UTF-8 validation in PHP without using preg_match()

Question

I need to validate some user input that is encoded in UTF-8. Many have recommended using the following code:

preg_match(\'/\\A(
     [\\x09\\x0A\\x0D\\x20-\\         


        

Answer 1

Here is a string-function based solution:

http://www.php.net/manual/en/function.mb-detect-encoding.php#85294

 128){
            if(($c >= 254)) return false;
            elseif($c >= 252) $bits=6;
            elseif($c >= 248) $bits=5;
            elseif($c >= 240) $bits=4;
            elseif($c >= 224) $bits=3;
            elseif($c >= 192) $bits=2;
            else return false;
            if(($i+$bits) > $len) return false;
            while($bits > 1){
                $i++;
                $b=ord($str[$i]);
                if($b < 128 || $b > 191) return false;
                $bits--;
            }
        }
    }
    return true;
}
?>