(** Key for hastables that contain tuples of integers encoded in a Zarith integer *)

include Z

type kind = 
| Kind_2
| Kind_3
| Kind_4
| Kind_6
| Kind_12


(** Build a Zkey from an array or 2, 3, 4, 6, or 12 integers *)
let of_int_array ~kind a = 
  let (<|) x a = 
    Z.logor (Z.shift_left x 64) a
  in
  let (<<) x a = 
    Int64.logor (Int64.shift_left x 10) (Int64.of_int a)
  in
  let (<+) x a = 
    Int64.logor (Int64.shift_left x 16) (Int64.of_int a)
  in
  match kind with
  | Kind_2 -> (Int64.of_int a.(0)) <+ a.(1) |> Z.of_int64
  | Kind_3 -> (Int64.of_int a.(0)) << a.(1) << a.(2) |> Z.of_int64
  | Kind_4 -> (Int64.of_int a.(0)) <+ a.(1) <+ a.(2) <+ a.(3) |> Z.of_int64
  | Kind_6 -> (Int64.of_int a.(0)) << a.(1) << a.(2) << a.(3) << a.(4) << a.(5)
        |> Z.of_int64
  | Kind_12 ->
    let a =
      (Int64.of_int a.(0)) << a.(1) << a.(2) << a.(3) << a.(4) << a.(5)
      |> Z.of_int64 
     and b = 
      (Int64.of_int a.(6)) << a.(7) << a.(8) << a.(9) << a.(10) << a.(11)
      |> Z.of_int64 
     in a <| b


(** Transform the Zkey into an int array *)
let to_int_array ~kind a = 
  match kind with
  | Kind_2  -> [| Z.to_int @@ Z.extract a  16 16 ;
                  Z.to_int @@ Z.extract a   0 16 |]
  | Kind_3  -> [| Z.to_int @@ Z.extract a  20 10 ;
                  Z.to_int @@ Z.extract a   10 10 ;
                  Z.to_int @@ Z.extract a   0 10 |]
  | Kind_4  -> [| Z.to_int @@ Z.extract a  48 16 ;
                  Z.to_int @@ Z.extract a  32 16 ;
                  Z.to_int @@ Z.extract a  16 16 ;
                  Z.to_int @@ Z.extract a   0 16 |]
  | Kind_6  -> [| Z.to_int @@ Z.extract a  50 10 ;
                  Z.to_int @@ Z.extract a  40 10 ;
                  Z.to_int @@ Z.extract a  30 10 ;
                  Z.to_int @@ Z.extract a  20 10 ;
                  Z.to_int @@ Z.extract a  10 10 ;
                  Z.to_int @@ Z.extract a   0 10 |]
  | Kind_12 -> [| Z.to_int @@ Z.extract a 114 10 ;
                  Z.to_int @@ Z.extract a 104 10 ;
                  Z.to_int @@ Z.extract a  94 10 ;
                  Z.to_int @@ Z.extract a  84 10 ;
                  Z.to_int @@ Z.extract a  74 10 ;
                  Z.to_int @@ Z.extract a  64 10 ;
                  Z.to_int @@ Z.extract a  50 10 ;
                  Z.to_int @@ Z.extract a  40 10 ;
                  Z.to_int @@ Z.extract a  30 10 ;
                  Z.to_int @@ Z.extract a  20 10 ;
                  Z.to_int @@ Z.extract a  10 10 ;
                  Z.to_int @@ Z.extract a   0 10 |]

let to_string ~kind a =
  "< " ^ ( Z.to_string a ) ^ " | " ^ (
  to_int_array kind a 
  |> Array.map string_of_int
  |> Array.to_list
  |> String.concat ", "
  ) ^ " >"


(*
let debug () = 
  let k2  = of_int_array Kind_2  [| 1 ; 2 |]
  and k3  = of_int_array Kind_3  [| 1 ; 2 ; 3 |]
  and k4  = of_int_array Kind_4  [| 1 ; 2 ; 3; 4 |]
  and k6  = of_int_array Kind_6  [| 1 ; 2 ; 3; 4 ; 5; 6|]
  and k12 = of_int_array Kind_12 [| 1 ; 2 ; 3; 4 ; 5; 6 ; 7 ; 8 ; 9 ; 10 ; 11; 12|]
  in
  print_endline @@ to_string Kind_2 k2 ;
  print_endline @@ to_string Kind_3 k3 ;
  print_endline @@ to_string Kind_4 k4 ;
  print_endline @@ to_string Kind_6 k6 ;
  print_endline @@ to_string Kind_12 k12
  

let () = debug ()
*)