ref: 90143609212ed4500409a64d26f6b12d097b13ed
dir: /sys/src/cmd/python/Objects/enumobject.c/
/* enumerate object */
#include "Python.h"
typedef struct {
PyObject_HEAD
long en_index; /* current index of enumeration */
PyObject* en_sit; /* secondary iterator of enumeration */
PyObject* en_result; /* result tuple */
} enumobject;
static PyObject *
enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
enumobject *en;
PyObject *seq = NULL;
static char *kwlist[] = {"sequence", 0};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:enumerate", kwlist,
&seq))
return NULL;
en = (enumobject *)type->tp_alloc(type, 0);
if (en == NULL)
return NULL;
en->en_index = 0;
en->en_sit = PyObject_GetIter(seq);
if (en->en_sit == NULL) {
Py_DECREF(en);
return NULL;
}
en->en_result = PyTuple_Pack(2, Py_None, Py_None);
if (en->en_result == NULL) {
Py_DECREF(en);
return NULL;
}
return (PyObject *)en;
}
static void
enum_dealloc(enumobject *en)
{
PyObject_GC_UnTrack(en);
Py_XDECREF(en->en_sit);
Py_XDECREF(en->en_result);
en->ob_type->tp_free(en);
}
static int
enum_traverse(enumobject *en, visitproc visit, void *arg)
{
Py_VISIT(en->en_sit);
Py_VISIT(en->en_result);
return 0;
}
static PyObject *
enum_next(enumobject *en)
{
PyObject *next_index;
PyObject *next_item;
PyObject *result = en->en_result;
PyObject *it = en->en_sit;
if (en->en_index == LONG_MAX) {
PyErr_SetString(PyExc_OverflowError,
"enumerate() is limited to LONG_MAX items");
return NULL;
}
next_item = (*it->ob_type->tp_iternext)(it);
if (next_item == NULL)
return NULL;
next_index = PyInt_FromLong(en->en_index);
if (next_index == NULL) {
Py_DECREF(next_item);
return NULL;
}
en->en_index++;
if (result->ob_refcnt == 1) {
Py_INCREF(result);
Py_DECREF(PyTuple_GET_ITEM(result, 0));
Py_DECREF(PyTuple_GET_ITEM(result, 1));
} else {
result = PyTuple_New(2);
if (result == NULL) {
Py_DECREF(next_index);
Py_DECREF(next_item);
return NULL;
}
}
PyTuple_SET_ITEM(result, 0, next_index);
PyTuple_SET_ITEM(result, 1, next_item);
return result;
}
PyDoc_STRVAR(enum_doc,
"enumerate(iterable) -> iterator for index, value of iterable\n"
"\n"
"Return an enumerate object. iterable must be an other object that supports\n"
"iteration. The enumerate object yields pairs containing a count (from\n"
"zero) and a value yielded by the iterable argument. enumerate is useful\n"
"for obtaining an indexed list: (0, seq[0]), (1, seq[1]), (2, seq[2]), ...");
PyTypeObject PyEnum_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
"enumerate", /* tp_name */
sizeof(enumobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)enum_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE, /* tp_flags */
enum_doc, /* tp_doc */
(traverseproc)enum_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)enum_next, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
enum_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};
/* Reversed Object ***************************************************************/
typedef struct {
PyObject_HEAD
Py_ssize_t index;
PyObject* seq;
} reversedobject;
static PyObject *
reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
Py_ssize_t n;
PyObject *seq;
reversedobject *ro;
if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq))
return NULL;
if (PyObject_HasAttrString(seq, "__reversed__"))
return PyObject_CallMethod(seq, "__reversed__", NULL);
if (!PySequence_Check(seq)) {
PyErr_SetString(PyExc_TypeError,
"argument to reversed() must be a sequence");
return NULL;
}
n = PySequence_Size(seq);
if (n == -1)
return NULL;
ro = (reversedobject *)type->tp_alloc(type, 0);
if (ro == NULL)
return NULL;
ro->index = n-1;
Py_INCREF(seq);
ro->seq = seq;
return (PyObject *)ro;
}
static void
reversed_dealloc(reversedobject *ro)
{
PyObject_GC_UnTrack(ro);
Py_XDECREF(ro->seq);
ro->ob_type->tp_free(ro);
}
static int
reversed_traverse(reversedobject *ro, visitproc visit, void *arg)
{
Py_VISIT(ro->seq);
return 0;
}
static PyObject *
reversed_next(reversedobject *ro)
{
PyObject *item;
Py_ssize_t index = ro->index;
if (index >= 0) {
item = PySequence_GetItem(ro->seq, index);
if (item != NULL) {
ro->index--;
return item;
}
if (PyErr_ExceptionMatches(PyExc_IndexError) ||
PyErr_ExceptionMatches(PyExc_StopIteration))
PyErr_Clear();
}
ro->index = -1;
Py_CLEAR(ro->seq);
return NULL;
}
PyDoc_STRVAR(reversed_doc,
"reversed(sequence) -> reverse iterator over values of the sequence\n"
"\n"
"Return a reverse iterator");
static PyObject *
reversed_len(reversedobject *ro)
{
Py_ssize_t position, seqsize;
if (ro->seq == NULL)
return PyInt_FromLong(0);
seqsize = PySequence_Size(ro->seq);
if (seqsize == -1)
return NULL;
position = ro->index + 1;
return PyInt_FromSsize_t((seqsize < position) ? 0 : position);
}
PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
static PyMethodDef reversediter_methods[] = {
{"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyReversed_Type = {
PyObject_HEAD_INIT(&PyType_Type)
0, /* ob_size */
"reversed", /* tp_name */
sizeof(reversedobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)reversed_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE, /* tp_flags */
reversed_doc, /* tp_doc */
(traverseproc)reversed_traverse,/* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)reversed_next, /* tp_iternext */
reversediter_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
reversed_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};