Re: PHP 4.0 Bug #5404 Updated: String conversion to integer is incorrect

Good morning! > ID: 5404 > Updated by: stas > Reported By: kix@struktuur.ee > Status: Open > Bug Type: Scripting Engine problem > Assigned To: > Comments: > > It's not really PHP. It's C's strtod() function which is to blame. It > does > very strange tricks when it meets 0x-numbers. > So, "0x2f" converted by strtod into 1072693248. > > Full Bug description available at: http://bugs.php.net/?id=5404 Yes, it is true that strtod behaves very strangely when it encounters a hex number. But after looking at the sources of php it seems to me that the check, whether the string is an integer or double not, is done in the function is_numeric_string in the zend engine. Well if it is, then it seems to me that, it is that function too which is broken in the way it handles hexadecimal strings. The lines that check if the string is an integer are these: (taken from Zend/zend_operators.h) local_lval = strtol(str, &end_ptr, 10); if (errno!=ERANGE && end_ptr == str+length) { /* integer string */ and if this check fails, then it is checked if the string is a double, like this: local_dval = strtod(str, &end_ptr); if (errno!=ERANGE && end_ptr == str+length) { /* floating point string The problem is that the base is specified when calling the strtol function, as 10, leaving no room for finding octal or hex values. It seems to me that if the base was specified as 0, in which case the function tries to detect it itself, things would work quite nicely. Or, if it is undesirable to convert hex strings to integers a check could be added by trying to convert it like this, if the first conversion fails: local_lval = strtol(str, &end_ptr, 16); if (errno != ERANGE && end_ptr == str+length) { /* hex integer string */ and returning a 0 value, like php3 did in this case. Kristo.