From c9d1d9f9c6ce513c048eb85b99936ee241e5cd3b Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 9 Jun 2011 15:22:47 -0300
Subject: [PATCH] better way to test overflows with string indices

---
 lstrlib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lstrlib.c b/lstrlib.c
index 90dba169..c90297b2 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lstrlib.c,v 1.166 2011/04/20 16:36:28 roberto Exp roberto $
+** $Id: lstrlib.c,v 1.167 2011/05/03 16:01:57 roberto Exp roberto $
 ** Standard library for string operations and pattern-matching
 ** See Copyright Notice in lua.h
 */
@@ -45,7 +45,7 @@ static int str_len (lua_State *L) {
 /* translate a relative string position: negative means back from end */
 static size_t posrelat (ptrdiff_t pos, size_t len) {
   if (pos >= 0) return (size_t)pos;
-  else if (pos == -pos || (size_t)-pos > len) return 0;
+  else if (-(size_t)pos > len) return 0;
   else return len - ((size_t)-pos) + 1;
 }