Issue #6334: Fix buggy internal length calculation in builtin range function
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index a62e124..fdb0ea2 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -924,6 +924,24 @@
self.assertEqual(list(range(1, 10, 3)), [1, 4, 7])
#self.assertEqual(list(range(5, -5, -3)), [5, 2, -1, -4])
+ #issue 6334: the internal stored range length was being
+ #computed incorrectly in some cases involving large arguments.
+ x = range(10**20, 10**20+10, 3)
+ self.assertEqual(len(x), 4)
+ self.assertEqual(len(list(x)), 4)
+
+ x = range(10**20+10, 10**20, 3)
+ self.assertEqual(len(x), 0)
+ self.assertEqual(len(list(x)), 0)
+
+ x = range(10**20, 10**20+10, -3)
+ self.assertEqual(len(x), 0)
+ self.assertEqual(len(list(x)), 0)
+
+ x = range(10**20+10, 10**20, -3)
+ self.assertEqual(len(x), 4)
+ self.assertEqual(len(list(x)), 4)
+
""" XXX(nnorwitz):
# Now test range() with longs
self.assertEqual(list(range(-2**100)), [])
diff --git a/Objects/rangeobject.c b/Objects/rangeobject.c
index f8174ca..11fd32e 100644
--- a/Objects/rangeobject.c
+++ b/Objects/rangeobject.c
@@ -581,7 +581,6 @@
{
rangeobject *r = (rangeobject *)seq;
longrangeiterobject *it;
- PyObject *tmp, *len;
long lstart, lstop, lstep;
assert(PyRange_Check(seq));
@@ -612,15 +611,9 @@
it->len = it->index = NULL;
- /* Calculate length: (r->stop - r->start) / r->step */
- tmp = PyNumber_Subtract(r->stop, r->start);
- if (!tmp)
+ it->len = range_length_obj(r);
+ if (!it->len)
goto create_failure;
- len = PyNumber_FloorDivide(tmp, r->step);
- Py_DECREF(tmp);
- if (!len)
- goto create_failure;
- it->len = len;
it->index = PyLong_FromLong(0);
if (!it->index)
goto create_failure;