mirror of
https://github.com/python/cpython
synced 2024-09-05 08:17:45 +00:00
440 lines
11 KiB
C
440 lines
11 KiB
C
/* Use this file as a template to start implementing a module that
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also declares object types. All occurrences of 'Xxo' should be changed
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to something reasonable for your objects. After that, all other
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occurrences of 'xx' should be changed to something reasonable for your
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module. If your module is named foo your source file should be named
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foo.c or foomodule.c.
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You will probably want to delete all references to 'x_attr' and add
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your own types of attributes instead. Maybe you want to name your
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local variables other than 'self'. If your object type is needed in
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other files, you'll have to create a file "foobarobject.h"; see
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floatobject.h for an example.
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This module roughly corresponds to::
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class Xxo:
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"""A class that explicitly stores attributes in an internal dict"""
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def __init__(self):
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# In the C class, "_x_attr" is not accessible from Python code
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self._x_attr = {}
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self._x_exports = 0
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def __getattr__(self, name):
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return self._x_attr[name]
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def __setattr__(self, name, value):
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self._x_attr[name] = value
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def __delattr__(self, name):
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del self._x_attr[name]
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@property
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def x_exports(self):
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"""Return the number of times an internal buffer is exported."""
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# Each Xxo instance has a 10-byte buffer that can be
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# accessed via the buffer interface (e.g. `memoryview`).
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return self._x_exports
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def demo(o, /):
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if isinstance(o, str):
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return o
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elif isinstance(o, Xxo):
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return o
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else:
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raise Error('argument must be str or Xxo')
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class Error(Exception):
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"""Exception raised by the xxlimited module"""
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def foo(i: int, j: int, /):
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"""Return the sum of i and j."""
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# Unlike this pseudocode, the C function will *only* work with
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# integers and perform C long int arithmetic
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return i + j
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def new():
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return Xxo()
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def Str(str):
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# A trivial subclass of a built-in type
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pass
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*/
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#define Py_LIMITED_API 0x030b0000
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#include "Python.h"
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#include <string.h>
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#define BUFSIZE 10
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// Module state
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typedef struct {
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PyObject *Xxo_Type; // Xxo class
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PyObject *Error_Type; // Error class
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} xx_state;
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/* Xxo objects */
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// Instance state
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typedef struct {
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PyObject_HEAD
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PyObject *x_attr; /* Attributes dictionary */
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char x_buffer[BUFSIZE]; /* buffer for Py_buffer */
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Py_ssize_t x_exports; /* how many buffer are exported */
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} XxoObject;
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// XXX: no good way to do this yet
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// #define XxoObject_Check(v) Py_IS_TYPE(v, Xxo_Type)
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static XxoObject *
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newXxoObject(PyObject *module)
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{
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xx_state *state = PyModule_GetState(module);
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if (state == NULL) {
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return NULL;
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}
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XxoObject *self;
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self = PyObject_GC_New(XxoObject, (PyTypeObject*)state->Xxo_Type);
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if (self == NULL) {
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return NULL;
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}
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self->x_attr = NULL;
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memset(self->x_buffer, 0, BUFSIZE);
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self->x_exports = 0;
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return self;
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}
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/* Xxo finalization */
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static int
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Xxo_traverse(PyObject *self_obj, visitproc visit, void *arg)
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{
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// Visit the type
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Py_VISIT(Py_TYPE(self_obj));
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// Visit the attribute dict
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XxoObject *self = (XxoObject *)self_obj;
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Py_VISIT(self->x_attr);
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return 0;
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}
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static int
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Xxo_clear(XxoObject *self)
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{
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Py_CLEAR(self->x_attr);
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return 0;
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}
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static void
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Xxo_finalize(PyObject *self_obj)
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{
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XxoObject *self = (XxoObject *)self_obj;
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Py_CLEAR(self->x_attr);
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}
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static void
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Xxo_dealloc(PyObject *self)
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{
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PyObject_GC_UnTrack(self);
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Xxo_finalize(self);
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PyTypeObject *tp = Py_TYPE(self);
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freefunc free = PyType_GetSlot(tp, Py_tp_free);
