PHP code wechat, official account and enterprise wechat send emoticons [u+1f449]

Add calling method

function utf8_bytes($cp) {
    if ($cp > 0x10000){
        return	chr(0xF0 | (($cp & 0x1C0000) >> 18)).
            chr(0x80 | (($cp & 0x3F000) >> 12)).
            chr(0x80 | (($cp & 0xFC0) >> 6)).
            chr(0x80 | ($cp & 0x3F));
    }else if ($cp > 0x800){
        return	chr(0xE0 | (($cp & 0xF000) >> 12)).
            chr(0x80 | (($cp & 0xFC0) >> 6)).
            chr(0x80 | ($cp & 0x3F));
    }else if ($cp > 0x80){
        return	chr(0xC0 | (($cp & 0x7C0) >> 6)).
            chr(0x80 | ($cp & 0x3F));
    }else{
        return chr($cp);
    }
}

  Convert expression

$content['conten'] Content sent for

$content['content'] = htmlspecialchars_decode($content['content']);
        preg_match_all('/\[U\+(\\w{4,})\]/i', $content['content'], $matchArray);
        if(!empty($matchArray[1])) {
            foreach ($matchArray[1] as $emojiUSB) {
                $content['content'] = str_ireplace("[U+{$emojiUSB}]", utf8_bytes(hexdec($emojiUSB)), $content['content']);
            }
        }