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 *

    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

    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

    39 iter_traverse(seqiterobject *it, visitproc visit, void *arg)

    40 {

    41 	Py_VISIT(it->it_seq);

    42 	return 0;

    43 }

    44 

    45 static PyObject *

    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 *

    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 *

   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

   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

   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 *

   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 };