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author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2013-07-09 15:01:41 -0300 |
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committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2013-07-09 15:01:41 -0300 |
commit | 42cf5f8214edf45400c7e4abd6faef27cf424801 (patch) | |
tree | 7cf85dd6f3b3ce8d1da2eac310aa795add1233d3 | |
parent | d2209c07419aac2cac63dd6d31f5e886a2fdf7fa (diff) | |
download | lua-github-42cf5f8214edf45400c7e4abd6faef27cf424801.tar.gz |
avoid undefined shift of LUA_NBITS in rotate operations
-rw-r--r-- | lbitlib.c | 5 |
1 files changed, 3 insertions, 2 deletions
@@ -1,5 +1,5 @@ /* -** $Id: lbitlib.c,v 1.18 2013/03/19 13:19:12 roberto Exp $ +** $Id: lbitlib.c,v 1.18.1.1 2013/04/12 18:48:47 roberto Exp roberto $ ** Standard library for bitwise operations ** See Copyright Notice in lua.h */ @@ -129,7 +129,8 @@ static int b_rot (lua_State *L, int i) { b_uint 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; } |