test the risk of occurence of an uniqueid

test-id.php

<?php 

$a = array();

class IdProvider {

  private $n = array('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9');

public function createId() {
	$s = '';
	for ($i = 0; $i < 7; $i++) {
		$o = array_rand($this->n);
		$s .= $this->n[$o];
	}
	
	return $s;
}
}


$s = new IdProvider();
$collision = 0;


for ($i = 0; $i < 3000000; $i++) {
	$id = $s->createId();
	//echo 'Nouveau slug : '.$id."\n";
	if (isset($a[$id])) {
		$collision++;
		echo 'une collision '.$id."\n";
	} else {
		$a[$id] = $i;
	}
}


echo "fin du script : $collision collisions \n";