Edit report at http://bugs.php.net/bug.php?id=52657&edit=1
ID: 52657
Comment by: giorgio dot liscio at email dot it
Reported by: marco dot weber at uni-trier dot de
Summary: create a spl_object_id function
Status: Open
Type: Feature/Change Request
Package: SPL related
Operating System: ANY
PHP Version: Irrelevant
Block user comment: N
New Comment:
i've experienced problems with uniqueness ofspl_object_hash
i think should be rebuilt with a better one algorithm
there is no need (i think) of another function, just fix
spl_object_hash
i think it is really important to fix
Previous Comments:
------------------------------------------------------------------------
[2010-08-20 17:38:19] marco dot weber at uni-trier dot de
i've forgotten to write down the test1 class:
class test1 {
public function __construct($s) { }
}
------------------------------------------------------------------------
[2010-08-20 17:34:25] marco dot weber at uni-trier dot de
Description:
------------
the problem with spl_object_hash is, that it is only unqiue for the
existing objects.
For a given Object:
class container {
protected $storage=array();
public function add(test1 $obj) {
if(!isset($this->storage[spl_object_hash($obj)])) {
$this->storage[spl_object_hash($obj)]=$obj;
}
}
}
This leads to a problem, that the add method receives the same hash in
to following cases:
CASE1:
$o=new container();
$o->add(new test1("lalala"));
$o->add(new test1("lololo")); // same hash, that's NOT ok!
CASE2:
$t=new test("lalala");
$o=new container();
$o->add($t);
$o->add($t); // same hash, that's ok!
Since there is nothing wrong, with the spl_object_hash() method, i
suggest to introduce a new spl_object_id() function. This could simply
return an (internal) uint32, that is attached to every object on its
creation. This counter gets incremented on every object that gets
created. :)
Test script:
---------------
// just with spl_object_hash :/
class container {
protected $storage=array();
public function add(test1 $obj) {
if(!isset($this->storage[spl_object_hash($obj)])) {
$this->storage[spl_object_hash($obj)]=$obj;
}
}
}
$o=new container();
$o->add(new test1("lalala")); // will be added
$o->add(new test1("lololo")); // not added - NOT as expected
$t=new test("lalala");
$o=new container();
$o->add($t); // will be added
$o->add($t); // not added - as expected
Expected result:
----------------
// with the new spl_object_id function :)
class container {
protected $storage=array();
public function add(test1 $obj) {
if(!isset($this->storage[spl_object_id($obj)])) {
$this->storage[spl_object_id($obj)]=$obj;
}
}
}
$o=new container();
$o->add(new test1("lalala")); // will be added
$o->add(new test1("lololo")); // will be added
$t=new test("lalala");
$o=new container();
$o->add($t); // will be added
$o->add($t); // not added
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/bug.php?id=52657&edit=1
