
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bool load(PyObject *src, bool) {
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char *ptr = PyUnicode_AsUTF8(src);
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if (!ptr) { PyErr_Clear(); return false; }
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value = ptr;
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return true;
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}
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static PyObject *cast(const char *src, return_value_policy /* policy */, PyObject * /* parent */) {
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return PyUnicode_FromString(src);
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}
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static PyObject *cast(char src, return_value_policy /* policy */, PyObject * /* parent */) {
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char str[2] = { src, '\0' };
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return PyUnicode_DecodeLatin1(str, 1, nullptr);
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}
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static std::string name() { return "str"; }
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operator char*() { return value; }
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operator char() { return *value; }
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protected:
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char *value;
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};
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template <typename T1, typename T2> class type_caster<std::pair<T1, T2>> {
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typedef std::pair<T1, T2> type;
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public:
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bool load(PyObject *src, bool convert) {
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if (!PyTuple_Check(src) || PyTuple_Size(src) != 2)
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return false;
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if (!first.load(PyTuple_GetItem(src, 0), convert))
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return false;
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return second.load(PyTuple_GetItem(src, 1), convert);
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}
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static PyObject *cast(const type &src, return_value_policy policy, PyObject *parent) {
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PyObject *o1 = type_caster<typename decay<T1>::type>::cast(src.first, policy, parent);
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PyObject *o2 = type_caster<typename decay<T2>::type>::cast(src.second, policy, parent);
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if (!o1 || !o2) {
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Py_XDECREF(o1);
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Py_XDECREF(o2);
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return nullptr;
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}
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PyObject *tuple = PyTuple_New(2);
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PyTuple_SetItem(tuple, 0, o1);
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PyTuple_SetItem(tuple, 1, o2);
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return tuple;
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}
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static std::string name() {
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return "(" + type_caster<T1>::name() + ", " + type_caster<T2>::name() + ")";
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}
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operator type() {
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return type(first, second);
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}
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protected:
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type_caster<typename decay<T1>::type> first;
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type_caster<typename decay<T2>::type> second;
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};
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template <typename... Tuple> class type_caster<std::tuple<Tuple...>> {
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typedef std::tuple<Tuple...> type;
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public:
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enum { size = sizeof...(Tuple) };
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bool load(PyObject *src, bool convert) {
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return load(src, convert, typename make_index_sequence<sizeof...(Tuple)>::type());
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}
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static PyObject *cast(const type &src, return_value_policy policy, PyObject *parent) {
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return cast(src, policy, parent, typename make_index_sequence<size>::type());
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}
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static std::string name(const char **keywords = nullptr, const char **values = nullptr) {
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std::array<std::string, size> names {{
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type_caster<typename decay<Tuple>::type>::name()...
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}};
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std::string result("(");
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int counter = 0;
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for (auto const &name : names) {
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if (keywords && keywords[counter]) {
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result += keywords[counter];
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result += " : ";
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}
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result += name;
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if (values && values[counter]) {
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result += " = ";
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result += values[counter];
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}
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if (++counter < size)
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result += ", ";
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}
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result += ")";
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return result;
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}
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template <typename ReturnValue, typename Func> typename std::enable_if<!std::is_void<ReturnValue>::value, ReturnValue>::type call(Func &&f) {
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return call<ReturnValue>(std::forward<Func>(f), typename make_index_sequence<sizeof...(Tuple)>::type());
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}
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template <typename ReturnValue, typename Func> typename std::enable_if<std::is_void<ReturnValue>::value, void_type>::type call(Func &&f) {
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call<ReturnValue>(std::forward<Func>(f), typename make_index_sequence<sizeof...(Tuple)>::type());
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return void_type();
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}
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operator type() {
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return cast(typename make_index_sequence<sizeof...(Tuple)>::type());
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}
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protected:
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template <typename ReturnValue, typename Func, size_t ... Index> ReturnValue call(Func &&f, index_sequence<Index...>) {
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return f((Tuple) std::get<Index>(value)...);
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}
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template <size_t ... Index> type cast(index_sequence<Index...>) {
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return type((Tuple) std::get<Index>(value)...);
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}
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template <size_t ... Indices> bool load(PyObject *src, bool convert, index_sequence<Indices...>) {
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if (!PyTuple_Check(src))
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return false;
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if (PyTuple_Size(src) != size)
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return false;
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std::array<bool, size> results {{
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(PyTuple_GET_ITEM(src, Indices) != nullptr ? std::get<Indices>(value).load(PyTuple_GET_ITEM(src, Indices), convert) : false)...
