Sample class for bitmasked permissions

permissions.php

<?php
/**
 * @author Arlo Carreon
 * 
 */
class Permissions {
    
    // Bitmasks
    const REPORTS       = 1;
    const QUIZES        = 2;
    const CONTROL_PANEL = 4;
    const GROUPS        = 8;
    const USERS         = 16;
    const DEPARTMENTS   = 32;

    // User role
    private static $_role = null;

    // User Role Definitions
    private static $_allRoles = NULL;

    public static function setRole( $role ) {
        

       self::$_allRoles =  array(
            "Learner"     => self::QUIZES ,
            "Reporter"    => self::REPORTS + self::GROUPS,
            "Trainer"     => self::CONTROL_PANEL + self::GROUPS + self::USERS ,
            "Administrator" => self::CONTROL_PANEL + self::QUIZES +  self::USERS + self::GROUPS +  self::DEPARTMENTS
        );

       self::$_role = array_key_exists($role,self::$_allRoles) ? $role:"learner";
    }


    /**
     * Validates a permission against the user
     * @param  const  $permission A value from the bitmasks
     * @return boolean             Whether the user has permission to given permission
     */
    public static function has( $permission ) {
        return (self::$_allRoles[self::$_role] & $permission);
    }

}