Bug #61038 [Opn->Csd]: unpack("a5", "str\0\0") does not work as expected

Edit report at https://bugs.php.net/bug.php?id=61038&edit=1 ID: 61038 Updated by: cataphract@php.net Reported by: su dot hang at yahoo dot com Summary: unpack("a5", "str\0\0") does not work as expected -Status: Open +Status: Closed Type: Bug Package: *General Issues Operating System: Linux (3.0.0-15-generic) PHP Version: Irrelevant -Assigned To: +Assigned To: cataphract Block user comment: N Private report: N New Comment: Fixed in master only due to BC concerns. Thank you. Previous Comments: ------------------------------------------------------------------------ [2012-04-17 21:23:54] cataphract@php.net Automatic comment on behalf of googleguy@googleguy-virtualbox.(none) Revision: http://git.php.net/?p=php-src.git;a=commit;h=4968fa644b0849321e1761e52b8db15dd46f9b75 Log: Fixed bug #61038; "Z" and better behavior for unpack() ------------------------------------------------------------------------ [2012-02-13 09:50:28] su dot hang at yahoo dot com yes, that's right. "a", as in the spec, represents arbitrary binary string, with null-padding. so, if the specified unpack length is fixed, such as a constant number (like in "unpack('a10')"), then the unpacked string from "a" should have that length (unless, of course, if the input is insufficient). since "a" is arbitrary binary string, if it has several "\0"s at the end, php should not remove them as if it was a regular null-terminated string. ------------------------------------------------------------------------ [2012-02-13 08:39:00] cataphract@php.net I'm not sure I understand. Is the problem that 'a' (as opposed to 'A') on unpack should leave the string as is, as is the case with perl? ------------------------------------------------------------------------ [2012-02-10 16:53:54] su dot hang at yahoo dot com sorry, please use the test script instead of the subject. It is a bug because it is against the spec that "a" is an arbitrary binary string. If specified length is 5 then it should be null-padded at the end, rather than being truncated. try unpack('a5', "\x12\x34\x00\x56\x00"). at least, to be consistent, the result string should terminate at the first "\0", instead of the trailing one. btw, perl is handling it correctly. ------------------------------------------------------------------------ [2012-02-10 16:34:10] cataphract@php.net I don't see anything wrong here. unpack("a5", "foo\0\0") removes the NULL padding from the input string. The 5 specifies only the size of the input to consume: php > var_dump(unpack("a5", "foo\0")); PHP Warning: unpack(): Type a: not enough input, need 5, have 4 in php shell code on line 1 ------------------------------------------------------------------------ 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=61038 -- Edit this bug report at https://bugs.php.net/bug.php?id=61038&edit=1