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using lua_Unsigned (instead of lua_Integer) for bit manipulation

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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
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15
lstrlib.c
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@@ -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 ** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h ** 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? */ if (size < SZINT) { /* need test for overflow? */
/* OK if there are only zeros left in higher bytes, /* OK if there are only zeros left in higher bytes,
or only ones left (excluding non-signal bits in last byte) */ or only ones left (excluding non-signal bits in last byte) */
return ((n & ~(lua_Integer)MC) == 0 || return ((n & ~(lua_Unsigned)MC) == 0 ||
(n | SM) == ~(lua_Integer)0); (n | SM) == ~(lua_Unsigned)0);
} }
else return 1; /* no overflow can occur with full size */ 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, static int undumpint (const char *buff, lua_Integer *res,
int littleendian, int size) { int littleendian, int size) {
lua_Integer n = 0; lua_Unsigned n = 0;
int i; int i;
for (i = 0; i < size; i++) { for (i = 0; i < size; i++) {
if (i >= SZINT) { /* will throw away a byte? */ if (i >= SZINT) { /* will throw away a byte? */
@@ -1053,13 +1053,14 @@ static int undumpint (const char *buff, lua_Integer *res,
return 0; /* overflow */ return 0; /* overflow */
} }
n <<= NB; 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? */ if (size < SZINT) { /* need sign extension? */
lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1); 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; return 1;
} }