Mine

<?php

class Eauth_Core {

        $db = NULL;

        function __construct()
        {
                $this->db = new Database();
        }

        function try_login($condition = array())
        {
                $this->db->select('*');
                $this->db->from('awp_users');
                $this->db->join('awp_roles', 'awp_roles.id = awp_users.role_id', 'LEFT');
                $this->db->where($condition);
                $this->db->where('validated', 1);

                $query = $this->db->get();

                if ($query->num_rows !== 1)
                {
                        return FALSE;
                }
                else
                {
                        $row = $query->row();

                        $userdata = array(
                                                'user_id' => $row->id,
                                                'authenticated' => TRUE
                                        );
                        $this->session->set($userdata);
                        return TRUE;
                }
        }


        function try_session_login()
        {
                if ($this->session->get('user_id'))
                {
                        $query = $this->db->query('SELECT COUNT(*) AS total FROM awp_users WHERE id = ' . $this->session->get('user_id'));
                        $row = $query->row();
                        if ($row->total != 1)
                        {
                                // Bad session - kill it
                                $this->logout();
                                return FALSE;
                        }
                        else
                        {
                                return TRUE;
                        }
                }
                else
                {
                        return FALSE;
                }
        }

        function logout()
        {
                $this->session->destroy();
        }

        function get_field($field = '')
        {
                $this->db->select($field);
                $query = $this->db->getwhere('awp_users', array('id'=>$this->session->get('user_id')), 1, 0);
                if ($query->num_rows() == 1)
                {
                        $row = $query->row();
                        return $row->$field;
                }
        }

        function get_role($role)
        {
                $this->db->select('awp_roles.name');
                $this->db->JOIN('awp_roles', 'awp_users.role_id = awp_roles.id');
                $query = $this->db->getwhere('awp_users', array('awp_users.id'=>$this->session->get('user_id')), 1, 0);
                if($query->num_rows() === 1)
                {
                        $row = $query->row();
                        if($row->name === $role)
                        {
                                return TRUE;
                        }
                        else
                        {
                                return FALSE;
                        }
                }
                else
                {
                        return FALSE;
                }
        }
}

?>