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}};
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(void) convert; /* avoid a warning when the tuple is empty */
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for (bool r : results)
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if (!r)
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return false;
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return true;
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}
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/* Implementation: Convert a C++ tuple into a Python tuple */
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template <size_t ... Indices> static PyObject *cast(const type &src, return_value_policy policy, PyObject *parent, index_sequence<Indices...>) {
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std::array<PyObject *, size> results {{
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type_caster<typename decay<Tuple>::type>::cast(std::get<Indices>(src), policy, parent)...
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}};
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bool success = true;
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for (auto result : results)
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if (result == nullptr)
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success = false;
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if (success) {
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PyObject *tuple = PyTuple_New(size);
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int counter = 0;
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for (auto result : results)
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PyTuple_SetItem(tuple, counter++, result);
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return tuple;
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} else {
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for (auto result : results) {
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Py_XDECREF(result);
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}
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return nullptr;
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}
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}
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protected:
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std::tuple<type_caster<typename decay<Tuple>::type>...> value;
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};
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/// Type caster for holder types like std::shared_ptr, etc.
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template <typename type, typename holder_type> class type_caster_holder : public type_caster<type> {
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public:
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typedef type_caster<type> parent;
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bool load(PyObject *src, bool convert) {
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if (!parent::load(src, convert))
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return false;
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holder = holder_type(parent::value);
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return true;
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}
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explicit operator type*() { return this->value; }
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explicit operator type&() { return *(this->value); }
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explicit operator holder_type&() { return holder; }
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explicit operator holder_type*() { return &holder; }
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protected:
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holder_type holder;
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};
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template <> class type_caster<handle> {
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public:
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bool load(PyObject *src) {
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value = handle(src);
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return true;
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}
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static PyObject *cast(const handle &src, return_value_policy /* policy */, PyObject * /* parent */) {
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src.inc_ref();
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return (PyObject *) src.ptr();
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}
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PYBIND_TYPE_CASTER(handle, "handle");
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};
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#define PYBIND_TYPE_CASTER_PYTYPE(name) \
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template <> class type_caster<name> { \
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public: \
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bool load(PyObject *src, bool) { value = name(src, true); return true; } \
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static PyObject *cast(const name &src, return_value_policy /* policy */, PyObject * /* parent */) { \
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src.inc_ref(); return (PyObject *) src.ptr(); \
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} \
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PYBIND_TYPE_CASTER(name, #name); \
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};
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PYBIND_TYPE_CASTER_PYTYPE(object) PYBIND_TYPE_CASTER_PYTYPE(buffer)
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PYBIND_TYPE_CASTER_PYTYPE(capsule) PYBIND_TYPE_CASTER_PYTYPE(dict)
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PYBIND_TYPE_CASTER_PYTYPE(float_) PYBIND_TYPE_CASTER_PYTYPE(int_)
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PYBIND_TYPE_CASTER_PYTYPE(list) PYBIND_TYPE_CASTER_PYTYPE(slice)
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PYBIND_TYPE_CASTER_PYTYPE(tuple) PYBIND_TYPE_CASTER_PYTYPE(function)
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NAMESPACE_END(detail)
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template <typename T> inline T cast(PyObject *object) {
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detail::type_caster<typename detail::decay<T>::type> conv;
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if (!conv.load(object, true))
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throw cast_error("Unable to cast Python object to C++ type");
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return conv;
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}
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template <typename T> inline object cast(const T &value, return_value_policy policy = return_value_policy::automatic, PyObject *parent = nullptr) {
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if (policy == return_value_policy::automatic)
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policy = std::is_pointer<T>::value ? return_value_policy::take_ownership : return_value_policy::copy;
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return object(detail::type_caster<typename detail::decay<T>::type>::cast(value, policy, parent), false);
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}
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template <typename T> inline T handle::cast() { return pybind::cast<T>(m_ptr); }
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template <typename... Args> inline object handle::call(Args&&... args_) {
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const size_t size = sizeof...(Args);
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std::array<PyObject *, size> args{
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{ detail::type_caster<typename detail::decay<Args>::type>::cast(
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std::forward<Args>(args_), return_value_policy::automatic, nullptr)... }
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};
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bool fail = false;
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for (auto result : args)
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if (result == nullptr)
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fail = true;
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if (fail) {
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for (auto result : args) {
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Py_XDECREF(result);
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}
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throw cast_error("handle::call(): unable to convert input arguments to Python objects");
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}
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PyObject *tuple = PyTuple_New(size);
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int counter = 0;
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for (auto result : args)
|
|
PyTuple_SetItem(tuple, counter++, result);
|
|
PyObject *result = PyObject_CallObject(m_ptr, tuple);
|
|
Py_DECREF(tuple);
|
|
return object(result, false);
|
|
}
|
|
|
|
NAMESPACE_END(pybind)
|