Mixed object / array iteration - php

Question

I need a way to iterate any array or object ($this->_data).
The current draft is following:
class values implements \Iterator{
private $_data = null; // array or object
private $_keys = [];
private $_key = false;
// ------------ \Iterator implementation
public function current(){
return $this->get($this->_key);
}
public function key(){
return $this->_key;
}
public function next(){
$this->_key = \next($this->_keys);
}
public function rewind(){
$this->_keys = [];
foreach ($this->_data as $k => $v){
$this->_keys[] = $k;
}
$this->_key = \reset($this->_keys);
}
public function valid(){
if (false === $this->_key){
return false;
}
return $this->has($this->_key);
}
}
The problem is that i do not want to hold additional array for keys.
May be there are some better way to iterate keys of an object avoiding additional abject/array creation for this purpose?
(External iterator is not an option because i do not want extra object creation in a foreach loops)
Example of mixed usage with native myClass::methods and wrapper's values::methods
class myClass{
var $x = 'x';
var $y = 'y';
public function hello(){
echo 'Hello, '.$this->x;
}
}
$a = new myClass();
$values = new values($a);
foreach ($values as $k => $v){
$values[$k] = $v.' modified';
}
$a->hello();
Additional notes:
values instance can be reused (by replacing $this->_data)
usage of this class can be very intensive (from 100 to over 100000 different objects/arrays passed)
values can be used and/or changed outside of values wrapper (see example above)

Answer 1

While it is possible to implement Iterator on your own in a way that you don't need to store $keys separately (I can show if you want) you can just use or extend the class ArrayObject. It looks like it perfectly fits your needs.
Check this example:
$a = new ArrayObject(array(
'a' => 'foo',
'b' => 'bar'
));
foreach($a as $k => $v) {
var_dump($k, $v);
}
Output:
string(1) "a"
string(3) "foo"
string(1) "b"
string(3) "bar"

Answer 2

For PHP 5.5.0+
Well, it actually fails, because it will create Generator instance at every call
class values implements IteratorAggregate{
private $_data = null; // array or object
public function __construct($data = null){
$this->_data = $data;
}
private static function g($data){
foreach ($data as $k => $v){
yield $k => $v;
}
}
public function getIterator(){
return self::g($this->_data);
}
}
Wish some alternative for php 5.4