7 Py_ssize_t en_index; /* current index of enumeration */
8 PyObject* en_sit; /* secondary iterator of enumeration */
9 PyObject* en_result; /* result tuple */
10 PyObject* en_longindex; /* index for sequences >= PY_SSIZE_T_MAX */
14 enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
18 PyObject *start = NULL;
19 static char *kwlist[] = {"sequence", "start", 0};
21 if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:enumerate", kwlist,
25 en = (enumobject *)type->tp_alloc(type, 0);
29 start = PyNumber_Index(start);
34 assert(PyInt_Check(start) || PyLong_Check(start));
35 en->en_index = PyInt_AsSsize_t(start);
36 if (en->en_index == -1 && PyErr_Occurred()) {
38 en->en_index = PY_SSIZE_T_MAX;
39 en->en_longindex = start;
41 en->en_longindex = NULL;
46 en->en_longindex = NULL;
48 en->en_sit = PyObject_GetIter(seq);
49 if (en->en_sit == NULL) {
53 en->en_result = PyTuple_Pack(2, Py_None, Py_None);
54 if (en->en_result == NULL) {
58 return (PyObject *)en;
62 enum_dealloc(enumobject *en)
64 PyObject_GC_UnTrack(en);
65 Py_XDECREF(en->en_sit);
66 Py_XDECREF(en->en_result);
67 Py_XDECREF(en->en_longindex);
68 Py_TYPE(en)->tp_free(en);
72 enum_traverse(enumobject *en, visitproc visit, void *arg)
75 Py_VISIT(en->en_result);
76 Py_VISIT(en->en_longindex);
81 enum_next_long(enumobject *en, PyObject* next_item)
83 static PyObject *one = NULL;
84 PyObject *result = en->en_result;
88 if (en->en_longindex == NULL) {
89 en->en_longindex = PyInt_FromSsize_t(PY_SSIZE_T_MAX);
90 if (en->en_longindex == NULL)
94 one = PyInt_FromLong(1);
98 next_index = en->en_longindex;
99 assert(next_index != NULL);
100 stepped_up = PyNumber_Add(next_index, one);
101 if (stepped_up == NULL)
103 en->en_longindex = stepped_up;
105 if (result->ob_refcnt == 1) {
107 Py_DECREF(PyTuple_GET_ITEM(result, 0));
108 Py_DECREF(PyTuple_GET_ITEM(result, 1));
110 result = PyTuple_New(2);
111 if (result == NULL) {
112 Py_DECREF(next_index);
113 Py_DECREF(next_item);
117 PyTuple_SET_ITEM(result, 0, next_index);
118 PyTuple_SET_ITEM(result, 1, next_item);
123 enum_next(enumobject *en)
125 PyObject *next_index;
127 PyObject *result = en->en_result;
128 PyObject *it = en->en_sit;
130 next_item = (*Py_TYPE(it)->tp_iternext)(it);
131 if (next_item == NULL)
134 if (en->en_index == PY_SSIZE_T_MAX)
135 return enum_next_long(en, next_item);
137 next_index = PyInt_FromSsize_t(en->en_index);
138 if (next_index == NULL) {
139 Py_DECREF(next_item);
144 if (result->ob_refcnt == 1) {
146 Py_DECREF(PyTuple_GET_ITEM(result, 0));
147 Py_DECREF(PyTuple_GET_ITEM(result, 1));
149 result = PyTuple_New(2);
150 if (result == NULL) {
151 Py_DECREF(next_index);
152 Py_DECREF(next_item);
156 PyTuple_SET_ITEM(result, 0, next_index);
157 PyTuple_SET_ITEM(result, 1, next_item);
161 PyDoc_STRVAR(enum_doc,
162 "enumerate(iterable) -> iterator for index, value of iterable\n"
164 "Return an enumerate object. iterable must be another object that supports\n"
165 "iteration. The enumerate object yields pairs containing a count (from\n"
166 "zero) and a value yielded by the iterable argument. enumerate is useful\n"
167 "for obtaining an indexed list: (0, seq[0]), (1, seq[1]), (2, seq[2]), ...");
169 PyTypeObject PyEnum_Type = {
170 PyVarObject_HEAD_INIT(&PyType_Type, 0)
171 "enumerate", /* tp_name */
