mirror of
https://github.com/python/cpython.git
synced 2024-12-05 15:54:17 +08:00
226a012d1c
Several built-in and standard library types now ensure that their internal result tuples are always tracked by the garbage collector: - collections.OrderedDict.items - dict.items - enumerate - functools.reduce - itertools.combinations - itertools.combinations_with_replacement - itertools.permutations - itertools.product - itertools.zip_longest - zip Previously, they could have become untracked by a prior garbage collection.
480 lines
15 KiB
C
480 lines
15 KiB
C
/* enumerate object */
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#include "Python.h"
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#include "pycore_long.h" // _PyLong_GetOne()
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#include "pycore_object.h" // _PyObject_GC_TRACK()
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#include "clinic/enumobject.c.h"
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/*[clinic input]
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class enumerate "enumobject *" "&PyEnum_Type"
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class reversed "reversedobject *" "&PyReversed_Type"
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[clinic start generated code]*/
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/*[clinic end generated code: output=da39a3ee5e6b4b0d input=d2dfdf1a88c88975]*/
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typedef struct {
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PyObject_HEAD
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Py_ssize_t en_index; /* current index of enumeration */
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PyObject* en_sit; /* secondary iterator of enumeration */
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PyObject* en_result; /* result tuple */
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PyObject* en_longindex; /* index for sequences >= PY_SSIZE_T_MAX */
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} enumobject;
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/*[clinic input]
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@classmethod
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enumerate.__new__ as enum_new
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iterable: object
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an object supporting iteration
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start: object = 0
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Return an enumerate object.
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The enumerate object yields pairs containing a count (from start, which
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defaults to zero) and a value yielded by the iterable argument.
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enumerate is useful for obtaining an indexed list:
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(0, seq[0]), (1, seq[1]), (2, seq[2]), ...
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[clinic start generated code]*/
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static PyObject *
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enum_new_impl(PyTypeObject *type, PyObject *iterable, PyObject *start)
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/*[clinic end generated code: output=e95e6e439f812c10 input=782e4911efcb8acf]*/
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{
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enumobject *en;
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en = (enumobject *)type->tp_alloc(type, 0);
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if (en == NULL)
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return NULL;
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if (start != NULL) {
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start = PyNumber_Index(start);
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if (start == NULL) {
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Py_DECREF(en);
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return NULL;
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}
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assert(PyLong_Check(start));
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en->en_index = PyLong_AsSsize_t(start);
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if (en->en_index == -1 && PyErr_Occurred()) {
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PyErr_Clear();
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en->en_index = PY_SSIZE_T_MAX;
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en->en_longindex = start;
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} else {
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en->en_longindex = NULL;
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Py_DECREF(start);
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}
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} else {
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en->en_index = 0;
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en->en_longindex = NULL;
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}
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en->en_sit = PyObject_GetIter(iterable);
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if (en->en_sit == NULL) {
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Py_DECREF(en);
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return NULL;
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}
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en->en_result = PyTuple_Pack(2, Py_None, Py_None);
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if (en->en_result == NULL) {
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Py_DECREF(en);
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return NULL;
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}
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return (PyObject *)en;
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}
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static void
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enum_dealloc(enumobject *en)
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{
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PyObject_GC_UnTrack(en);
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Py_XDECREF(en->en_sit);
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Py_XDECREF(en->en_result);
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Py_XDECREF(en->en_longindex);
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Py_TYPE(en)->tp_free(en);
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}
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static int
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enum_traverse(enumobject *en, visitproc visit, void *arg)
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{
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Py_VISIT(en->en_sit);
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Py_VISIT(en->en_result);
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Py_VISIT(en->en_longindex);
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return 0;
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}
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static PyObject *
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enum_next_long(enumobject *en, PyObject* next_item)
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{
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PyObject *result = en->en_result;
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PyObject *next_index;
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PyObject *stepped_up;
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PyObject *old_index;
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PyObject *old_item;
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if (en->en_longindex == NULL) {
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en->en_longindex = PyLong_FromSsize_t(PY_SSIZE_T_MAX);
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if (en->en_longindex == NULL) {
