Bug #61660 [Opn]: bin2hex(hex2bin($data)) != $data

Edit report at https://bugs.php.net/bug.php?id=61660&edit=1 ID: 61660 Updated by: rasmus@php.net Reported by: krtek4+php at gmail dot com Summary: bin2hex(hex2bin($data)) != $data Status: Open Type: Bug Package: *General Issues Operating System: Debian Linux PHP Version: 5.4.1RC1 Block user comment: N Private report: N New Comment: > The reason is simple: A padding can be either added on the left or on the right. E.g. "af52b" could be interpreted both as "0af52b" and as "af52b0". Why would af52b ever mean af52b0 ? That's like saying 15 could be interpreted as 150 sometimes. Previous Comments: ------------------------------------------------------------------------ [2012-04-08 15:25:52] nikic@php.net In my eyes hex2bin should not try to fix the corrupt data by padding it with zero. Instead it should throw a warning. The reason is simple: A padding can be either added on the left or on the right. E.g. "af52b" could be interpreted both as "0af52b" and as "af52b0". Both are valid interpretations, depending on the use case. Because of this I think a warning is more appropriate. It signals the user that the data is wrong. He can always easily fix it by adding a zero to either of the sides, whatever is more appropriate in his particular situation. Blindly adding the padding on the other hand will probably be quite unexpected. Especially when adding the 0 on the left side all the data will be shifted by 4 bits. This means that the whole data will be corrupted. All bytes will change. (Adding a padding on the right is less intrusive as it only changes one byte). ------------------------------------------------------------------------ [2012-04-08 13:20:35] krtek4+php at gmail dot com You are right, there was a bug in the patch I sent. I updated it on github. Thanks for the comment ! ------------------------------------------------------------------------ [2012-04-08 12:23:32] theanomaly dot is at gmail dot com @krtek4+php I didn't mean to step on any toes, honestly. I think your patch probably looks way cleaner than mine, but when I tried compiling your patch it did not work for me. The test didn't pass. var_dump(bin2hex(hex2bin(1))); // returned string(0) "" Maybe I didn't do it right, but that's the only reason I submitted another patch after I tested again on the PHP-5.4 branch. ------------------------------------------------------------------------ [2012-04-08 10:08:14] krtek4+php at gmail dot com If I could intervene, my patch does exactly the same thing without adding a new test for each iteration of the loop. Mine has only one modulo (%) outside of the loop and the new test is executed only once at the first pass assuming the string is a correct hexadecimal value. Like said in your last comment, the % operation can even be optimized with a '& 1' if needed. ------------------------------------------------------------------------ [2012-04-08 10:01:22] laruence@php.net @theanomaly as we talked, since Rasmus said it's okey, then I have no objection. 2 suggestions : 1. use oddlen & 1 instead of oddlen % 2 2. since you cal oddlen % 2 twice, so it's better if you can use a var to hold it and it's better for you to make a pull request by yourself, let me know if you need help on that :) ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=61660 -- Edit this bug report at https://bugs.php.net/bug.php?id=61660&edit=1