From: Raymond Hettinger <python@rcn.com>
Date: Sun, 1 Mar 2015 08:38:00 +0000 (-0800)
Subject: Issue #23553:  Use an unsigned cast to tighten-up the bounds checking logic.
X-Git-Tag: v3.5.0a2~60
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7f9ea7543ecc978a636f2b0b5b28e0820644a312;p=python

Issue #23553:  Use an unsigned cast to tighten-up the bounds checking logic.
---

diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 0ca9be1df5..69814bb34c 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -772,7 +772,7 @@ deque_item(dequeobject *deque, Py_ssize_t i)
     PyObject *item;
     Py_ssize_t n, index=i;
 
-    if (i < 0 || i >= Py_SIZE(deque)) {
+    if ((size_t)i >= (size_t)Py_SIZE(deque)) {
         PyErr_SetString(PyExc_IndexError,
                         "deque index out of range");
         return NULL;
@@ -836,7 +836,7 @@ deque_ass_item(dequeobject *deque, Py_ssize_t i, PyObject *v)
     block *b;
     Py_ssize_t n, len=Py_SIZE(deque), halflen=(len+1)>>1, index=i;
 
-    if (i < 0 || i >= len) {
+    if ((size_t)i >= (size_t)len) {
         PyErr_SetString(PyExc_IndexError,
                         "deque index out of range");
         return -1;