lubuntu.me/plugins/all-in-one-wp-security-and-firewall/classes/wp-security-config.php

<?php
class AIOWPSecurity_Config{
    var $configs;
    var $message_stack;
    static $_this;
    
    function __construct(){
        $this->message_stack = new stdClass();
    }

    function load_config(){	
	$this->configs = get_option('aio_wp_security_configs');
    }
	
    function get_value($key){
    	return isset($this->configs[$key])?$this->configs[$key] : '';    	
    }
    
    function set_value($key, $value){
    	$this->configs[$key] = $value;
    }
    
    function add_value($key, $value){
        if(!is_array($this->configs)){$this->configs = array();}

    	if (array_key_exists($key, $this->configs)){
            //Don't update the value for this key
    	}
    	else{//It is safe to update the value for this key
            $this->configs[$key] = $value;
    	}    	
    }

    function save_config(){
    	update_option('aio_wp_security_configs', $this->configs);
    }

    function get_stacked_message($key){
        if(isset($this->message_stack->{$key}))
            return $this->message_stack->{$key};
        return "";
    }
    
    function set_stacked_message($key,$value){
        $this->message_stack->{$key} = $value;
    }
    
    static function get_instance(){
    	if(empty(self::$_this)){
            self::$_this = new AIOWPSecurity_Config();
            self::$_this->load_config();
            return self::$_this;
    	}
    	return self::$_this;
    }
}