luaO_str2d, strtod and hexadecimal numbers under IRIX
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- Subject: luaO_str2d, strtod and hexadecimal numbers under IRIX
- From: "Rainer M. Canavan" <lua@...>
- Date: 2010年10月18日 23:01:43 +0200 (CEST)
Lua fails to parse hexadecimal numbers under IRIX (6.5.30),
evidently caused by a buggy strtod implementation. strtod just
doesn't advance the endpointer exactly if s starts with '0x'
('0y' or '1x' yield the expected result), so that (endptr == s)
holds and the conversion fails.
The modified luaO_str2d, the example program and its output
below illustrate the problem and a potential workaround:
int luaO_str2d (const char *s, lua_Number *result) {
char *endptr;
*result = lua_str2number(s, &endptr);
*result = strtod(s, &endptr);
printf("result %li\n", *result);
printf("endptr %s\n", endptr);
if ((*s == '0') &&
(*(s+1) == 'x' || *(s+1) == 'X')) /* maybe an hexadecimal constant? */
{
printf("hex %s\n", endptr);
*result = cast_num(strtoul(s, &endptr, 16));
}
if (endptr == s) return 0; /* conversion failed */
if (*endptr == '0円') return 1; /* most common case */
while (isspace(cast(unsigned char, *endptr))) endptr++;
if (*endptr != '0円') return 0; /* invalid trailing characters? */
return 1;
}
hex.lua:
print(0xff)
print(1xff)
Output:
result 0
endptr 0xff
hex 0xff
result 0
endptr xff
result 0
endptr xff
./lua: ../../hex.lua:2: malformed number near '1xff'