mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-09-19 23:20:25 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

Issues #16029, #16030: Fix pickling and repr of large xranges.

Browse source
This commit is contained in:
Mark Dickinson 2012-09-28 20:36:36 +01:00
parent 9faaf1b43e
commit 218a8ab5eb
3 changed files with 110 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

34
Objects/rangeobject.c
View file

@ -37,6 +37,30 @@ get_len_of_range(long lo, long hi, long step)
return 0UL;
}
/* Return a stop value suitable for reconstructing the xrange from
* a (start, stop, step) triple. Used in range_repr and range_reduce.
* Computes start + len * step, clipped to the range [LONG_MIN, LONG_MAX].
*/
static long
get_stop_for_range(rangeobject *r)
{
long last;
if (r->len == 0)
return r->start;
/* The tricky bit is avoiding overflow. We first compute the last entry in
the xrange, start + (len - 1) * step, which is guaranteed to lie within
the range of a long, and then add step to it. See the range_reverse
comments for an explanation of the casts below.
*/
last = (long)(r->start + (unsigned long)(r->len - 1) * r->step);
if (r->step > 0)
return last > LONG_MAX - r->step ? LONG_MAX : last + r->step;
else
return last < LONG_MIN - r->step ? LONG_MIN : last + r->step;
}
static PyObject *
range_new(PyTypeObject *type, PyObject *args, PyObject *kw)
{
@ -112,17 +136,17 @@ range_repr(rangeobject *r)
if (r->start == 0 && r->step == 1)
rtn = PyString_FromFormat("xrange(%ld)",
r->start + r->len * r->step);
get_stop_for_range(r));
else if (r->step == 1)
rtn = PyString_FromFormat("xrange(%ld, %ld)",
r->start,
r->start + r->len * r->step);
get_stop_for_range(r));
else
rtn = PyString_FromFormat("xrange(%ld, %ld, %ld)",
r->start,
r->start + r->len * r->step,
get_stop_for_range(r),
r->step);
return rtn;
}
@ -131,9 +155,9 @@ range_repr(rangeobject *r)
static PyObject *
range_reduce(rangeobject *r, PyObject *args)
{
return Py_BuildValue("(O(iii))", Py_TYPE(r),
return Py_BuildValue("(O(lll))", Py_TYPE(r),
r->start,
r->start + r->len * r->step,
get_stop_for_range(r),
r->step);
}