source: vendor/python/2.5/Objects/enumobject.c@ 3225

Last change on this file since 3225 was 3225, checked in by bird, 19 years ago

Python 2.5
File size: 8.3 KB
Line 
1/* enumerate object */
2
3#include "Python.h"
4
5typedef struct {
6 PyObject_HEAD
7 long en_index; /* current index of enumeration */
8 PyObject* en_sit; /* secondary iterator of enumeration */
9 PyObject* en_result; /* result tuple */
10} enumobject;
11
12static PyObject *
13enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
14{
15 enumobject *en;
16 PyObject *seq = NULL;
17 static char *kwlist[] = {"sequence", 0};
18
19 if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:enumerate", kwlist,
20 &seq))
21 return NULL;
22
23 en = (enumobject *)type->tp_alloc(type, 0);
24 if (en == NULL)
25 return NULL;
26 en->en_index = 0;
27 en->en_sit = PyObject_GetIter(seq);
28 if (en->en_sit == NULL) {
29 Py_DECREF(en);
30 return NULL;
31 }
32 en->en_result = PyTuple_Pack(2, Py_None, Py_None);
33 if (en->en_result == NULL) {
34 Py_DECREF(en);
35 return NULL;
36 }
37 return (PyObject *)en;
38}
39
40static void
41enum_dealloc(enumobject *en)
42{
43 PyObject_GC_UnTrack(en);
44 Py_XDECREF(en->en_sit);
45 Py_XDECREF(en->en_result);
46 en->ob_type->tp_free(en);
47}
48
49static int
50enum_traverse(enumobject *en, visitproc visit, void *arg)
51{
52 Py_VISIT(en->en_sit);
53 Py_VISIT(en->en_result);
54 return 0;
55}
56
57static PyObject *
58enum_next(enumobject *en)
59{
60 PyObject *next_index;
61 PyObject *next_item;
62 PyObject *result = en->en_result;
63 PyObject *it = en->en_sit;
64
65 next_item = (*it->ob_type->tp_iternext)(it);
66 if (next_item == NULL)
67 return NULL;
68
69 next_index = PyInt_FromLong(en->en_index);
70 if (next_index == NULL) {
71 Py_DECREF(next_item);
72 return NULL;
73 }
74 en->en_index++;
75
76 if (result->ob_refcnt == 1) {
77 Py_INCREF(result);
78 Py_DECREF(PyTuple_GET_ITEM(result, 0));
79 Py_DECREF(PyTuple_GET_ITEM(result, 1));
80 } else {
81 result = PyTuple_New(2);
82 if (result == NULL) {
83 Py_DECREF(next_index);
84 Py_DECREF(next_item);
85 return NULL;
86 }
87 }
88 PyTuple_SET_ITEM(result, 0, next_index);
89 PyTuple_SET_ITEM(result, 1, next_item);
90 return result;
91}
92
93PyDoc_STRVAR(enum_doc,
94"enumerate(iterable) -> iterator for index, value of iterable\n"
95"\n"
96"Return an enumerate object. iterable must be an other object that supports\n"
97"iteration. The enumerate object yields pairs containing a count (from\n"
98"zero) and a value yielded by the iterable argument. enumerate is useful\n"
99"for obtaining an indexed list: (0, seq[0]), (1, seq[1]), (2, seq[2]), ...");
100
101PyTypeObject PyEnum_Type = {
102 PyObject_HEAD_INIT(&PyType_Type)
103 0, /* ob_size */
104 "enumerate", /* tp_name */
105 sizeof(enumobject), /* tp_basicsize */
106 0, /* tp_itemsize */
107 /* methods */
108 (destructor)enum_dealloc, /* tp_dealloc */
109 0, /* tp_print */
110 0, /* tp_getattr */
111 0, /* tp_setattr */
112 0, /* tp_compare */
113 0, /* tp_repr */
114 0, /* tp_as_number */
115 0, /* tp_as_sequence */
116 0, /* tp_as_mapping */
117 0, /* tp_hash */
118 0, /* tp_call */
119 0, /* tp_str */
120 PyObject_GenericGetAttr, /* tp_getattro */
121 0, /* tp_setattro */
122 0, /* tp_as_buffer */
123 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
124 Py_TPFLAGS_BASETYPE, /* tp_flags */
125 enum_doc, /* tp_doc */
126 (traverseproc)enum_traverse, /* tp_traverse */
127 0, /* tp_clear */
128 0, /* tp_richcompare */
129 0, /* tp_weaklistoffset */
130 PyObject_SelfIter, /* tp_iter */
131 (iternextfunc)enum_next, /* tp_iternext */
132 0, /* tp_methods */
133 0, /* tp_members */
134 0, /* tp_getset */
135 0, /* tp_base */
136 0, /* tp_dict */
137 0, /* tp_descr_get */
138 0, /* tp_descr_set */
139 0, /* tp_dictoffset */
140 0, /* tp_init */
141 PyType_GenericAlloc, /* tp_alloc */