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free(self);
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Py_DECREF(tp);
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}
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/* Xxo attribute handling */
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static PyObject *
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Xxo_getattro(XxoObject *self, PyObject *name)
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{
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if (self->x_attr != NULL) {
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PyObject *v = PyDict_GetItemWithError(self->x_attr, name);
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if (v != NULL) {
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Py_INCREF(v);
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return v;
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}
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else if (PyErr_Occurred()) {
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return NULL;
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}
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}
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return PyObject_GenericGetAttr((PyObject *)self, name);
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}
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static int
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Xxo_setattro(XxoObject *self, PyObject *name, PyObject *v)
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{
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if (self->x_attr == NULL) {
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// prepare the attribute dict
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self->x_attr = PyDict_New();
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if (self->x_attr == NULL) {
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return -1;
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}
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}
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if (v == NULL) {
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// delete an attribute
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int rv = PyDict_DelItem(self->x_attr, name);
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if (rv < 0 && PyErr_ExceptionMatches(PyExc_KeyError)) {
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PyErr_SetString(PyExc_AttributeError,
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"delete non-existing Xxo attribute");
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return -1;
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}
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return rv;
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}
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else {
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// set an attribute
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return PyDict_SetItem(self->x_attr, name, v);
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}
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}
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/* Xxo methods */
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static PyObject *
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Xxo_demo(XxoObject *self, PyTypeObject *defining_class,
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PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
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{
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if (kwnames != NULL && PyObject_Length(kwnames)) {
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PyErr_SetString(PyExc_TypeError, "demo() takes no keyword arguments");
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return NULL;
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}
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if (nargs != 1) {
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PyErr_SetString(PyExc_TypeError, "demo() takes exactly 1 argument");
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return NULL;
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}
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PyObject *o = args[0];
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/* Test if the argument is "str" */
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if (PyUnicode_Check(o)) {
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Py_INCREF(o);
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return o;
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}
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/* test if the argument is of the Xxo class */
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if (PyObject_TypeCheck(o, defining_class)) {
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Py_INCREF(o);
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return o;
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}
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Py_INCREF(Py_None);
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return Py_None;
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}
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static PyMethodDef Xxo_methods[] = {
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{"demo", _PyCFunction_CAST(Xxo_demo),
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METH_METHOD | METH_FASTCALL | METH_KEYWORDS, PyDoc_STR("demo(o) -> o")},
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{NULL, NULL} /* sentinel */
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};
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/* Xxo buffer interface */
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static int
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Xxo_getbuffer(XxoObject *self, Py_buffer *view, int flags)
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{
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int res = PyBuffer_FillInfo(view, (PyObject*)self,
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(void *)self->x_buffer, BUFSIZE,
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0, flags);
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if (res == 0) {
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self->x_exports++;
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}
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return res;
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}
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static void
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Xxo_releasebuffer(XxoObject *self, Py_buffer *view)
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{
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self->x_exports--;
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}
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static PyObject *
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Xxo_get_x_exports(XxoObject *self, void *c)
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{
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return PyLong_FromSsize_t(self->x_exports);
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}
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/* Xxo type definition */
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PyDoc_STRVAR(Xxo_doc,
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"A class that explicitly stores attributes in an internal dict");
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static PyGetSetDef Xxo_getsetlist[] = {
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{"x_exports", (getter) Xxo_get_x_exports, NULL, NULL},
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{NULL},
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};
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static PyType_Slot Xxo_Type_slots[] = {
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{Py_tp_doc, (char *)Xxo_doc},
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{Py_tp_traverse, Xxo_traverse},
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{Py_tp_clear, Xxo_clear},
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{Py_tp_finalize, Xxo_finalize},
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{Py_tp_dealloc, Xxo_dealloc},
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{Py_tp_getattro, Xxo_getattro},
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{Py_tp_setattro, Xxo_setattro},
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{Py_tp_methods, Xxo_methods},
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{Py_bf_getbuffer, Xxo_getbuffer},
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{Py_bf_releasebuffer, Xxo_releasebuffer},
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{Py_tp_getset, Xxo_getsetlist},
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{0, 0}, /* sentinel */
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};
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static PyType_Spec Xxo_Type_spec = {
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.name = "xxlimited.Xxo",
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.basicsize = sizeof(XxoObject),
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.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
