Bug #76884 [Nab->Opn]: base_convert restore data not equal origin data

Edit report at https://bugs.php.net/bug.php?id=76884&edit=1 ID: 76884 User updated by: aston dot seal at gmail dot com Reported by: aston dot seal at gmail dot com Summary: base_convert restore data not equal origin data -Status: Not a bug +Status: Open Type: Bug -Package: *General Issues +Package: Math related Operating System: centos 7.4 PHP Version: 7.2.10 Block user comment: N Private report: N New Comment: change package Previous Comments: ------------------------------------------------------------------------ [2018-09-15 03:33:33] requinix@php.net Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php > Warning: base_convert() may lose precision on large numbers due to properties related to the > internal "double" or > "float" type used. Please see the Floating point numbers section in the manual for > more specific information and > limitations. You're trying to generate a unique identifier. There are better methods. ------------------------------------------------------------------------ [2018-09-15 03:24:50] aston dot seal at gmail dot com Description: ------------ --- From manual page: http://www.php.net/function.base-convert --- PHP Version : PHP 7.2.10 (cli) (built: Sep 11 2018 10:09:51) ( NTS ) when I using base_convert to make a order id for my system, I found it restore my data isn't correct, is it a bug ? origin_data always not equal recovery_data Test script: --------------- $a = '10010'.sprintf('%02d',mt_rand(0,99)).str_pad(str_replace('.', '', microtime(TRUE)), 14, 0, STR_PAD_RIGHT); echo 'origin_data : '.$a; echo '<br>'; $b = base_convert($a, 10,36); echo 'convert_data : '.$b; echo '<br>'; echo 'recovery_data : '.base_convert($b, 36,10); Expected result: ---------------- origin_data : 100106615369813329847 convert_data : l4k9ti8ikb4cg recovery_data : 100106615369813329847 Actual result: -------------- origin_data : 100106615369813329847 convert_data : l4k9ti8ikb4cg recovery_data : 100106615369813328882 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=76884&edit=1