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Posted by Andy Hassall on 05/28/07 17:53
On 28 May 2007 09:29:46 -0700, Darko <darko.maksimovic@gmail.com> wrote:
>On May 28, 6:02 pm, "farri...@gmail.com" <farri...@gmail.com> wrote:
>> On May 28, 10:40 am, gezerpunta <css...@gmail.com> wrote:
>>
>> > strlen does not return the correct value .I compared the filesize()
>> > and strlen byte size but they are not equal. I must find binary string
>> > length and it must be equal to filesize()
>>
>> http://us.php.net/manual/en/function.mb-strlen.php#72979
>>
>> Google searches ("php binary string length") come in handy...
>
>In PHP, like in C, the string ends with a zero-character, '\0', (char)
>0, null-terminator, null-byte or whatever you like to call it.
No, that's not the case - PHP strings are stored with both the length and the
data, unlike C strings that just has one pointer and uses a terminator. They're
"binary-safe" - NUL doesn't terminate the string.
See the definition of zvalue_value in zend.h; the string part has both a "char
*val" and "int len".
Problems would start if you're using the mbstring.func_overload, which changes
how strlen() and the other functions work, and does try and treat strings as
strings of characters in a specific encoding rather than a string of bytes.
This is not the normal PHP behaviour.
$ cat test.php
<?php
$x = chr(0) . chr(0) . "blah" . chr(0) . chr(0);
print strlen($x);
?>
$ php test.php
8
--
Andy Hassall :: andy@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool
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