Json & Array from XML in 3 lines:

$xml = simplexml_load_string($xml_string);
$json = json_encode(array = json_decode($json,TRUE);

Here is my variant of JSON to XML conversion. I get an array from JSON using json_decode() function:

$array = json_decode ($someJsonString, true);

Then I convert the array to XML with my arrayToXml() function:

$xml = new SimpleXMLElement('<root/>');
$this->arrayToXml($array, $xml);

Here is my arrayToXml() function:

/**
 * Convert an array to XML
 * @param array $array
 * @param SimpleXMLElement $xml
 */
function arrayToXml($array, &$xml){
    foreach ($array as $key => $value) {
        if(is_int($key)){
            $key = "e";
        }
        if(is_array($value)){
            $label = $xml->addChild($key);
            $this->arrayToXml($value, $label);
        }
        else {
            $xml->addChild($key, $value);
        }
    }
}