From: Victor Stinner <victor.stinner@gmail.com>
Date: Mon, 7 May 2012 21:50:05 +0000 (+0200)
Subject: Backout ab500b297900: the check for integer overflow is wrong
X-Git-Tag: v3.3.0a4~230
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=106802547c0180a29a8a55640d1f5b8ae670d657;p=python

Backout ab500b297900: the check for integer overflow is wrong

Issue #14716: Change integer overflow check in unicode_writer_prepare()
to compute the limit at compile time instead of runtime. Patch writen by Serhiy
Storchaka.
---

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 4bbaa35891..0722312373 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -13242,10 +13242,8 @@ unicode_writer_prepare(unicode_writer_t *writer,
     newlen = writer->pos + length;
 
     if (newlen > PyUnicode_GET_LENGTH(writer->buffer)) {
-        /* Overallocate 25% to limit the number of resize.
-           Check for integer overflow:
-           (newlen + newlen / 4) <= PY_SSIZE_T_MAX */
-        if (newlen <= (PY_SSIZE_T_MAX - PY_SSIZE_T_MAX / 5))
+        /* overallocate 25% to limit the number of resize */
+        if (newlen <= (PY_SSIZE_T_MAX - newlen / 4))
             newlen += newlen / 4;
 
         if (maxchar > writer->maxchar) {