Compatibility with PHP5 < 5.4.0

[alasjo]

I noticed when testing PHP AES File Encryption in PHP 5.3.1 that the creation of key failed (because hex2bin wasn't introduced until PHP 5.4.0). In the readme of this project it states compatibility with PHP5 so I set out to fulfill that statement.

I have added a function similar to the bin_* functions in the library that checks if hex2bin exists, otherwise using an alternative approach with pack from the PHP.net comment section.

Moreover, the mb_substr function seems to treat length of NULL as zero. I have added a check for NULL length and replace it with the mb_strlen of the string.

Tested and working in PHP 5.3.1.

[jonathangoncalves]

$len = strlen( **$str** ); for ( $i = 0; $i < $len; $i += 2 ) { $sbin .= pack( "H*", substr( $str, $i, 2 ) ); }

Why'd you use the "$str" variable? Shouldn't be "$string"?

[nbatteur]

yes Jonathan, it's true. And the good function is:
$len = strlen( $string ); for ( $i = 0; $i < $len; $i += 2 ) { $sbin .= chr( hexdec( $string{$i}.$string{( $i+1 )} ) ); }

[alasjo]

I missed the typo of $string, commited the correct variable name. Somewhat late...