Staging
v0.8.1
v0.8.1
swh:1:snp:635f4099902912592851108bcac178ff574f7c5f
Tip revision: 1da43e5e916949c8e849e656d9d05fa4b9d6836c authored by Benjamin Peterson on 26 June 2009, 13:21:52 UTC
rearrange the sections of the README, so they'll hopefully be more in the order people will interested in
rearrange the sections of the README, so they'll hopefully be more in the order people will interested in
Tip revision: 1da43e5
enumobject.c
/* enumerate object */
#include "Python.h"
typedef struct {
PyObject_HEAD
Py_ssize_t en_index; /* current index of enumeration */
PyObject* en_sit; /* secondary iterator of enumeration */
PyObject* en_result; /* result tuple */
PyObject* en_longindex; /* index for sequences >= PY_SSIZE_T_MAX */
} enumobject;
static PyObject *
enum_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
enumobject *en;
PyObject *seq = NULL;
PyObject *start = NULL;
static char *kwlist[] = {"iterable", "start", 0};
if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:enumerate", kwlist,
&seq, &start))
return NULL;
en = (enumobject *)type->tp_alloc(type, 0);
if (en == NULL)
return NULL;
if (start != NULL) {
start = PyNumber_Index(start);
if (start == NULL) {
Py_DECREF(en);
return NULL;
}
assert(PyLong_Check(start));
en->en_index = PyLong_AsSsize_t(start);
if (en->en_index == -1 && PyErr_Occurred()) {
PyErr_Clear();
en->en_index = PY_SSIZE_T_MAX;
en->en_longindex = start;
} else {
en->en_longindex = NULL;
Py_DECREF(start);
}
} else {
en->en_index = 0;
en->en_longindex = NULL;
}
en->en_sit = PyObject_GetIter(seq);
if (en->en_sit == NULL) {
Py_DECREF(en);
return NULL;
}
en->en_result = PyTuple_Pack(2, Py_None, Py_None);
if (en->en_result == NULL) {
Py_DECREF(en);
return NULL;
}
return (PyObject *)en;
}
static void
enum_dealloc(enumobject *en)
{
PyObject_GC_UnTrack(en);
Py_XDECREF(en->en_sit);
Py_XDECREF(en->en_result);
Py_XDECREF(en->en_longindex);
Py_TYPE(en)->tp_free(en);
}
static int
enum_traverse(enumobject *en, visitproc visit, void *arg)
{
Py_VISIT(en->en_sit);
Py_VISIT(en->en_result);
Py_VISIT(en->en_longindex);
return 0;
}
static PyObject *
enum_next_long(enumobject *en, PyObject* next_item)
{
static PyObject *one = NULL;
PyObject *result = en->en_result;
PyObject *next_index;
PyObject *stepped_up;
if (en->en_longindex == NULL) {
en->en_longindex = PyLong_FromSsize_t(PY_SSIZE_T_MAX);
if (en->en_longindex == NULL)
return NULL;
}
if (one == NULL) {
one = PyLong_FromLong(1);
if (one == NULL)
return NULL;
}
next_index = en->en_longindex;
assert(next_index != NULL);
stepped_up = PyNumber_Add(next_index, one);
if (stepped_up == NULL)
return NULL;
en->en_longindex = stepped_up;
if (result->ob_refcnt == 1) {
Py_INCREF(result);
Py_DECREF(PyTuple_GET_ITEM(result, 0));
Py_DECREF(PyTuple_GET_ITEM(result, 1));
} else {
result = PyTuple_New(2);
if (result == NULL) {
Py_DECREF(next_index);
Py_DECREF(next_item);
return NULL;
}
}
PyTuple_SET_ITEM(result, 0, next_index);
PyTuple_SET_ITEM(result, 1, next_item);
return result;
}
static PyObject *
enum_next(enumobject *en)
{
PyObject *next_index;
PyObject *next_item;
PyObject *result = en->en_result;
PyObject *it = en->en_sit;
next_item = (*Py_TYPE(it)->tp_iternext)(it);
if (next_item == NULL)
return NULL;
if (en->en_index == PY_SSIZE_T_MAX)
return enum_next_long(en, next_item);
next_index = PyLong_FromSsize_t(en->en_index);
if (next_index == NULL) {
Py_DECREF(next_item);
return NULL;
}
en->en_index++;
if (result->ob_refcnt == 1) {
Py_INCREF(result);
Py_DECREF(PyTuple_GET_ITEM(result, 0));
Py_DECREF(PyTuple_GET_ITEM(result, 1));
} else {
result = PyTuple_New(2);
if (result == NULL) {
Py_DECREF(next_index);
Py_DECREF(next_item);
return NULL;
}
}
PyTuple_SET_ITEM(result, 0, next_index);
PyTuple_SET_ITEM(result, 1, next_item);
return result;
}
PyDoc_STRVAR(enum_doc,
"enumerate(iterable) -> iterator for index, value of iterable\n"
"\n"
"Return an enumerate object. iterable must be an other object that supports\n"
