1 /* Iterator objects */
2
3 #include "Python.h"
4
5 typedef struct {
6 PyObject_HEAD
7 long it_index;
8 PyObject *it_seq; /* Set to NULL when iterator is exhausted */
9 } seqiterobject;
10
11 PyObject *
PySeqIter_New(PyObject * seq)12 PySeqIter_New(PyObject *seq)
13 {
14 seqiterobject *it;
15
16 if (!PySequence_Check(seq)) {
17 PyErr_BadInternalCall();
18 return NULL;
19 }
20 it = PyObject_GC_New(seqiterobject, &PySeqIter_Type);
21 if (it == NULL)
22 return NULL;
23 it->it_index = 0;
24 Py_INCREF(seq);
25 it->it_seq = seq;
26 _PyObject_GC_TRACK(it);
27 return (PyObject *)it;
28 }
29
30 static void
iter_dealloc(seqiterobject * it)31 iter_dealloc(seqiterobject *it)
32 {
33 _PyObject_GC_UNTRACK(it);
34 Py_XDECREF(it->it_seq);
35 PyObject_GC_Del(it);
36 }
37
38 static int
iter_traverse(seqiterobject * it,visitproc visit,void * arg)39 iter_traverse(seqiterobject *it, visitproc visit, void *arg)
40 {
41 Py_VISIT(it->it_seq);
42 return 0;
43 }
44
45 static PyObject *
iter_iternext(PyObject * iterator)46 iter_iternext(PyObject *iterator)
47 {
48 seqiterobject *it;
49 PyObject *seq;
50 PyObject *result;
51
52 assert(PySeqIter_Check(iterator));
53 it = (seqiterobject *)iterator;
54 seq = it->it_seq;
55 if (seq == NULL)
56 return NULL;
57
58 result = PySequence_GetItem(seq, it->it_index);
59 if (result != NULL) {
60 it->it_index++;
61 return result;
62 }
63 if (PyErr_ExceptionMatches(PyExc_IndexError) ||
64 PyErr_ExceptionMatches(PyExc_StopIteration))
65 {
66 PyErr_Clear();
67 Py_DECREF(seq);
68 it->it_seq = NULL;
69 }
70 return NULL;
71 }
72
73 static PyObject *
iter_len(seqiterobject * it)74 iter_len(seqiterobject *it)
75 {
76 Py_ssize_t seqsize, len;
77
78 if (it->it_seq) {
79 seqsize = PySequence_Size(it->it_seq);
80 if (seqsize == -1)
81 return NULL;
82 len = seqsize - it->it_index;
83 if (len >= 0)
84 return PyInt_FromSsize_t(len);
85 }
86 return PyInt_FromLong(0);
87 }
88
89 PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
90
91 static PyMethodDef seqiter_methods[] = {
92 {"__length_hint__", (PyCFunction)iter_len, METH_NOARGS, length_hint_doc},
93 {NULL, NULL} /* sentinel */
94 };
95
96 PyTypeObject PySeqIter_Type = {
97 PyVarObject_HEAD_INIT(&PyType_Type, 0)
98 "iterator", /* tp_name */
99 sizeof(seqiterobject), /* tp_basicsize */
100 0, /* tp_itemsize */
101 /* methods */
102 (destructor)iter_dealloc, /* tp_dealloc */
103 0, /* tp_print */
104 0, /* tp_getattr */
105 0, /* tp_setattr */
106 0, /* tp_compare */
107 0, /* tp_repr */
108 0, /* tp_as_number */
109 0, /* tp_as_sequence */
110 0, /* tp_as_mapping */
111 0, /* tp_hash */
112 0, /* tp_call */
113 0, /* tp_str */
114 PyObject_GenericGetAttr, /* tp_getattro */
115 0, /* tp_setattro */
116 0, /* tp_as_buffer */
117 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
118 0, /* tp_doc */
119 (traverseproc)iter_traverse, /* tp_traverse */
120 0, /* tp_clear */
121 0, /* tp_richcompare */
122 0, /* tp_weaklistoffset */
123 PyObject_SelfIter, /* tp_iter */
124 iter_iternext, /* tp_iternext */
