spl_classes
Note that the contents (properties) of the object are NOT hashed by the function, merely its internal handle and handler table pointer. This is sufficient to guarantee that any two objects simultaneously co-residing in memory will have different hashes. Uniqueness is not guaranteed between objects that did not reside in memory simultaneously, for example:
var_dump(spl_object_hash(new stdClass()), spl_object_hash(new stdClass()));
Running this alone will usually generate the same hashes, since PHP reuses the internal handle for the first stdClass after it has been dereferenced and destroyed when it creates the second stdClass.
spl_object_hash
(PHP 5 >= 5.2.0)
spl_object_hash — Retourne l'identifiant de hashage pour un objet donné
Description
string spl_object_hash
( object
$obj
)Cette fonction retourne un identifiant unique pour l'objet. Cet identifiant peut être utilisé comme clé de hashage pour stocker les objets ou pour les identifier.
Liste de paramètres
-
object -
N'importe quel objet.
Valeurs de retour
Une chaîne de caractères unique pour chaque élément existant dans l'objet et sera toujours identique pour chaque objet.
Exemples
Exemple #1 Exemple avec spl_object_hash()
<?php
$id = spl_object_hash($object);
$storage[$id] = $object;
?>
Notes
Note:
Lorsqu'un objet est détruit, son identifiant de hashage pourra être réutilisé pour d'autres objets.
add a note
User Contributed Notes
spl_object_hash - [3 notes]
planetbeing ¶
5 years ago
Rafael M. Salvioni ¶
4 years ago
The follow function is a implementation of the PHP´s function spl_object_hash(), unavailable in versions less 5.2.0.
But, the algorithm of this function is different of the original PHP´s function.
(Sorry... my english is very bad...)
<?php
if (!function_exists('spl_object_hash')) {
/**
* Returns the hash of the unique identifier for the object.
*
* @param object $object Object
* @author Rafael M. Salvioni
* @return string
*/
function spl_object_hash($object)
{
if (is_object($object)) {
ob_start(); var_dump($object); $dump = ob_get_contents(); ob_end_clean();
if (preg_match('/^object\(([a-z0-9_]+)\)\#(\d)+/i', $dump, $match)) {
return md5($match[1] . $match[2]);
}
}
trigger_error(__FUNCTION__ . "() expects parameter 1 to be object", E_USER_WARNING);
return null;
}
}
?>
mjs at beebo dot org ¶
8 days ago
Note that given two different objects spl_object_hash() can return values that look very similar, and in fact both the most significant *and* least significant digits are likely to be identical! e.g. "000000003cc56d770000000007fa48c5" and "000000003cc56d0d0000000007fa48c5".
Therefore (especially if using this function for debugging), you may wish to pass the hash into a cryptographic hash function like md5() to get to facilitate visual comparisons, and make it more likely that the first few or last few digits are unique.
md5("000000003cc56d770000000007fa48c5") -> "619a799747d348fa1caf181a72b65d9f"
md5("000000003cc56d0d0000000007fa48c5") -> "ae964bc912281e7804fe5a88b4546cb2"