str_pad_unicode.php

<?

mb_internal_encoding('utf-8'); // @important

function str_pad_unicode($str, $pad_len, $pad_str = ' ', $dir = STR_PAD_RIGHT) {
    $str_len = mb_strlen($str);
    $pad_str_len = mb_strlen($pad_str);
    if (!$str_len && ($dir == STR_PAD_RIGHT || $dir == STR_PAD_LEFT)) {
        $str_len = 1; // @debug
    }
    if (!$pad_len || !$pad_str_len || $pad_len <= $str_len) {
        return $str;
    }

    $result = null;
    $repeat = ceil($str_len - $pad_str_len + $pad_len);
    if ($dir == STR_PAD_RIGHT) {
        $result = $str . str_repeat($pad_str, $repeat);
        $result = mb_substr($result, 0, $pad_len);
    } else if ($dir == STR_PAD_LEFT) {
        $result = str_repeat($pad_str, $repeat) . $str;
        $result = mb_substr($result, -$pad_len);
    } else if ($dir == STR_PAD_BOTH) {
        $length = ($pad_len - $str_len) / 2;
        $repeat = ceil($length / $pad_str_len);
        $result = mb_substr(str_repeat($pad_str, $repeat), 0, floor($length))
                    . $str
                       . mb_substr(str_repeat($pad_str, $repeat), 0, ceil($length));
    }

    return $result;
}