Bug #55393 [Opn->Csd]: base_convert makes negative numbers positive

Edit report at https://bugs.php.net/bug.php?id=55393&edit=1 ID: 55393 Updated by: cmb@php.net Reported by: phpbugs at ch dot pkts dot ca Summary: base_convert makes negative numbers positive -Status: Open +Status: Closed Type: Bug Package: Math related Operating System: Linux PHP Version: Irrelevant -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: Indeed, there is a warning as of PHP 7.4.0[1], and it is clearly documented that invalid characters are ignored[2]. [1] <https://3v4l.org/5jdrP> [2] <https://www.php.net/manual/en/function.base-convert.php#refsect1-function.base-convert-parameters> Previous Comments: ------------------------------------------------------------------------ [2019-07-11 20:22:43] Scott at exussum dot co dot uk This has been voted against and can be closed now https://wiki.php.net/rfc/base_convert_improvements The 64 bit version of PHP will solve this issue ------------------------------------------------------------------------ [2014-12-14 18:32:03] ffeast at gmail dot com Hi There's a simpler example: php -r 'print(base_convert(-5, 10, 2));' 101 So '-' is omitted. $ php -v PHP 5.5.9-1ubuntu4.4 (cli) (built: Sep 4 2014 06:57:30) Copyright (c) 1997-2014 The PHP Group Zend Engine v2.5.0, Copyright (c) 1998-2014 Zend Technologies with Zend OPcache v7.0.3, Copyright (c) 1999-2014, by Zend Technologies uname -a Linux Oleg 3.13.0-34-generic #60-Ubuntu SMP Wed Aug 13 15:49:09 UTC 2014 i686 i686 i686 GNU/Linux This is why it happens: https://github.com/php/php-src/blob/php-5.5.9/ext/standard/math.c#L869 any char except '0'..'9', 'a'..'z', 'A'..'Z' is simp ly left out without warnings :-( ------------------------------------------------------------------------ [2011-08-10 18:20:58] phpbugs at ch dot pkts dot ca Description: ------------ I'd created a fake email code fragment: e-mail: foo.<?php echo base_convert(time(),10,36).".".base_convert(ip2long($_SERVER['REMOTE_ADDR']),10,36) ?>@mydomain.com However, long2ip(base_convert("cxcapb",36,10)) gave the wrong answer (should be 209.105.205.209, got 46.150.50.47) It turns out that base_convert(...,10,36) should have returned -cxcapb instead of cxcapb, since ip2long("209.105.205.209") = -781595183 and ip2long("46.150.50.47") = 781595183. At this point, I'm not sure if there's legions of programs that work around this bug and would be broken by a fix. Test script: --------------- $a=base_convert(-781595183,10,36); if (base_convert($a,36,10) != -781595183) { echo "fail\n"; } else { echo "success\!"; } Expected result: ---------------- success! Actual result: -------------- fail ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=55393&edit=1