142 enum_new, /* tp_new */
143 PyObject_GC_Del, /* tp_free */
144};
145
146/* Reversed Object ***************************************************************/
147
148typedef struct {
149 PyObject_HEAD
150 Py_ssize_t index;
151 PyObject* seq;
152} reversedobject;
153
154static PyObject *
155reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
156{
157 Py_ssize_t n;
158 PyObject *seq;
159 reversedobject *ro;
160
161 if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq))
162 return NULL;
163
164 if (PyObject_HasAttrString(seq, "__reversed__"))
165 return PyObject_CallMethod(seq, "__reversed__", NULL);
166
167 if (!PySequence_Check(seq)) {
168 PyErr_SetString(PyExc_TypeError,
169 "argument to reversed() must be a sequence");
170 return NULL;
171 }
172
173 n = PySequence_Size(seq);
174 if (n == -1)
175 return NULL;
176
177 ro = (reversedobject *)type->tp_alloc(type, 0);
178 if (ro == NULL)
179 return NULL;
180
181 ro->index = n-1;
182 Py_INCREF(seq);
183 ro->seq = seq;
184 return (PyObject *)ro;
185}
186
187static void
188reversed_dealloc(reversedobject *ro)
189{
190 PyObject_GC_UnTrack(ro);
191 Py_XDECREF(ro->seq);
192 ro->ob_type->tp_free(ro);
193}
194
195static int
196reversed_traverse(reversedobject *ro, visitproc visit, void *arg)
197{
198 Py_VISIT(ro->seq);
199 return 0;
200}
201
202static PyObject *
203reversed_next(reversedobject *ro)
204{
205 PyObject *item;
206 Py_ssize_t index = ro->index;
207
208 if (index >= 0) {
209 item = PySequence_GetItem(ro->seq, index);
210 if (item != NULL) {
211 ro->index--;
212 return item;
213 }
214 if (PyErr_ExceptionMatches(PyExc_IndexError) ||
215 PyErr_ExceptionMatches(PyExc_StopIteration))
216 PyErr_Clear();
217 }
218 ro->index = -1;
219 Py_CLEAR(ro->seq);
220 return NULL;
221}
222
223PyDoc_STRVAR(reversed_doc,
224"reversed(sequence) -> reverse iterator over values of the sequence\n"
225"\n"
226"Return a reverse iterator");
227
228static PyObject *
229reversed_len(reversedobject *ro)
230{
231 Py_ssize_t position, seqsize;
232
233 if (ro->seq == NULL)
234 return PyInt_FromLong(0);
235 seqsize = PySequence_Size(ro->seq);
236 if (seqsize == -1)
237 return NULL;
238 position = ro->index + 1;
239 return PyInt_FromSsize_t((seqsize < position) ? 0 : position);
240}
241
242PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
243
244static PyMethodDef reversediter_methods[] = {
245 {"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc},
246 {NULL, NULL} /* sentinel */
247};
248
249PyTypeObject PyReversed_Type = {
250 PyObject_HEAD_INIT(&PyType_Type)
251 0, /* ob_size */
252 "reversed", /* tp_name */
253 sizeof(reversedobject), /* tp_basicsize */
254 0, /* tp_itemsize */
255 /* methods */
256 (destructor)reversed_dealloc, /* tp_dealloc */
257 0, /* tp_print */
258 0, /* tp_getattr */
259 0, /* tp_setattr */
260 0, /* tp_compare */
261 0, /* tp_repr */
262 0, /* tp_as_number */
263 0, /* tp_as_sequence */
264 0, /* tp_as_mapping */
265 0, /* tp_hash */
266 0, /* tp_call */
267 0, /* tp_str */
268 PyObject_GenericGetAttr, /* tp_getattro */
269 0, /* tp_setattro */
270 0, /* tp_as_buffer */
271 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
272 Py_TPFLAGS_BASETYPE, /* tp_flags */
273 reversed_doc, /* tp_doc */
274 (traverseproc)reversed_traverse,/* tp_traverse */
275 0, /* tp_clear */
276 0, /* tp_richcompare */
277 0, /* tp_weaklistoffset */
278 PyObject_SelfIter, /* tp_iter */
279 (iternextfunc)reversed_next, /* tp_iternext */
280 reversediter_methods, /* tp_methods */
281 0, /* tp_members */
282 0, /* tp_getset */
283 0, /* tp_base */
284 0, /* tp_dict */
285 0, /* tp_descr_get */
286 0, /* tp_descr_set */
287 0, /* tp_dictoffset */
288 0, /* tp_init */
289 PyType_GenericAlloc, /* tp_alloc */
290 reversed_new, /* tp_new */
291 PyObject_GC_Del, /* tp_free */
292};
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