(* q1.ml - Don Yang (uguu.org)

   08/05/03
                                                                           *)

open String;;

let template = "P.bK .bEaE.";;
let data = "kfool#tlqog";;
let key = 3;;


let rec int_list_to_string lst k =
   match lst with
   a::b -> (make 1 (Char.chr (a lxor k)) ^ (int_list_to_string b k))
   | [] -> "";;

let rec string_to_int_list str =
   if str = ""
   then []
   else
      Char.code (get str 0) ::
      string_to_int_list (sub str 1 ((length str) - 1));;

let xor_string s k =
   int_list_to_string (string_to_int_list s) k;;

let rec remove_space str =
   if str = ""
   then str
   else
   (
      (let x = sub str 0 1 in if x = " " then "" else x) ^
      (remove_space (sub str 1 ((length str) - 1)))
   );;


let rec format_text template text =
   match template with
   x::y ->
      if x > 64 && x < 91 then
      (
         let x = x - 64 in
         (
            print_string (sub text 0 x);
            format_text y (sub text x ((length text) - x))
         )
      )
      else
      (
         if x > 96 && x < 123
         then print_string (make (x - 96) ' ')
         else print_newline ();
         format_text y text
      );
   | [] -> ();;


format_text
   (string_to_int_list (remove_space template))
   (remove_space ("header" ^ template ^ data ^ (xor_string data key)));;