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new conversion float->integer: conversion is valid only when

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float has an exact representation as an integer
This commit is contained in:
Roberto Ierusalimschy
2014-07-17 09:30:53 -03:00
parent c229ed597f
commit 8bb272a3e3
4 changed files with 46 additions and 35 deletions
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22
lvm.c
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@@ -1,5 +1,5 @@
/*
** $Id: lvm.c,v 2.216 2014/06/19 18:27:20 roberto Exp roberto $
** $Id: lvm.c,v 2.217 2014/06/30 19:48:08 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -80,15 +80,23 @@ int luaV_tonumber_ (const TValue *obj, lua_Number *n) {
/*
** try to convert a value to an integer, rounding up if 'up' is true
** try to convert a value to an integer, rounding according to 'mode':
** mode == 0: accepts only integral values
** mode < 0: takes the floor of the number
** mode > 0: takes the ceil of the number
*/
static int tointeger_aux (const TValue *obj, lua_Integer *p, int up) {
static int tointeger_aux (const TValue *obj, lua_Integer *p, int mode) {
TValue v;
again:
if (ttisfloat(obj)) {
lua_Number n = fltvalue(obj);
n = (up ? -l_floor(-n) : l_floor(n));
return lua_numtointeger(n, p);
lua_Number f = l_floor(n);
if (n != f) { /* not an integral value? */
if (mode == 0) return 0; /* fails if mode demands integral value */
else if (mode > 0) /* needs ceil? */
f += 1; /* convert floor to ceil (remember: n != f) */
}
return lua_numtointeger(f, p);
}
else if (ttisinteger(obj)) {
*p = ivalue(obj);
@@ -104,7 +112,7 @@ static int tointeger_aux (const TValue *obj, lua_Integer *p, int up) {
/*
** try to convert a non-integer value to an integer, rounding down
** try to convert a value to an integer
*/
int luaV_tointeger_ (const TValue *obj, lua_Integer *p) {
return tointeger_aux(obj, p, 0);
@@ -155,7 +163,7 @@ int luaV_tostring (lua_State *L, StkId obj) {
static int forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
int *stopnow) {
*stopnow = 0; /* usually, let loops run */
if (!tointeger_aux(obj, p, (step < 0))) { /* does not fit in integer? */
if (!tointeger_aux(obj, p, (step < 0 ? 1 : -1))) { /* not fit in integer? */
lua_Number n; /* try to convert to float */
if (!tonumber(obj, &n)) /* cannot convert to float? */
return 0; /* not a number */