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Py_DECREF(next_item);
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return NULL;
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}
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}
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next_index = en->en_longindex;
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assert(next_index != NULL);
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stepped_up = PyNumber_Add(next_index, _PyLong_GetOne());
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if (stepped_up == NULL) {
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Py_DECREF(next_item);
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return NULL;
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}
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en->en_longindex = stepped_up;
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if (Py_REFCNT(result) == 1) {
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Py_INCREF(result);
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old_index = PyTuple_GET_ITEM(result, 0);
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old_item = PyTuple_GET_ITEM(result, 1);
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PyTuple_SET_ITEM(result, 0, next_index);
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PyTuple_SET_ITEM(result, 1, next_item);
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Py_DECREF(old_index);
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Py_DECREF(old_item);
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// bpo-42536: The GC may have untracked this result tuple. Since we're
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// recycling it, make sure it's tracked again:
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if (!_PyObject_GC_IS_TRACKED(result)) {
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_PyObject_GC_TRACK(result);
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}
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return result;
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}
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result = PyTuple_New(2);
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if (result == NULL) {
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Py_DECREF(next_index);
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Py_DECREF(next_item);
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return NULL;
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}
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PyTuple_SET_ITEM(result, 0, next_index);
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PyTuple_SET_ITEM(result, 1, next_item);
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return result;
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}
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static PyObject *
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enum_next(enumobject *en)
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{
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PyObject *next_index;
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PyObject *next_item;
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PyObject *result = en->en_result;
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PyObject *it = en->en_sit;
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PyObject *old_index;
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PyObject *old_item;
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next_item = (*Py_TYPE(it)->tp_iternext)(it);
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if (next_item == NULL)
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return NULL;
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if (en->en_index == PY_SSIZE_T_MAX)
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return enum_next_long(en, next_item);
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next_index = PyLong_FromSsize_t(en->en_index);
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if (next_index == NULL) {
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Py_DECREF(next_item);
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return NULL;
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}
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en->en_index++;
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if (Py_REFCNT(result) == 1) {
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Py_INCREF(result);
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old_index = PyTuple_GET_ITEM(result, 0);
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old_item = PyTuple_GET_ITEM(result, 1);
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PyTuple_SET_ITEM(result, 0, next_index);
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PyTuple_SET_ITEM(result, 1, next_item);
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Py_DECREF(old_index);
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Py_DECREF(old_item);
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// bpo-42536: The GC may have untracked this result tuple. Since we're
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// recycling it, make sure it's tracked again:
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if (!_PyObject_GC_IS_TRACKED(result)) {
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_PyObject_GC_TRACK(result);
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}
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return result;
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}
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result = PyTuple_New(2);
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if (result == NULL) {
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Py_DECREF(next_index);
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Py_DECREF(next_item);
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return NULL;
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}
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PyTuple_SET_ITEM(result, 0, next_index);
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PyTuple_SET_ITEM(result, 1, next_item);
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return result;
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}
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static PyObject *
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enum_reduce(enumobject *en, PyObject *Py_UNUSED(ignored))
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{
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if (en->en_longindex != NULL)
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return Py_BuildValue("O(OO)", Py_TYPE(en), en->en_sit, en->en_longindex);
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else
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return Py_BuildValue("O(On)", Py_TYPE(en), en->en_sit, en->en_index);
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}
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PyDoc_STRVAR(reduce_doc, "Return state information for pickling.");
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static PyMethodDef enum_methods[] = {
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{"__reduce__", (PyCFunction)enum_reduce, METH_NOARGS, reduce_doc},
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{"__class_getitem__", (PyCFunction)Py_GenericAlias,
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METH_O|METH_CLASS, PyDoc_STR("See PEP 585")},
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{NULL, NULL} /* sentinel */
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};
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PyTypeObject PyEnum_Type = {
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PyVarObject_HEAD_INIT(&PyType_Type, 0)
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"enumerate", /* tp_name */
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sizeof(enumobject), /* tp_basicsize */
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0, /* tp_itemsize */
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/* methods */