"iteration. The enumerate object yields pairs containing a count (from\n"
"zero) and a value yielded by the iterable argument. enumerate is useful\n"
"for obtaining an indexed list: (0, seq[0]), (1, seq[1]), (2, seq[2]), ...");
PyTypeObject PyEnum_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"enumerate", /* tp_name */
sizeof(enumobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)enum_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE, /* tp_flags */
enum_doc, /* tp_doc */
(traverseproc)enum_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)enum_next, /* tp_iternext */
0, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
enum_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};
/* Reversed Object ***************************************************************/
typedef struct {
PyObject_HEAD
Py_ssize_t index;
PyObject* seq;
} reversedobject;
static PyObject *
reversed_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
Py_ssize_t n;
PyObject *seq, *reversed_meth;
static PyObject *reversed_cache = NULL;
reversedobject *ro;
if (type == &PyReversed_Type && !_PyArg_NoKeywords("reversed()", kwds))
return NULL;
if (!PyArg_UnpackTuple(args, "reversed", 1, 1, &seq) )
return NULL;
reversed_meth = _PyObject_LookupSpecial(seq, "__reversed__", &reversed_cache);
if (reversed_meth != NULL) {
PyObject *res = PyObject_CallFunctionObjArgs(reversed_meth, NULL);
Py_DECREF(reversed_meth);
return res;
}
else if (PyErr_Occurred())
return NULL;
if (!PySequence_Check(seq)) {
PyErr_SetString(PyExc_TypeError,
"argument to reversed() must be a sequence");
return NULL;
}
n = PySequence_Size(seq);
if (n == -1)
return NULL;
ro = (reversedobject *)type->tp_alloc(type, 0);
if (ro == NULL)
return NULL;
ro->index = n-1;
Py_INCREF(seq);
ro->seq = seq;
return (PyObject *)ro;
}
static void
reversed_dealloc(reversedobject *ro)
{
PyObject_GC_UnTrack(ro);
Py_XDECREF(ro->seq);
Py_TYPE(ro)->tp_free(ro);
}
static int
reversed_traverse(reversedobject *ro, visitproc visit, void *arg)
{
Py_VISIT(ro->seq);
return 0;
}
static PyObject *
reversed_next(reversedobject *ro)
{
PyObject *item;
Py_ssize_t index = ro->index;
if (index >= 0) {
item = PySequence_GetItem(ro->seq, index);
if (item != NULL) {
ro->index--;
return item;
}
if (PyErr_ExceptionMatches(PyExc_IndexError) ||
PyErr_ExceptionMatches(PyExc_StopIteration))
PyErr_Clear();
}
ro->index = -1;
Py_CLEAR(ro->seq);
return NULL;
}
PyDoc_STRVAR(reversed_doc,
"reversed(sequence) -> reverse iterator over values of the sequence\n"
"\n"
"Return a reverse iterator");
static PyObject *
reversed_len(reversedobject *ro)
{
Py_ssize_t position, seqsize;
if (ro->seq == NULL)
return PyLong_FromLong(0);
seqsize = PySequence_Size(ro->seq);
if (seqsize == -1)
return NULL;
position = ro->index + 1;
return PyLong_FromSsize_t((seqsize < position) ? 0 : position);
}
PyDoc_STRVAR(length_hint_doc, "Private method returning an estimate of len(list(it)).");
static PyMethodDef reversediter_methods[] = {
{"__length_hint__", (PyCFunction)reversed_len, METH_NOARGS, length_hint_doc},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyReversed_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"reversed", /* tp_name */
sizeof(reversedobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)reversed_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_reserved */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
0, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE, /* tp_flags */
reversed_doc, /* tp_doc */
(traverseproc)reversed_traverse,/* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)reversed_next, /* tp_iternext */
reversediter_methods, /* tp_methods */
0, /* tp_members */
0, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
0, /* tp_dictoffset */
0, /* tp_init */
PyType_GenericAlloc, /* tp_alloc */
reversed_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};