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--- youtube:python-mixing-003x2 [2024/02/28 18:26] – 削除 - 外部編集 (不明な日付) 127.0.0.1
+++ youtube:python-mixing-003x2 [2024/02/28 18:26] (現在) – ↷ toybox:python-mixing-003x2 から youtube:python-mixing-003x2 へページを移動しました。 freemikan
@@ 行 1: / 行 1: @@
+====== CでPythonのクラスを作る ======
+作成日: 2023-08-04 (金)
+[[https://youtu.be/kYp_yQfunhU|第3回 Python/C APIに触れてみる (2)]]
+===== ソースコード =====
+==== setup.py ====
+<file python>
+from setuptools import setup, Extension
+setup(
+    name="pointlib",
+    ext_modules=[
+        Extension("pointlibmodule", ["pointlibmodule.c"])
+    ]
+)
+</file>
+==== pointlibmodule.c ====
+<file c>
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <structmember.h>
+// clang-format off
+typedef struct {
+    PyObject_HEAD
+    double x;
+    double y;
+} PointObject;
+// clang-format on
+static int Point_init(PointObject *self, PyObject *args) {
+    double x, y;
+    if (!PyArg_ParseTuple(args, "dd", &x, &y)) {
+        return -1;
+    }
+    self->x = x;
+    self->y = y;
+    return 0;
+}
+static PyObject *Point_to_s(PointObject *self, PyObject *Py_UNUSED(ignored)) {
+    char buf[1024];
+    snprintf(buf, 1024, "(%lf,%lf)", self->x, self->y);
+    return PyUnicode_FromFormat("%s", buf);
+}
+static PyMemberDef Point_members[] = {
+    {"x", T_DOUBLE, offsetof(PointObject, x), 0, "x coord"},
+    {"y", T_DOUBLE, offsetof(PointObject, y), 0, "y coord"},
+    {NULL}};
+static PyMethodDef Point_methods[] = {
+    {"to_s", (PyCFunction)Point_to_s, METH_NOARGS, "Return formated string."},
+    {NULL, NULL, 0, NULL}};
+static PyTypeObject PointType = {
+    PyVarObject_HEAD_INIT(NULL, 0).tp_name = "pointlib.Point",
+    .tp_doc = PyDoc_STR("Point object"),
+    .tp_basicsize = sizeof(PointObject),
+    .tp_itemsize = 0,
+    .tp_flags = Py_TPFLAGS_DEFAULT,
+    .tp_new = PyType_GenericNew,
+    .tp_init = (initproc)Point_init,
+    .tp_members = Point_members,
+    .tp_methods = Point_methods,
+};
+static PyObject *pointlib_distance(PyObject *self, PyObject *args) {
+    PyObject *pt1, *pt2;
+    if (!PyArg_ParseTuple(args, "OO", &pt1, &pt2)) {
+        return NULL;
+    }
+    PyObject *x1_obj = PyObject_GetAttrString(pt1, "x");
+    PyObject *y1_obj = PyObject_GetAttrString(pt1, "y");
+    PyObject *x2_obj = PyObject_GetAttrString(pt2, "x");
+    PyObject *y2_obj = PyObject_GetAttrString(pt2, "y");
+    if (x1_obj == NULL || y1_obj == NULL || x2_obj == NULL || y2_obj == NULL) {
+        Py_XDECREF(x1_obj);
+        Py_XDECREF(y1_obj);
+        Py_XDECREF(x2_obj);
+        Py_XDECREF(y2_obj);
+        return NULL;
+    }
+    double x1 = PyFloat_AsDouble(x1_obj);
+    double y1 = PyFloat_AsDouble(y1_obj);
+    double x2 = PyFloat_AsDouble(x2_obj);
+    double y2 = PyFloat_AsDouble(y2_obj);
+    double dx = x2 - x1;
+    double dy = y2 - y1;
+    double dist = sqrt(dx * dx + dy * dy);
+    Py_DECREF(x1_obj);
+    Py_DECREF(y1_obj);
+    Py_DECREF(x2_obj);
+    Py_DECREF(y2_obj);
+    return PyFloat_FromDouble(dist);
+}
+static PyMethodDef pointlib_methods[] = {
+    {"distance", pointlib_distance, METH_VARARGS,
+     PyDoc_STR("Distance between two points.")},
+    {NULL, NULL, 0, NULL}};
+static PyModuleDef pointlib_module = {
+    PyModuleDef_HEAD_INIT,
+    .m_name = "pointlib",
+    .m_doc = PyDoc_STR("Example module creating custom type."),
+    .m_size = -1,
+    .m_methods = pointlib_methods,
+};
+PyMODINIT_FUNC PyInit_pointlib(void) {
+    if (PyType_Ready(&PointType) < 0) {
+        return NULL;
+    }
+    PyObject *module = PyModule_Create(&pointlib_module);
+    if (module == NULL) {
+        return NULL;
+    }
+    Py_INCREF(&PointType);
+    if (PyModule_AddObject(module, "Point", (PyObject *)&PointType) < 0) {
+        Py_DECREF(&PointType);
+        Py_DECREF(module);
+        return NULL;
+    }
+    return module;
+}
+</file>