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(destructor)enum_dealloc, /* tp_dealloc */
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0, /* tp_vectorcall_offset */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_as_async */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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PyObject_GenericGetAttr, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
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Py_TPFLAGS_BASETYPE, /* tp_flags */
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enum_new__doc__, /* tp_doc */
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(traverseproc)enum_traverse, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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0, /* tp_weaklistoffset */
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PyObject_SelfIter, /* tp_iter */
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(iternextfunc)enum_next, /* tp_iternext */
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enum_methods, /* tp_methods */
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0, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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0, /* tp_descr_get */
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0, /* tp_descr_set */
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0, /* tp_dictoffset */
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0, /* tp_init */
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PyType_GenericAlloc, /* tp_alloc */
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enum_new, /* tp_new */
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PyObject_GC_Del, /* tp_free */
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};
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/* Reversed Object ***************************************************************/
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typedef struct {
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PyObject_HEAD
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Py_ssize_t index;
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PyObject* seq;
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} reversedobject;
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/*[clinic input]
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@classmethod
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reversed.__new__ as reversed_new
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sequence as seq: object
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/
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Return a reverse iterator over the values of the given sequence.
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[clinic start generated code]*/
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static PyObject *
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reversed_new_impl(PyTypeObject *type, PyObject *seq)
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/*[clinic end generated code: output=f7854cc1df26f570 input=aeb720361e5e3f1d]*/
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{
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Py_ssize_t n;
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PyObject *reversed_meth;
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reversedobject *ro;
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_Py_IDENTIFIER(__reversed__);
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reversed_meth = _PyObject_LookupSpecial(seq, &PyId___reversed__);
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if (reversed_meth == Py_None) {
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Py_DECREF(reversed_meth);
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PyErr_Format(PyExc_TypeError,
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"'%.200s' object is not reversible",
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Py_TYPE(seq)->tp_name);
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return NULL;
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}
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if (reversed_meth != NULL) {
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PyObject *res = _PyObject_CallNoArg(reversed_meth);
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Py_DECREF(reversed_meth);
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return res;
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}
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else if (PyErr_Occurred())
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return NULL;
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if (!PySequence_Check(seq)) {
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PyErr_Format(PyExc_TypeError,
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"'%.200s' object is not reversible",
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Py_TYPE(seq)->tp_name);
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return NULL;
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}
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n = PySequence_Size(seq);
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if (n == -1)
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return NULL;
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ro = (reversedobject *)type->tp_alloc(type, 0);
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if (ro == NULL)
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return NULL;
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ro->index = n-1;
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Py_INCREF(seq);
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ro->seq = seq;
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return (PyObject *)ro;
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}
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static PyObject *
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reversed_vectorcall(PyObject *type, PyObject * const*args,
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size_t nargsf, PyObject *kwnames)
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{
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assert(PyType_Check(type));
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if (!_PyArg_NoKwnames("reversed", kwnames)) {
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return NULL;
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}
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Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
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if (!_PyArg_CheckPositional("reversed", nargs, 1, 1)) {
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return NULL;
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}
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return reversed_new_impl((PyTypeObject *)type, args[0]);
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}
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static void
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reversed_dealloc(reversedobject *ro)
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{
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PyObject_GC_UnTrack(ro);
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Py_XDECREF(ro->seq);
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Py_TYPE(ro)->tp_free(ro);
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}
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static int
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reversed_traverse(reversedobject *ro, visitproc visit, void *arg)
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{
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Py_VISIT(ro->seq);
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return 0;
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}
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static PyObject *
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reversed_next(reversedobject *ro)
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{
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PyObject *item;
