<?php

/**
 * This diff algorithm works with arrays or normal values
 * All elements in $one, not in $two are in diffed results
 * Elements in $two that are not in $one are discluded
 * @param mixed $one - to diff
 * @param mixed $two - to compare
 * @return see above
 *   If $one is array and $two is not, $one
 *   If $one is not array and $two is, $one
 *   If $one is not array and $two is not array and both match, NULL
 */
function recursive_diff_assoc($one, $two)
{
    $diff = array();

    if(is_array($one) && is_array($two))
    {
        foreach($one as $k1 => $v1)
        {
            if(!array_key_exists($k1, $two))
            {
                $diff[$k1] = $v1;
            }
            else
            {
                $pd = recursiveDiffAssoc($one[$k1], $two[$k1]);

                if($pd != null)
                {
                    $diff[$k1] = $pd;
                }
            }
        }
    }
    else if(!is_array($one) || !is_array($two))
    {
        if($one != $two)
        {
            return $one;
        }
        else
        {
            return null;
        }
    }

    return $diff;
}