PHP Convert SimpleXML object to Array

public function simpleXMLToArray(SimpleXMLElement $xml,$attributesKey=null,$childrenKey=null,$valueKey=null){

    if($childrenKey && !is_string($childrenKey)){$childrenKey = '@children';}
    if($attributesKey && !is_string($attributesKey)){$attributesKey = '@attributes';}
    if($valueKey && !is_string($valueKey)){$valueKey = '@values';}

    $return = array();
    $name = $xml->getName();
    $_value = trim((string)$xml);
    if(!strlen($_value)){$_value = null;};

    if($_value!==null){
        if($valueKey){$return[$valueKey] = $_value;}
        else{$return = $_value;}
    }

    $children = array();
    $first = true;
    foreach($xml->children() as $elementName => $child){
        $value = $this->simpleXMLToArray($child,$attributesKey, $childrenKey,$valueKey);
        if(isset($children[$elementName])){
            if(is_array($children[$elementName])){
                if($first){
                    $temp = $children[$elementName];
                    unset($children[$elementName]);
                    $children[$elementName][] = $temp;
                    $first=false;
                }
                $children[$elementName][] = $value;
            }else{
                $children[$elementName] = array($children[$elementName],$value);
            }
        }
        else{
            $children[$elementName] = $value;
        }
    }
    if($children){
        if($childrenKey){$return[$childrenKey] = $children;}
        else{$return = array_merge($return,$children);}
    }

    $attributes = array();
    foreach($xml->attributes() as $name=>$value){
        $attributes[$name] = trim($value);
    }
    if($attributes){
        if($attributesKey){$return[$attributesKey] = $attributes;}
        else{$return = array_merge($return, $attributes);}
    }

    return $return;
}