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Py_ssize_t index = ro->index;
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if (index >= 0) {
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item = PySequence_GetItem(ro->seq, index);
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if (item != NULL) {
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ro->index--;
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return item;
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}
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if (PyErr_ExceptionMatches(PyExc_IndexError) ||
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PyErr_ExceptionMatches(PyExc_StopIteration))
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PyErr_Clear();
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}
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ro->index = -1;
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Py_CLEAR(ro->seq);
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return NULL;
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}
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static PyObject *
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reversed_len(reversedobject *ro, PyObject *Py_UNUSED(ignored))
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{
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Py_ssize_t position, seqsize;
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if (ro->seq == NULL)
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return PyLong_FromLong(0);
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seqsize = PySequence_Size(ro->seq);
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if (seqsize == -1)
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return NULL;
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position = ro->index + 1;
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return PyLong_FromSsize_t((seqsize < position) ? 0 : position);
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}
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PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
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static PyObject *
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reversed_reduce(reversedobject *ro, PyObject *Py_UNUSED(ignored))
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{
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if (ro->seq)
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return Py_BuildValue("O(O)n", Py_TYPE(ro), ro->seq, ro->index);
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else
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return Py_BuildValue("O(())", Py_TYPE(ro));
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}
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static PyObject *
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reversed_setstate(reversedobject *ro, PyObject *state)
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{
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Py_ssize_t index = PyLong_AsSsize_t(state);
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if (index == -1 && PyErr_Occurred())
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return NULL;
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if (ro->seq != 0) {
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Py_ssize_t n = PySequence_Size(ro->seq);
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if (n < 0)
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return NULL;
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if (index < -1)
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index = -1;
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else if (index > n-1)
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index = n-1;
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ro->index = index;
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}
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Py_RETURN_NONE;
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}
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PyDoc_STRVAR(setstate_doc, "Set state information for unpickling.");
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static PyMethodDef reversediter_methods[] = {
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{"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc},
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{"__reduce__", (PyCFunction)reversed_reduce, METH_NOARGS, reduce_doc},
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{"__setstate__", (PyCFunction)reversed_setstate, METH_O, setstate_doc},
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{NULL, NULL} /* sentinel */
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};
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PyTypeObject PyReversed_Type = {
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PyVarObject_HEAD_INIT(&PyType_Type, 0)
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"reversed", /* tp_name */
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sizeof(reversedobject), /* tp_basicsize */
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0, /* tp_itemsize */
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/* methods */
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(destructor)reversed_dealloc, /* tp_dealloc */
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0, /* tp_vectorcall_offset */
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0, /* tp_getattr */
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0, /* tp_setattr */
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0, /* tp_as_async */
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0, /* tp_repr */
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0, /* tp_as_number */
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0, /* tp_as_sequence */
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0, /* tp_as_mapping */
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0, /* tp_hash */
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0, /* tp_call */
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0, /* tp_str */
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PyObject_GenericGetAttr, /* tp_getattro */
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0, /* tp_setattro */
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0, /* tp_as_buffer */
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Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
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Py_TPFLAGS_BASETYPE, /* tp_flags */
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reversed_new__doc__, /* tp_doc */
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(traverseproc)reversed_traverse,/* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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0, /* tp_weaklistoffset */
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PyObject_SelfIter, /* tp_iter */
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(iternextfunc)reversed_next, /* tp_iternext */
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reversediter_methods, /* tp_methods */
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0, /* tp_members */
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0, /* tp_getset */
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0, /* tp_base */
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0, /* tp_dict */
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0, /* tp_descr_get */
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0, /* tp_descr_set */
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0, /* tp_dictoffset */
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0, /* tp_init */
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PyType_GenericAlloc, /* tp_alloc */
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reversed_new, /* tp_new */
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PyObject_GC_Del, /* tp_free */
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.tp_vectorcall = (vectorcallfunc)reversed_vectorcall,
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};
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