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.slots = Xxo_Type_slots,
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};
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/* Str type definition*/
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static PyType_Slot Str_Type_slots[] = {
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{0, 0}, /* sentinel */
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};
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static PyType_Spec Str_Type_spec = {
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.name = "xxlimited.Str",
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.basicsize = 0,
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.flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
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.slots = Str_Type_slots,
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};
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/* Function of two integers returning integer (with C "long int" arithmetic) */
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PyDoc_STRVAR(xx_foo_doc,
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"foo(i,j)\n\
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\n\
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Return the sum of i and j.");
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static PyObject *
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xx_foo(PyObject *module, PyObject *args)
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{
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long i, j;
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long res;
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if (!PyArg_ParseTuple(args, "ll:foo", &i, &j))
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return NULL;
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res = i+j; /* XXX Do something here */
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return PyLong_FromLong(res);
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}
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/* Function of no arguments returning new Xxo object */
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static PyObject *
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xx_new(PyObject *module, PyObject *Py_UNUSED(unused))
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{
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XxoObject *rv;
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rv = newXxoObject(module);
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if (rv == NULL)
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return NULL;
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return (PyObject *)rv;
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}
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/* List of functions defined in the module */
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static PyMethodDef xx_methods[] = {
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{"foo", xx_foo, METH_VARARGS,
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xx_foo_doc},
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{"new", xx_new, METH_NOARGS,
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PyDoc_STR("new() -> new Xx object")},
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{NULL, NULL} /* sentinel */
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};
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/* The module itself */
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PyDoc_STRVAR(module_doc,
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"This is a template module just for instruction.");
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static int
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xx_modexec(PyObject *m)
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{
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xx_state *state = PyModule_GetState(m);
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state->Error_Type = PyErr_NewException("xxlimited.Error", NULL, NULL);
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if (state->Error_Type == NULL) {
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return -1;
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}
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if (PyModule_AddType(m, (PyTypeObject*)state->Error_Type) < 0) {
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return -1;
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}
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state->Xxo_Type = PyType_FromModuleAndSpec(m, &Xxo_Type_spec, NULL);
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if (state->Xxo_Type == NULL) {
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return -1;
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}
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if (PyModule_AddType(m, (PyTypeObject*)state->Xxo_Type) < 0) {
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return -1;
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}
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// Add the Str type. It is not needed from C code, so it is only
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// added to the module dict.
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// It does not inherit from "object" (PyObject_Type), but from "str"
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// (PyUnincode_Type).
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PyObject *Str_Type = PyType_FromModuleAndSpec(
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m, &Str_Type_spec, (PyObject *)&PyUnicode_Type);
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if (Str_Type == NULL) {
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return -1;
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}
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if (PyModule_AddType(m, (PyTypeObject*)Str_Type) < 0) {
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return -1;
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}
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Py_DECREF(Str_Type);
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return 0;
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}
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static PyModuleDef_Slot xx_slots[] = {
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{Py_mod_exec, xx_modexec},
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{0, NULL}
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};
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static int
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xx_traverse(PyObject *module, visitproc visit, void *arg)
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{
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xx_state *state = PyModule_GetState(module);
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Py_VISIT(state->Xxo_Type);
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Py_VISIT(state->Error_Type);
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return 0;
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}
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static int
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xx_clear(PyObject *module)
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{
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xx_state *state = PyModule_GetState(module);
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Py_CLEAR(state->Xxo_Type);
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Py_CLEAR(state->Error_Type);
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return 0;
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}
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static struct PyModuleDef xxmodule = {
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PyModuleDef_HEAD_INIT,
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.m_name = "xxlimited",
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.m_doc = module_doc,
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.m_size = sizeof(xx_state),
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.m_methods = xx_methods,
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.m_slots = xx_slots,
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.m_traverse = xx_traverse,
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.m_clear = xx_clear,
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/* m_free is not necessary here: xx_clear clears all references,
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* and the module state is deallocated along with the module.
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*/
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};
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/* Export function for the module (*must* be called PyInit_xx) */
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PyMODINIT_FUNC
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PyInit_xxlimited(void)
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{
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return PyModuleDef_Init(&xxmodule);
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}
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