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Issue #28019: itertools.count() no longer rounds non-integer step in range

Browse source 
between 1.0 and 2.0 to 1.
This commit is contained in:
Serhiy Storchaka 2016-09-10 09:49:24 +03:00
parent e617521b0d
commit 8ddcf3abf7
3 changed files with 55 additions and 21 deletions
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45
Modules/itertoolsmodule.c
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@ -3905,7 +3905,7 @@ static PyObject *
count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
countobject *lz;
int slow_mode = 0;
int fast_mode;
Py_ssize_t cnt = 0;
PyObject *long_cnt = NULL;
PyObject *long_step = NULL;
@ -3922,16 +3922,26 @@ count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
return NULL;
}
fast_mode = (long_cnt == NULL || PyLong_Check(long_cnt)) &&
(long_step == NULL || PyLong_Check(long_step));
/* If not specified, start defaults to 0 */
if (long_cnt != NULL) {
cnt = PyLong_AsSsize_t(long_cnt);
if ((cnt == -1 && PyErr_Occurred()) || !PyLong_Check(long_cnt)) {
PyErr_Clear();
slow_mode = 1;
if (fast_mode) {
assert(PyLong_Check(long_cnt));
cnt = PyLong_AsSsize_t(long_cnt);
if (cnt == -1 && PyErr_Occurred()) {
PyErr_Clear();
fast_mode = 0;
}
}
Py_INCREF(long_cnt);
} else {
cnt = 0;
long_cnt = PyLong_FromLong(0);
if (long_cnt == NULL) {
return NULL;
}
}
/* If not specified, step defaults to 1 */
@ -3947,21 +3957,24 @@ count_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
assert(long_cnt != NULL && long_step != NULL);
/* Fast mode only works when the step is 1 */
step = PyLong_AsLong(long_step);
if (step != 1) {
slow_mode = 1;
if (step == -1 && PyErr_Occurred())
PyErr_Clear();
if (fast_mode) {
assert(PyLong_Check(long_step));
step = PyLong_AsLong(long_step);
if (step != 1) {
fast_mode = 0;
if (step == -1 && PyErr_Occurred())
PyErr_Clear();
}
}
if (slow_mode)
cnt = PY_SSIZE_T_MAX;
else
if (fast_mode)
Py_CLEAR(long_cnt);
else
cnt = PY_SSIZE_T_MAX;
assert((cnt != PY_SSIZE_T_MAX && long_cnt == NULL && !slow_mode) ||
(cnt == PY_SSIZE_T_MAX && long_cnt != NULL && slow_mode));
assert(slow_mode ||
assert((cnt != PY_SSIZE_T_MAX && long_cnt == NULL && fast_mode) ||
(cnt == PY_SSIZE_T_MAX && long_cnt != NULL && !fast_mode));
assert(!fast_mode ||
(PyLong_Check(long_step) && PyLong_AS_LONG(long_step) == 1));
/* create countobject structure */