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commit 2ef9bcfd118f263c06abfe2c04fe79a530ebe163
parent 5fa680d47f36d2f54d436d47beee2cb7dcf986cb
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Tue,  9 Jul 2013 15:30:36 -0300

avoid undefined shift of LUA_NBITS in rotate operation

Diffstat:
Mlbitlib.c | 5+++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lbitlib.c b/lbitlib.c @@ -1,5 +1,5 @@ /* -** $Id: lbitlib.c,v 1.20 2013/06/21 17:27:24 roberto Exp roberto $ +** $Id: lbitlib.c,v 1.21 2013/07/09 17:49:50 roberto Exp roberto $ ** Standard library for bitwise operations ** See Copyright Notice in lua.h */ @@ -128,7 +128,8 @@ static int b_rot (lua_State *L, int i) { lua_Unsigned r = luaL_checkunsigned(L, 1); i &= (LUA_NBITS - 1); /* i = i % NBITS */ r = trim(r); - r = (r << i) | (r >> (LUA_NBITS - i)); + if (i != 0) /* avoid undefined shift of LUA_NBITS when i == 0 */ + r = (r << i) | (r >> (LUA_NBITS - i)); lua_pushunsigned(L, trim(r)); return 1; }