Faster user role detection when passing requirements as a string

binary.php

<?php
class User {
    const ROLE_GUEST = 2;
    const ROLE_SHOPPER = 4;
    const ROLE_ADMIN = 8;
    const ROLE_SUPER = 16;
}

function has_role($role, $roles) {
    return $role & $roles;
}

$roles = User::ROLE_ADMIN | User::ROLE_SUPER;

var_dump( has_role(User::ROLE_GUEST, $roles)); // retruns 0
var_dump( has_role(User::ROLE_ADMIN, $roles)); // returns 8
var_dump( has_role(User::ROLE_ADMIN | User::ROLE_SUPER, $roles)); // returns 24

incremental.php

<?php
class User {
    const ROLE_GUEST = 1;
    const ROLE_SHOPPER = 2;
    const ROLE_ADMIN = 3;
    const ROLE_SUPER = 4;
}

function has_role($check, $roles) {
    $exploded_roles = explode('|', $roles);

    if(is_array($check)) {
        foreach ($check as $role) {
            if(in_array($role, $exploded_roles)) { return true; }
            return false;
        }
    }

    return in_array($check, $exploded_roles);
}

$roles = implode('|', [User::ROLE_ADMIN, User::ROLE_SUPER]);

var_dump( has_role(User::ROLE_GUEST, $roles)); // retruns false
var_dump( has_role(User::ROLE_ADMIN, $roles)); // retruns true
var_dump( has_role([User::ROLE_ADMIN, User::ROLE_SUPER], $roles)); // retruns true

Example

Note that in this example I'm trying to reduce the role information into a compact form so that it can be passed around a single scalar value. We are trying not to use an array or DB to pass the role information around the program.

Information

In this example, I'm using the bitwise operators do work the roles magic. These operators give you a great deal of flexibility. One of the biggest benefits is not just the speed and eloquence of the code but also that the return value is more informative.

http://php.net/manual/en/language.operators.bitwise.php