wuhei

    /**
     * Quicksorting (with partition) implementation to sort SplFixedArray on a specific key, 
     * I could not find this and I needed this because I'm stuck on PHP5.6 at work -- 2023-05-04 wuhei
     *
     * @param $arr SplFixedArray, array to sort
     * @param $key mixed, array key to sort on
     * @param $desc bool if true, sort descending
     * @param $leftIndex int, left index of the array to sort, defaults to 0
     * @param $rightIndex int, right index of the array to sort, defaults to count($arr) - 1
     * @return mixed