Issue #27867: Replaced function PySlice_GetIndicesEx() with a macro.
diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c
index 3c996f9..ff9479e 100644
--- a/Objects/sliceobject.c
+++ b/Objects/sliceobject.c
@@ -131,13 +131,12 @@
}
int
-PySlice_GetIndicesEx(PySliceObject *r, Py_ssize_t length,
- Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)
+_PySlice_Unpack(PyObject *_r,
+ Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)
{
+ PySliceObject *r = (PySliceObject *)_r;
/* this is harder to get right than you might think */
- Py_ssize_t defstart, defstop;
-
if (r->step == Py_None) {
*step = 1;
}
@@ -150,42 +149,75 @@
}
}
- defstart = *step < 0 ? length-1 : 0;
- defstop = *step < 0 ? -1 : length;
-
if (r->start == Py_None) {
- *start = defstart;
+ *start = *step < 0 ? PY_SSIZE_T_MAX-1 : 0;;
}
else {
if (!_PyEval_SliceIndex(r->start, start)) return -1;
- if (*start < 0) *start += length;
- if (*start < 0) *start = (*step < 0) ? -1 : 0;
- if (*start >= length)
- *start = (*step < 0) ? length - 1 : length;
}
if (r->stop == Py_None) {
- *stop = defstop;
+ *stop = *step < 0 ? -PY_SSIZE_T_MAX : PY_SSIZE_T_MAX;
}
else {
if (!_PyEval_SliceIndex(r->stop, stop)) return -1;
- if (*stop < 0) *stop += length;
- if (*stop < 0) *stop = (*step < 0) ? -1 : 0;
- if (*stop >= length)
- *stop = (*step < 0) ? length - 1 : length;
}
- if ((*step < 0 && *stop >= *start)
- || (*step > 0 && *start >= *stop)) {
- *slicelength = 0;
+ return 0;
+}
+
+Py_ssize_t
+_PySlice_AdjustIndices(Py_ssize_t length,
+ Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)
+{
+ /* this is harder to get right than you might think */
+
+ assert(step != 0);
+ assert(step >= -PY_SSIZE_T_MAX);
+
+ if (*start < 0) {
+ *start += length;
+ if (*start < 0) {
+ *start = (step < 0) ? -1 : 0;
+ }
}
- else if (*step < 0) {
- *slicelength = (*stop-*start+1)/(*step)+1;
+ else if (*start >= length) {
+ *start = (step < 0) ? length - 1 : length;
+ }
+
+ if (*stop < 0) {
+ *stop += length;
+ if (*stop < 0) {
+ *stop = (step < 0) ? -1 : 0;
+ }
+ }
+ else if (*stop >= length) {
+ *stop = (step < 0) ? length - 1 : length;
+ }
+
+ if (step < 0) {
+ if (*stop < *start) {
+ return (*start - *stop - 1) / (-step) + 1;
+ }
}
else {
- *slicelength = (*stop-*start-1)/(*step)+1;
+ if (*start < *stop) {
+ return (*stop - *start - 1) / step + 1;
+ }
}
+ return 0;
+}
+#undef PySlice_GetIndicesEx
+
+int
+PySlice_GetIndicesEx(PySliceObject *r, Py_ssize_t length,
+ Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step,
+ Py_ssize_t *slicelength)
+{
+ if (_PySlice_Unpack((PyObject *)r, start, stop, step) < 0)
+ return -1;
+ *slicelength = _PySlice_AdjustIndices(length, start, stop, *step);
return 0;
}