Код символа → UTF-8

gistfile1.aw

<?php
function codeToUtf8($code) {
    $code = (int)$code;
    if ($code < 0x80) return chr($code);
    if ($code < 0x800) return chr(0xC0 + (($code >> 6) & 0x1F)) .
            chr(0x80 + ($code & 0x3F));
    if ($code < 0x10000) return chr(0xE0 + (($code >> 12) & 0x0F)) .
            chr(0x80 + (($code >> 6) & 0x3F)) .
            chr(0x80 + ($code & 0x3F));
    if ($code < 0x200000) return chr(0xF0 + (($code >> 18) & 0x07)) .
            chr(0x80 + (($code >> 12) & 0x3F)) .
            chr(0x80 + (($code >> 6) & 0x3F)) .
            chr(0x80 + ($code & 0x3F));
    return '?';
}