static PyObject *
range_iter(PyObject *seq)
{
rangeobject *r = (rangeobject *)seq;
longrangeiterobject *it;
long lstart, lstop, lstep;
PyObject *int_it;
assert(PyRange_Check(seq));
/* If all three fields and the length convert to long, use the int
* version */
lstart = PyLong_AsLong(r->start);
if (lstart == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstop = PyLong_AsLong(r->stop);
if (lstop == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstep = PyLong_AsLong(r->step);
if (lstep == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
int_it = fast_range_iter(lstart, lstop, lstep);
if (int_it == NULL && PyErr_ExceptionMatches(PyExc_OverflowError)) {
PyErr_Clear();
goto long_range;
}
return (PyObject *)int_it;
long_range:
it = PyObject_New(longrangeiterobject, &PyLongRangeIter_Type);
if (it == NULL)
return NULL;
/* Do all initialization here, so we can DECREF on failure. */
it->start = r->start;
it->step = r->step;
it->len = r->length;
Py_INCREF(it->start);
Py_INCREF(it->step);
Py_INCREF(it->len);
it->index = PyLong_FromLong(0);
if (!it->index)
goto create_failure;
return (PyObject *)it;
create_failure:
Py_DECREF(it);
return NULL;
}
static PyObject *
rangeiter_new(PyTypeObject *type, PyObject *args, PyObject *kw)
{
long start, stop, step;
if (!_PyArg_NoKeywords("rangeiter()", kw))
return NULL;
if (!PyArg_ParseTuple(args, "lll;rangeiter() requires 3 int arguments",
&start, &stop, &step))
return NULL;
return fast_range_iter(start, stop, step);
}
static PyObject *
range_iter(PyObject *seq)
{
rangeobject *r = (rangeobject *)seq;
longrangeiterobject *it;
long lstart, lstop, lstep;
PyObject *int_it;
assert(PyRange_Check(seq));
/* If all three fields and the length convert to long, use the int
* version */
lstart = PyLong_AsLong(r->start);
if (lstart == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstop = PyLong_AsLong(r->stop);
if (lstop == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstep = PyLong_AsLong(r->step);
if (lstep == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
int_it = fast_range_iter(lstart, lstop, lstep);
if (int_it == NULL && PyErr_ExceptionMatches(PyExc_OverflowError)) {
PyErr_Clear();
goto long_range;
}
return (PyObject *)int_it;
long_range:
it = PyObject_New(longrangeiterobject, &PyLongRangeIter_Type);
if (it == NULL)
return NULL;
it->start = r->start;
it->step = r->step;
it->len = r->length;
it->index = _PyLong_Zero;
Py_INCREF(it->start);
Py_INCREF(it->step);
Py_INCREF(it->len);
Py_INCREF(it->index);
return (PyObject *)it;
}
static PyObject *
range_reverse(PyObject *seq)
{
rangeobject *range = (rangeobject*) seq;
longrangeiterobject *it;
PyObject *one, *sum, *diff, *product;
long lstart, lstop, lstep, new_start, new_stop;
unsigned long ulen;
assert(PyRange_Check(seq));
/* reversed(range(start, stop, step)) can be expressed as
range(start+(n-1)*step, start-step, -step), where n is the number of
integers in the range.
If each of start, stop, step, -step, start-step, and the length
of the iterator is representable as a C long, use the int
version. This excludes some cases where the reversed range is
representable as a range_iterator, but it's good enough for
common cases and it makes the checks simple. */
lstart = PyLong_AsLong(range->start);
if (lstart == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstop = PyLong_AsLong(range->stop);
if (lstop == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
lstep = PyLong_AsLong(range->step);
if (lstep == -1 && PyErr_Occurred()) {
PyErr_Clear();
goto long_range;
}
/* check for possible overflow of -lstep */
if (lstep == LONG_MIN)
goto long_range;
/* check for overflow of lstart - lstep:
for lstep > 0, need only check whether lstart - lstep < LONG_MIN.
for lstep < 0, need only check whether lstart - lstep > LONG_MAX
Rearrange these inequalities as:
lstart - LONG_MIN < lstep (lstep > 0)
LONG_MAX - lstart < -lstep (lstep < 0)
and compute both sides as unsigned longs, to avoid the
possibility of undefined behaviour due to signed overflow. */
if (lstep > 0) {
if ((unsigned long)lstart - LONG_MIN < (unsigned long)lstep)
goto long_range;
}
else {
if (LONG_MAX - (unsigned long)lstart < 0UL - lstep)
goto long_range;
}
ulen = get_len_of_range(lstart, lstop, lstep);
if (ulen > (unsigned long)LONG_MAX)
goto long_range;
new_stop = lstart - lstep;
new_start = (long)(new_stop + ulen * lstep);
return fast_range_iter(new_start, new_stop, -lstep);
long_range:
it = PyObject_New(longrangeiterobject, &PyLongRangeIter_Type);
if (it == NULL)
return NULL;
/* start + (len - 1) * step */
it->len = range->length;
Py_INCREF(it->len);
one = PyLong_FromLong(1);
if (!one)
goto create_failure;
diff = PyNumber_Subtract(it->len, one);
Py_DECREF(one);
if (!diff)
goto create_failure;
product = PyNumber_Multiply(diff, range->step);
Py_DECREF(diff);
if (!product)
goto create_failure;
sum = PyNumber_Add(range->start, product);
Py_DECREF(product);
it->start = sum;
if (!it->start)
goto create_failure;
it->step = PyNumber_Negative(range->step);
if (!it->step)
goto create_failure;
it->index = PyLong_FromLong(0);
if (!it->index)
goto create_failure;
return (PyObject *)it;
create_failure:
Py_DECREF(it);
return NULL;
}
