/Objects/iterobject.c

  1/* Iterator objects */
  2
  3#include "Python.h"
  4
  5typedef struct {
  6	PyObject_HEAD
  7	long      it_index;
  8	PyObject *it_seq; /* Set to NULL when iterator is exhausted */
  9} seqiterobject;
 10
 11PyObject *
 12PySeqIter_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
 30static void
 31iter_dealloc(seqiterobject *it)
 32{
 33	_PyObject_GC_UNTRACK(it);
 34	Py_XDECREF(it->it_seq);
 35	PyObject_GC_Del(it);
 36}
 37
 38static int
 39iter_traverse(seqiterobject *it, visitproc visit, void *arg)
 40{
 41	Py_VISIT(it->it_seq);
 42	return 0;
 43}
 44
 45static PyObject *
 46iter_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
 73static PyObject *
 74iter_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
 89PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
 90
 91static PyMethodDef seqiter_methods[] = {
 92	{"__length_hint__", (PyCFunction)iter_len, METH_NOARGS, length_hint_doc},
 93 	{NULL,		NULL}		/* sentinel */
 94};
 95
 96PyTypeObject 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
131typedef 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
137PyObject *
138PyCallIter_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}
151static void
152calliter_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
160static int
161calliter_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
168static PyObject *
169calliter_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
200PyTypeObject 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};