Hi, in lua source code lstrlib.c:
static lua_Integer unpackint (lua_State *L, const char *str,
int islittle, int size, int issigned) {
lua_Unsigned res = 0;
int i;
int limit = (size <= SZINT) ? size : SZINT;
for (i = limit - 1; i >= 0; i--) {
res <<= NB;
res |= (lua_Unsigned)(unsigned char)str[islittle ? i : size - 1 - i];
}
if (size < SZINT) { /* real size smaller than lua_Integer? */
if (issigned) { /* needs sign extension? */
lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
res = ((res ^ mask) - mask); /* do sign extension */
}
}
Does anyone know it can use "res = res - ((lua_Unsigned)1 << (size*NB));" instead of "lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1); res = ((res ^ mask) - mask);"?
