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'lua_tounsigned' takes number modulo 2^numbits as a result when

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number is a float
(That may change...)
This commit is contained in:
Roberto Ierusalimschy 2013-06-04 16:34:51 -03:00
parent 188192ce9a
commit 932e7fb0e1
1 changed files with 28 additions and 2 deletions
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30
lapi.c
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@ -1,10 +1,11 @@
/*
** $Id: lapi.c,v 2.179 2013/05/02 12:37:24 roberto Exp roberto $
** $Id: lapi.c,v 2.180 2013/05/14 16:00:11 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/
#include <math.h>
#include <stdarg.h>
#include <string.h>
@ -376,7 +377,32 @@ LUA_API lua_Integer lua_tointegerx (lua_State *L, int idx, int *pisnum) {
LUA_API lua_Unsigned lua_tounsignedx (lua_State *L, int idx, int *pisnum) {
return lua_tointegerx(L, idx, pisnum); /* at least for now... <<<< */
lua_Unsigned res = 0;
const TValue *o = index2addr(L, idx);
int isnum = 0;
switch (ttype(o)) {
case LUA_TNUMINT: {
res = cast_unsigned(ivalue(o));
isnum = 1;
break;
}
case LUA_TNUMFLT: {
const lua_Number twop = (~(lua_Unsigned)0) + cast_num(1);
lua_Number n = fltvalue(o);
n = l_mathop(fmod)(n, twop);
n = l_mathop(floor)(n);
if (luai_numisnan(L,n)) /* not a number? */
break; /* not an integer, too */
if (n < 0)
n += twop; /* correct 'mod' */
res = cast_unsigned(n);
isnum = 1;
break;
}
default: break;
}
if (pisnum) *pisnum = isnum;
return res;
}