Check if string is UTF-8

Have not tested it...

<?php
function check_utf8($str) {
   
$len = strlen($str);
    for(
$i = 0; $i < $len; $i++){
       
$c = ord($str[$i]);
        if (
$c > 128) {
            if ((
$c > 247)) return false;
            elseif (
$c > 239) $bytes = 4;
            elseif (
$c > 223) $bytes = 3;
            elseif (
$c > 191) $bytes = 2;
            else return
false;
            if ((
$i + $bytes) > $len) return false;
            while (
$bytes > 1) {
               
$i++;
               
$b = ord($str[$i]);
                if (
$b < 128 || $b > 191) return false;
               
$bytes--;
            }
        }
    }
    return
true;
}
// end of check_utf8
?>
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