using lua_Unsigned (instead of lua_Integer) for bit manipulation

This commit is contained in:
Roberto Ierusalimschy 2014-04-27 11:42:26 -03:00
parent e98ba351ce
commit 68616c6669
1 changed files with 8 additions and 7 deletions

View File

@ -1,5 +1,5 @@
/*
** $Id: lstrlib.c,v 1.196 2014/04/14 16:59:46 roberto Exp roberto $
** $Id: lstrlib.c,v 1.197 2014/04/16 18:48:31 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
@ -1013,8 +1013,8 @@ static int dumpint (char *buff, lua_Integer m, int littleendian, int size) {
if (size < SZINT) { /* need test for overflow? */
/* OK if there are only zeros left in higher bytes,
or only ones left (excluding non-signal bits in last byte) */
return ((n & ~(lua_Integer)MC) == 0 ||
(n | SM) == ~(lua_Integer)0);
return ((n & ~(lua_Unsigned)MC) == 0 ||
(n | SM) == ~(lua_Unsigned)0);
}
else return 1; /* no overflow can occur with full size */
}
@ -1039,7 +1039,7 @@ static int dumpint_l (lua_State *L) {
static int undumpint (const char *buff, lua_Integer *res,
int littleendian, int size) {
lua_Integer n = 0;
lua_Unsigned n = 0;
int i;
for (i = 0; i < size; i++) {
if (i >= SZINT) { /* will throw away a byte? */
@ -1053,13 +1053,14 @@ static int undumpint (const char *buff, lua_Integer *res,
return 0; /* overflow */
}
n <<= NB;
n |= (lua_Integer)(unsigned char)buff[littleendian ? size - 1 - i : i];
n |= (lua_Unsigned)(unsigned char)buff[littleendian ? size - 1 - i : i];
}
if (size < SZINT) { /* need sign extension? */
lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
n = (lua_Integer)((n ^ mask) - mask); /* do sign extension */
*res = (lua_Integer)((n ^ mask) - mask); /* do sign extension */
}
*res = n;
else
*res = (lua_Integer)n;
return 1;
}