diff options
| -rw-r--r-- | Lib/test/test_slice.py | 3 | ||||
| -rw-r--r-- | Objects/sliceobject.c | 18 |
2 files changed, 15 insertions, 6 deletions
diff --git a/Lib/test/test_slice.py b/Lib/test/test_slice.py index 7b3ee06..49ed20e 100644 --- a/Lib/test/test_slice.py +++ b/Lib/test/test_slice.py @@ -1,6 +1,7 @@ # tests for slice objects; in particular the indices method. from test.test_support import vereq +import sys vereq(slice(None ).indices(10), (0, 10, 1)) vereq(slice(None, None, 2).indices(10), (0, 10, 2)) @@ -11,3 +12,5 @@ vereq(slice(3, None, -2).indices(10), (3, -1, -2)) vereq(slice(-100, 100 ).indices(10), slice(None).indices(10)) vereq(slice(100, -100, -1).indices(10), slice(None, None, -1).indices(10)) vereq(slice(-100L, 100L, 2L).indices(10), (0, 10, 2)) + +vereq(range(10)[::sys.maxint - 1], [0]) diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c index 21426a7..a035e5f 100644 --- a/Objects/sliceobject.c +++ b/Objects/sliceobject.c @@ -114,11 +114,13 @@ PySlice_GetIndicesEx(PySliceObject *r, int length, int *start, int *stop, int *step, int *slicelength) { /* this is harder to get right than you might think */ + int defstart, defstop; if (r->step == Py_None) { *step = 1; - } else { + } + else { *step = PyInt_AsLong(r->step); if (*step == -1 && PyErr_Occurred()) { return -1; @@ -135,7 +137,8 @@ PySlice_GetIndicesEx(PySliceObject *r, int length, if (r->start == Py_None) { *start = defstart; - } else { + } + else { if (!_PyEval_SliceIndex(r->start, start)) return -1; if (*start < 0) *start += length; if (*start < 0) *start = (*step < 0) ? -1 : 0; @@ -145,19 +148,22 @@ PySlice_GetIndicesEx(PySliceObject *r, int length, if (r->stop == Py_None) { *stop = defstop; - } else { + } + else { if (!_PyEval_SliceIndex(r->stop, stop)) return -1; if (*stop < 0) *stop += length; if (*stop < 0) *stop = -1; if (*stop > length) *stop = length; } - - if ((*stop - *start)*(*step) <= 0) { + + if ((*step < 0 && *stop >= *start) + || (*step > 0 && *start >= *stop)) { *slicelength = 0; } else if (*step < 0) { *slicelength = (*stop-*start+1)/(*step)+1; - } else { + } + else { *slicelength = (*stop-*start-1)/(*step)+1; } |