Question

For testing purposes I need strings such as:

"test\x00string"

I would like to loop over the control characters (00-1F) and generate the strings automatically so I don’t have to clutter my code with 31 lines like this but don’t know how to realize that in php.

Also for testing malformed utf I might want to insert other byte sequences into strings.

Answer 1

For certain characters there are predefined escape sequences, which can be used in double quotes:

$nullByte = "\0";

However, if you’re gonna loop, your best bet would be chr():

$string = '';

foreach (range( 0x00, 0x1F ) as $i)
{
    $string .= chr($i);
}

And as a one-liner:

$string = implode('', array_map('chr', range(0x00, 0x1F)));