125 seqiter_methods, /* tp_methods */
126 0, /* tp_members */
127 };
128
129 /* -------------------------------------- */
130
131 typedef struct {
132 PyObject_HEAD
133 PyObject *it_callable; /* Set to NULL when iterator is exhausted */
134 PyObject *it_sentinel; /* Set to NULL when iterator is exhausted */
135 } calliterobject;
136
137 PyObject *
PyCallIter_New(PyObject * callable,PyObject * sentinel)138 PyCallIter_New(PyObject *callable, PyObject *sentinel)
139 {
140 calliterobject *it;
141 it = PyObject_GC_New(calliterobject, &PyCallIter_Type);
142 if (it == NULL)
143 return NULL;
144 Py_INCREF(callable);
145 it->it_callable = callable;
146 Py_INCREF(sentinel);
147 it->it_sentinel = sentinel;
148 _PyObject_GC_TRACK(it);
149 return (PyObject *)it;
150 }
151 static void
calliter_dealloc(calliterobject * it)152 calliter_dealloc(calliterobject *it)
153 {
154 _PyObject_GC_UNTRACK(it);
155 Py_XDECREF(it->it_callable);
156 Py_XDECREF(it->it_sentinel);
157 PyObject_GC_Del(it);
158 }
159
160 static int
calliter_traverse(calliterobject * it,visitproc visit,void * arg)161 calliter_traverse(calliterobject *it, visitproc visit, void *arg)
162 {
163 Py_VISIT(it->it_callable);
164 Py_VISIT(it->it_sentinel);
165 return 0;
166 }
167
168 static PyObject *
calliter_iternext(calliterobject * it)169 calliter_iternext(calliterobject *it)
170 {
171 if (it->it_callable != NULL) {
172 PyObject *args = PyTuple_New(0);
173 PyObject *result;
174 if (args == NULL)
175 return NULL;
176 result = PyObject_Call(it->it_callable, args, NULL);
177 Py_DECREF(args);
178 if (result != NULL) {
179 int ok;
180 ok = PyObject_RichCompareBool(result,
181 it->it_sentinel,
182 Py_EQ);
183 if (ok == 0)
184 return result; /* Common case, fast path */
185 Py_DECREF(result);
186 if (ok > 0) {
187 Py_CLEAR(it->it_callable);
188 Py_CLEAR(it->it_sentinel);
189 }
190 }
191 else if (PyErr_ExceptionMatches(PyExc_StopIteration)) {
192 PyErr_Clear();
193 Py_CLEAR(it->it_callable);
194 Py_CLEAR(it->it_sentinel);
195 }
196 }
197 return NULL;
198 }
199
200 PyTypeObject PyCallIter_Type = {
201 PyVarObject_HEAD_INIT(&PyType_Type, 0)
202 "callable-iterator", /* tp_name */
203 sizeof(calliterobject), /* tp_basicsize */
204 0, /* tp_itemsize */
205 /* methods */
206 (destructor)calliter_dealloc, /* tp_dealloc */
207 0, /* tp_print */
208 0, /* tp_getattr */
209 0, /* tp_setattr */
210 0, /* tp_compare */
211 0, /* tp_repr */
212 0, /* tp_as_number */
213 0, /* tp_as_sequence */
214 0, /* tp_as_mapping */
215 0, /* tp_hash */
216 0, /* tp_call */
217 0, /* tp_str */
218 PyObject_GenericGetAttr, /* tp_getattro */
219 0, /* tp_setattro */
220 0, /* tp_as_buffer */
221 Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
222 0, /* tp_doc */
223 (traverseproc)calliter_traverse, /* tp_traverse */
224 0, /* tp_clear */
225 0, /* tp_richcompare */
226 0, /* tp_weaklistoffset */
227 PyObject_SelfIter, /* tp_iter */
228 (iternextfunc)calliter_iternext, /* tp_iternext */
229 0, /* tp_methods */
230 };
231