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authorMark Dickinson <mdickinson@enthought.com>2011-09-24 07:56:09 (GMT)
committerMark Dickinson <mdickinson@enthought.com>2011-09-24 07:56:09 (GMT)
commitb2f6bc72a269a0c4ed389ad232b47e2a42b8dde0 (patch)
treeb1e691ab2afcc804385f38036708f598377a0051 /Modules
parentadde86d0e31ce486e72a9d1a2a7625e5e34d97e9 (diff)
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Issue #12973: Fix itertools bug caused by signed integer overflow. Thanks Stefan Krah.
Diffstat (limited to 'Modules')
-rw-r--r--Modules/itertoolsmodule.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 71d5bb6..8b6fa85 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -1234,7 +1234,9 @@ islice_next(isliceobject *lz)
return NULL;
lz->cnt++;
oldnext = lz->next;
- lz->next += lz->step;
+ /* The (size_t) cast below avoids the danger of undefined
+ behaviour from signed integer overflow. */
+ lz->next += (size_t)lz->step;
if (lz->next < oldnext || (stop != -1 && lz->next > stop))
lz->next = stop;
return item;