static PyObject*
slice_indices(PySliceObject* self, PyObject* len)
{
PyObject *start, *stop, *step;
PyObject *length;
int error;
/* Convert length to an integer if necessary; raise for negative length. */
length = PyNumber_Index(len);
if (length == NULL)
return NULL;
if (_PyLong_Sign(length) < 0) {
PyErr_SetString(PyExc_ValueError,
"length should not be negative");
Py_DECREF(length);
return NULL;
}
error = _PySlice_GetLongIndices(self, length, &start, &stop, &step);
Py_DECREF(length);
if (error == -1)
return NULL;
else
return Py_BuildValue("(NNN)", start, stop, step);
}
static PyObject *
compute_slice(rangeobject *r, PyObject *_slice)
{
PySliceObject *slice = (PySliceObject *) _slice;
rangeobject *result;
PyObject *start = NULL, *stop = NULL, *step = NULL;
PyObject *substart = NULL, *substop = NULL, *substep = NULL;
int error;
error = _PySlice_GetLongIndices(slice, r->length, &start, &stop, &step);
if (error == -1)
return NULL;
substep = PyNumber_Multiply(r->step, step);
if (substep == NULL) goto fail;
Py_CLEAR(step);
substart = compute_item(r, start);
if (substart == NULL) goto fail;
Py_CLEAR(start);
substop = compute_item(r, stop);
if (substop == NULL) goto fail;
Py_CLEAR(stop);
result = make_range_object(Py_TYPE(r), substart, substop, substep);
if (result != NULL) {
return (PyObject *) result;
}
fail:
Py_XDECREF(start);
Py_XDECREF(stop);
Py_XDECREF(step);
Py_XDECREF(substart);
Py_XDECREF(substop);
Py_XDECREF(substep);
return NULL;
}
