UTF-8 to Unicode Code Points

Question

Is there a function that will change UTF-8 to Unicode leaving non special characters as normal letters and numbers?

ie the German word "tchüß" would be rendered as something like "tch\20AC\21AC" (please note that I am making the Unicode codes up).

EDIT: I am experimenting with the following function, but although this one works well with ASCII 32-127, it seems to fail for double byte chars:

function strToHex ($string)
{
    $hex = '';
    for ($i = 0; $i < mb_strlen ($string, "utf-8"); $i++)
    {
        $id = ord (mb_substr ($string, $i, 1, "utf-8"));
        $hex .= ($id <= 128) ? mb_substr ($string, $i, 1, "utf-8") : "&#" . $id . ";";
}

    return ($hex);
}

Any ideas?

EDIT 2: Found solution: The PHP ord() function does not work for double byte chars. Use instead: http://nl.php.net/manual/en/function.ord.php#78032

Answer 1

I had a problem when i need to convert string (utf-8 in default) with cyrilic to entities partly - only cyrilic. Finaly i need to get JSON-like result, like this:

<li class="my_class">City - Mocsow (Москва)</li>

to this:

<li class=\"my_class\">City - Mocsow (\u041c\u043e\u0441\u043a\u0432\u0430)<\/li>

So, i`ve got a compex (mix of subj. author and Nus) solution:

function strToHex($string){
    $enc="utf-8";
    $hex = '';
    for ($i = 0; $i < mb_strlen ($string, $enc); $i++){
        $id = ord (mb_substr ($string, $i, 1, $enc));
        $hex .= ($id <= 128) ? mb_substr ($string, $i, 1, $enc) : toCodePoint(mb_substr ($string, $i, 1, $enc), $enc);
    }
    return $hex;
}
function toCodePoint($string, $encoding){
    $utf32  = mb_convert_encoding( $string, 'UTF-32', $encoding );
    $length = mb_strlen( $utf32, 'UTF-32' );
    $result = Array();
    for( $i = 0; $i < $length; ++$i )$result[] = "\u".substr(bin2hex( mb_substr( $utf32, $i, 1, 'UTF-32' ) ), 4,8);
    return implode("", $result);
}
$output=strToHex(
    str_replace( // this is for json compatible
        array("\"", "\n", "\r", "\t", "/"),
        array('\"', '\n', "", " ", "\/"),
        $text
    )
);
echo $output;

It tested on php 5.2.17 :)

Answer 2

For a readable-form I would go with JSON. It's not required to escape non-ASCII characters in JSON, but PHP does:

echo json_encode("tchüß");

"tch\u00fc\u00df"