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correct way (I hope) to convert floats to unsigned int

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Roberto Ierusalimschy 2013-06-14 15:32:45 -03:00
parent 0394314c7a
commit 53210d7e5b
1 changed files with 8 additions and 4 deletions
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12
lapi.c
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@ -1,5 +1,5 @@
/* /*
** $Id: lapi.c,v 2.180 2013/05/14 16:00:11 roberto Exp roberto $ ** $Id: lapi.c,v 2.181 2013/06/04 19:34:51 roberto Exp roberto $
** Lua API ** Lua API
** See Copyright Notice in lua.h ** See Copyright Notice in lua.h
*/ */
@ -389,13 +389,17 @@ LUA_API lua_Unsigned lua_tounsignedx (lua_State *L, int idx, int *pisnum) {
case LUA_TNUMFLT: { case LUA_TNUMFLT: {
const lua_Number twop = (~(lua_Unsigned)0) + cast_num(1); const lua_Number twop = (~(lua_Unsigned)0) + cast_num(1);
lua_Number n = fltvalue(o); lua_Number n = fltvalue(o);
n = l_mathop(fmod)(n, twop); int neg = 0;
n = l_mathop(floor)(n); n = l_mathop(floor)(n);
if (n < 0) {
neg = 1;
n = -n;
}
n = l_mathop(fmod)(n, twop);
if (luai_numisnan(L,n)) /* not a number? */ if (luai_numisnan(L,n)) /* not a number? */
break; /* not an integer, too */ break; /* not an integer, too */
if (n < 0)
n += twop; /* correct 'mod' */
res = cast_unsigned(n); res = cast_unsigned(n);
if (neg) res = -res;
isnum = 1; isnum = 1;
break; break;
} }