172 sizeof(enumobject), /* tp_basicsize */
175 (destructor)enum_dealloc, /* tp_dealloc */
181 0, /* tp_as_number */
182 0, /* tp_as_sequence */
183 0, /* tp_as_mapping */
187 PyObject_GenericGetAttr, /* tp_getattro */
189 0, /* tp_as_buffer */
190 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
191 Py_TPFLAGS_BASETYPE, /* tp_flags */
192 enum_doc, /* tp_doc */
193 (traverseproc)enum_traverse, /* tp_traverse */
195 0, /* tp_richcompare */
196 0, /* tp_weaklistoffset */
197 PyObject_SelfIter, /* tp_iter */
198 (iternextfunc)enum_next, /* tp_iternext */
204 0, /* tp_descr_get */
205 0, /* tp_descr_set */
206 0, /* tp_dictoffset */
208 PyType_GenericAlloc, /* tp_alloc */
209 enum_new, /* tp_new */
210 PyObject_GC_Del, /* tp_free */
213 /* Reversed Object ***************************************************************/
222 reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
228 if (type == &PyReversed_Type && !_PyArg_NoKeywords("reversed()", kwds))
231 if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq) )
234 if (PyObject_HasAttrString(seq, "__reversed__"))
235 return PyObject_CallMethod(seq, "__reversed__", NULL);
237 if (!PySequence_Check(seq)) {
238 PyErr_SetString(PyExc_TypeError,
239 "argument to reversed() must be a sequence");
243 n = PySequence_Size(seq);
247 ro = (reversedobject *)type->tp_alloc(type, 0);
254 return (PyObject *)ro;
258 reversed_dealloc(reversedobject *ro)
260 PyObject_GC_UnTrack(ro);
262 Py_TYPE(ro)->tp_free(ro);
266 reversed_traverse(reversedobject *ro, visitproc visit, void *arg)
273 reversed_next(reversedobject *ro)
276 Py_ssize_t index = ro->index;
279 item = PySequence_GetItem(ro->seq, index);
284 if (PyErr_ExceptionMatches(PyExc_IndexError) ||
285 PyErr_ExceptionMatches(PyExc_StopIteration))
293 PyDoc_STRVAR(reversed_doc,
294 "reversed(sequence) -> reverse iterator over values of the sequence\n"
296 "Return a reverse iterator");
299 reversed_len(reversedobject *ro)
301 Py_ssize_t position, seqsize;
304 return PyInt_FromLong(0);
305 seqsize = PySequence_Size(ro->seq);
308 position = ro->index + 1;
309 return PyInt_FromSsize_t((seqsize < position) ? 0 : position);
312 PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
314 static PyMethodDef reversediter_methods[] = {
315 {"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc},
316 {NULL, NULL} /* sentinel */
319 PyTypeObject PyReversed_Type = {
320 PyVarObject_HEAD_INIT(&PyType_Type, 0)
321 "reversed", /* tp_name */
322 sizeof(reversedobject), /* tp_basicsize */
325 (destructor)reversed_dealloc, /* tp_dealloc */
331 0, /* tp_as_number */
332 0, /* tp_as_sequence */
333 0, /* tp_as_mapping */
337 PyObject_GenericGetAttr, /* tp_getattro */
339 0, /* tp_as_buffer */
340 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
341 Py_TPFLAGS_BASETYPE, /* tp_flags */
342 reversed_doc, /* tp_doc */
343 (traverseproc)reversed_traverse,/* tp_traverse */
345 0, /* tp_richcompare */
346 0, /* tp_weaklistoffset */
347 PyObject_SelfIter, /* tp_iter */
348 (iternextfunc)reversed_next, /* tp_iternext */
349 reversediter_methods, /* tp_methods */
354 0, /* tp_descr_get */
355 0, /* tp_descr_set */
356 0, /* tp_dictoffset */
358 PyType_GenericAlloc, /* tp_alloc */
359 reversed_new, /* tp_new */
360 PyObject_GC_Del, /* tp_free */