is_serialized.php

<?php
error_reporting(E_ALL);

$data = array();
$data[] = serialize( array( 1, 2, 3, array( 'een', 'twee', 'tree' ) ) );
$data[] = 'a:4:{i:0;i:1;i:1;i:2;i:2;i:3;i:3;a:3:{i:0;s:3:"een";i:1;s:4:"twee";i:2;s:4:"tree";}}';
$data[] = 'a:{i0;i1;i1;i2;i2;i3;i3;a:{i0;s:"een";i1;s:"twee";i2;s:"tree";}}';
$data[] = serialize( 'blah' );
$data[] = 'blah';

var_dump( $data );

$unserialized_data = array();
$unserialized_data = array_map( 'is_serialized', $data );

var_dump( $unserialized_data );

var_dump( is_serialized( $data[0], TRUE ) );
var_dump( is_serialized( $data[2], TRUE ) );
	
function is_serialized( $object, $just_test = FALSE ){
	$unserial = @unserialize( $object );
	
	if( ! $just_test ){
		return $unserial ? $unserial : 'No serialized data'; 
	} else {
		return (bool) $unserial;
	}
}