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DUALNUM: fix tonumber("-0")

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For DUALNUM build tonumber("-0x0") or tonumber("-0") returns 0 instead
-0 due to the STRSCAN_OPT_TOINT option of lj_strscan_scan and cast value
to integer with losing information about its sign.

This patch adds special checks for these corner cases during strscan.

Follows-up #528
This commit is contained in:
Sergey Kaplun 2021-12-22 23:30:48 +03:00
parent e73916d811
commit 09510c3902
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GPG Key ID: B185BA8E3C0A10B9
1 changed files with 16 additions and 4 deletions
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20
src/lj_strscan.c
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@ -121,7 +121,11 @@ static StrScanFmt strscan_hex(const uint8_t *p, TValue *o,
/* Format-specific handling. */
switch (fmt) {
case STRSCAN_INT:
if (!(opt & STRSCAN_OPT_TONUM) && x < 0x80000000u+neg) {
/* Need special check for 0 to be consistent with Lua 5.1
** behaviour in DUALNUM mode for tonumber "-0x0".
** See also https://github.com/LuaJIT/LuaJIT/issues/528.
*/
if (!(opt & STRSCAN_OPT_TONUM) && x < 0x80000000u+neg && x != 0) {
o->i = neg ? -(int32_t)x : (int32_t)x;
return STRSCAN_INT; /* Fast path for 32 bit integers. */
}
@ -445,7 +449,11 @@ StrScanFmt lj_strscan_scan(const uint8_t *p, TValue *o, uint32_t opt)
/* Fast path for decimal 32 bit integers. */
if (fmt == STRSCAN_INT && base == 10 &&
(dig < 10 || (dig == 10 && *sp <= '2' && x < 0x80000000u+neg))) {
if ((opt & STRSCAN_OPT_TONUM)) {
/* Need special check for 0 to be consistent with Lua 5.1
** behaviour in DUALNUM mode for tonumber "-0".
** See also https://github.com/LuaJIT/LuaJIT/issues/528.
*/
if ((opt & STRSCAN_OPT_TONUM) || x == 0) {
o->n = neg ? -(double)x : (double)x;
return STRSCAN_NUM;
} else {
@ -462,8 +470,12 @@ StrScanFmt lj_strscan_scan(const uint8_t *p, TValue *o, uint32_t opt)
else
fmt = strscan_dec(sp, o, fmt, opt, ex, neg, dig);
/* Try to convert number to integer, if requested. */
if (fmt == STRSCAN_NUM && (opt & STRSCAN_OPT_TOINT)) {
/* Try to convert number to integer, if requested.
** Need special check for 0 to be consistent with Lua 5.1
** behaviour in DUALNUM mode for tonumber "-0x0".
** See also https://github.com/LuaJIT/LuaJIT/issues/528.
*/
if (fmt == STRSCAN_NUM && (opt & STRSCAN_OPT_TOINT) && o->n != 0.) {
double n = o->n;
int32_t i = lj_num2int(n);
if (n == (lua_Number)i) { o->i = i; return STRSCAN_INT; }