class salt
{
   /**
    * @var string $salt; the salt used for the password.
    */
   protected $salt;

   /**
    * @var string $password; the plain text password;
    */
   protected $password;

   public function __construct()
   {
      // declaring the variables.
      $this -> salt = $salt;
      $this -> password = $password = null;
   }

   public function generate_salt()
   {
      // the variable which determines the random salt.
      $this -> salt = substr(str_pad(dechex(mt_rand()), 8, '0', STR_PAD_LEFT ), -8 );

      // !return, easy. I think.
      if ($this -> salt != null)
      {
         return $this -> salt;
      }
   }

   /**
    * @desc; this function is a sub-function of make_salt. make_salt() relies on this function to provide output.
    */
   public function get_salt($username, $password)
   {
      // Old style MySQL query, your host should support it though.
      $this -> result = mysql_query("SELECT * FROM `login` WHERE username='".$username."' AND password='".$password."'");
      $this -> row = mysql_fetch_array($this -> result);

      if ($this -> row)
      {
         return $this -> row['salt'];
      }
      else
      {
         echo mysql_error();
      }
   }

   // the magic function!
   public function make_salt($username, $password)
   {
      // if there is no salt in the current user's table
      if (!self::get_salt($username,$password))
      {
         // generate a salt and insert it into the database
         $this -> salt = self::generate_salt();

         if ($this -> salt != null)
         {
            $this -> result = mysql_query("SELECT * FROM `login` WHERE username='".$username."' AND password='".$password."'");
            $this -> row = mysql_fetch_array($this -> result);

            // check if the user exists in the db, and then insert the salt.
            if ( $this -> row )
            {
               $this -> update_salt = mysql_query("UPDATE `login` SET salt='".$this -> salt."' WHERE username='".$username."' AND password='".$password."'");
               if (!$this -> update_salt)
                  echo mysql_error();
            }
            else
            {
               echo mysql_error();
               die('Unable to find the specified user.. maybe he/she does not exist?!');
            }
         }
         else
            // if the salt is null, then die with this message. you should never see this though. last resort exit.
            die('Salt is null?!');
      }
      else
      {
         // if the user has a salt, then grab it and hash the provided password to obtain the final salted password.
         if (self::get_salt($username,$password))
         {
            $this -> user_salt = self::get_salt($username,$password);

            $this -> salted_password = sha1($this->user_salt.$password);
            return $this -> salted_password;
         }
         else
         {
            die('Unable to retrieve the salt for this user.');
         }
      }
   }
}