Print Unicode characters PHP

Question

I have a database which stores video game names with Unicode characters but I can't figure out how to properly escape these Unicode characters when printing them to an HTML response.

For instance, when I print all games with the name like Uncharted, I get this:

Uncharted: Drake's Fortuneâ„¢
Uncharted 2: Among Thievesâ„¢
Uncharted 3: Drake's Deceptionâ„¢

but it should display this:

Uncharted: Drake's Fortune™
Uncharted 2: Among Thieves™
Uncharted 3: Drake's Deception™

I ran a quick JavaScript escape function to see which Unicode character the ™ is and found that it's \u2122.

I don't have a problem fully escaping every character in the string if I can get the ™ character to display correctly. My guess is to somehow find the hex representation of each character in the string and have PHP render the Unicode characters like this:

print "&#x2122";

Please guide me through the best approach for Unicode escaping a string for being HTML friendly. I've done something similar for JavaScript a while back, but JavaScript has a built in function for escape and unescape.

I'm not aware of any PHP functions of similar functionality however. I have read about the ord function, but it just returns the ASCII character code for a given character, hence the improper display of the ™ or the ™. I would like this function to be versatile enough to apply to any string containing valid Unicode characters.

Answer 1

// PHP 7.0
var_dump(
    IntlChar::chr(0x2122),
    IntlChar::chr(0x1F638)
);

var_dump(
    utf8_chr(0x2122),
    utf8_chr(0x1F638)
);

function utf8_chr($cp) {

    if (!is_int($cp)) {
        exit("$cp is not integer\n");
    }

    // UTF-8 prohibits characters between U+D800 and U+DFFF
    // https://tools.ietf.org/html/rfc3629#section-3
    //
    // Q: Are there any 16-bit values that are invalid?
    // http://unicode.org/faq/utf_bom.html#utf16-7

    if ($cp < 0 || (0xD7FF < $cp && $cp < 0xE000) || 0x10FFFF < $cp) {
        exit("$cp is out of range\n");
    }

    if ($cp < 0x10000) {
        return json_decode('"\u'.bin2hex(pack('n', $cp)).'"');
    }

    // Q: Isn’t there a simpler way to do this?
    // http://unicode.org/faq/utf_bom.html#utf16-4
    $lead = 0xD800 - (0x10000 >> 10) + ($cp >> 10);
    $trail = 0xDC00 + ($cp & 0x3FF);

    return json_decode('"\u'.bin2hex(pack('n', $lead)).'\u'.bin2hex(pack('n', $trail)).'"');
}

Answer 2

I spent a lot of time trying to find the better way to just print the equivalent char of an unicode code, and the methods I found didn't work or it just were very complicated.

This said, JSON is able to represent unicode characters using the syntax "\u[unicode_code]", then:

echo json_decode('"\u00e1"'); 

Will print the equivalent unicode char, in this case: á.

P.D. Note the simple and the double quotes. If you don't put both it won't work.