CristalCaveGem » LustreC

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(*                                                                     *)

(*                                OCaml                                *)

(*                                                                     *)

(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)

(*                                                                     *)

(*  Copyright 1996 Institut National de Recherche en Informatique et   *)

(*  en Automatique.  All rights reserved.  This file is distributed    *)

(*  under the terms of the GNU Library General Public License, with    *)

(*  the special exception on linking described in file ../LICENSE.     *)

(*                                                                     *)

(***********************************************************************)

module type OrderedType =

  sig

    type t

    val compare: t -> t -> int

  end

module type S =

  sig

    type key

    type +'a t

    val empty: 'a t

    val is_empty: 'a t -> bool

    val mem:  key -> 'a t -> bool

    val add: key -> 'a -> 'a t -> 'a t

    val singleton: key -> 'a -> 'a t

    val remove: key -> 'a t -> 'a t

    val merge:

          (key -> 'a option -> 'b option -> 'c option) -> 'a t -> 'b t -> 'c t

    val compare: ('a -> 'a -> int) -> 'a t -> 'a t -> int

    val equal: ('a -> 'a -> bool) -> 'a t -> 'a t -> bool

    val iter: (key -> 'a -> unit) -> 'a t -> unit

    val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b

    val for_all: (key -> 'a -> bool) -> 'a t -> bool

    val exists: (key -> 'a -> bool) -> 'a t -> bool

    val filter: (key -> 'a -> bool) -> 'a t -> 'a t

    val partition: (key -> 'a -> bool) -> 'a t -> 'a t * 'a t

    val cardinal: 'a t -> int

    val bindings: 'a t -> (key * 'a) list

    val min_binding: 'a t -> (key * 'a)

    val max_binding: 'a t -> (key * 'a)

    val choose: 'a t -> (key * 'a)

    val split: key -> 'a t -> 'a t * 'a option * 'a t

    val find: key -> 'a t -> 'a

    val map: ('a -> 'b) -> 'a t -> 'b t

    val mapi: (key -> 'a -> 'b) -> 'a t -> 'b t

  end

module Make(Ord: OrderedType) = struct

    type key = Ord.t

    type 'a t =

        Empty

      | Node of 'a t * key * 'a * 'a t * int

    let height = function

        Empty -> 0

      | Node(_,_,_,_,h) -> h

    let create l x d r =

      let hl = height l and hr = height r in

      Node(l, x, d, r, (if hl >= hr then hl + 1 else hr + 1))

    let singleton x d = Node(Empty, x, d, Empty, 1)

    let bal l x d r =

      let hl = match l with Empty -> 0 | Node(_,_,_,_,h) -> h in

      let hr = match r with Empty -> 0 | Node(_,_,_,_,h) -> h in

      if hl > hr + 2 then begin

        match l with

          Empty -> invalid_arg "Map.bal"

        | Node(ll, lv, ld, lr, _) ->

            if height ll >= height lr then

              create ll lv ld (create lr x d r)

            else begin

              match lr with

                Empty -> invalid_arg "Map.bal"

              | Node(lrl, lrv, lrd, lrr, _)->

                  create (create ll lv ld lrl) lrv lrd (create lrr x d r)

            end

      end else if hr > hl + 2 then begin

        match r with

          Empty -> invalid_arg "Map.bal"

        | Node(rl, rv, rd, rr, _) ->

            if height rr >= height rl then

              create (create l x d rl) rv rd rr

            else begin

              match rl with

                Empty -> invalid_arg "Map.bal"

              | Node(rll, rlv, rld, rlr, _) ->

                  create (create l x d rll) rlv rld (create rlr rv rd rr)

            end

      end else

        Node(l, x, d, r, (if hl >= hr then hl + 1 else hr + 1))

    let empty = Empty

    let is_empty = function Empty -> true | _ -> false

    let rec add x data = function

        Empty ->

          Node(Empty, x, data, Empty, 1)

      | Node(l, v, d, r, h) ->

          let c = Ord.compare x v in

          if c = 0 then

            Node(l, x, data, r, h)

          else if c < 0 then

            bal (add x data l) v d r

          else

            bal l v d (add x data r)

    let rec find x = function

        Empty ->

          raise Not_found

      | Node(l, v, d, r, _) ->

          let c = Ord.compare x v in

          if c = 0 then d

          else find x (if c < 0 then l else r)

    let rec mem x = function

        Empty ->

          false

      | Node(l, v, d, r, _) ->

          let c = Ord.compare x v in

          c = 0 || mem x (if c < 0 then l else r)

    let rec min_binding = function

        Empty -> raise Not_found

      | Node(Empty, x, d, r, _) -> (x, d)

      | Node(l, x, d, r, _) -> min_binding l

    let rec max_binding = function

        Empty -> raise Not_found

      | Node(l, x, d, Empty, _) -> (x, d)

      | Node(l, x, d, r, _) -> max_binding r

    let rec remove_min_binding = function

        Empty -> invalid_arg "Map.remove_min_elt"

      | Node(Empty, x, d, r, _) -> r

      | Node(l, x, d, r, _) -> bal (remove_min_binding l) x d r

    let merge t1 t2 =

      match (t1, t2) with

        (Empty, t) -> t

      | (t, Empty) -> t

      | (_, _) ->

          let (x, d) = min_binding t2 in

          bal t1 x d (remove_min_binding t2)

    let rec remove x = function

        Empty ->

          Empty

      | Node(l, v, d, r, h) ->

          let c = Ord.compare x v in

          if c = 0 then

            merge l r

          else if c < 0 then

            bal (remove x l) v d r

          else

            bal l v d (remove x r)

    let rec iter f = function

        Empty -> ()

      | Node(l, v, d, r, _) ->

          iter f l; f v d; iter f r

    let rec map f = function

        Empty ->

          Empty

      | Node(l, v, d, r, h) ->

          let l' = map f l in

          let d' = f d in

          let r' = map f r in

          Node(l', v, d', r', h)

    let rec mapi f = function

        Empty ->

          Empty

      | Node(l, v, d, r, h) ->

          let l' = mapi f l in

          let d' = f v d in

          let r' = mapi f r in

          Node(l', v, d', r', h)

    let rec fold f m accu =

      match m with

        Empty -> accu

      | Node(l, v, d, r, _) ->

          fold f r (f v d (fold f l accu))

    let rec for_all p = function

        Empty -> true

      | Node(l, v, d, r, _) -> p v d && for_all p l && for_all p r

    let rec exists p = function

        Empty -> false

      | Node(l, v, d, r, _) -> p v d || exists p l || exists p r

    (* Beware: those two functions assume that the added k is *strictly*

       smaller (or bigger) than all the present keys in the tree; it

       does not test for equality with the current min (or max) key.

       Indeed, they are only used during the "join" operation which

       respects this precondition.

    *)

    let rec add_min_binding k v = function

      | Empty -> singleton k v

      | Node (l, x, d, r, h) ->

        bal (add_min_binding k v l) x d r

    let rec add_max_binding k v = function

      | Empty -> singleton k v

      | Node (l, x, d, r, h) ->

        bal l x d (add_max_binding k v r)

    (* Same as create and bal, but no assumptions are made on the

       relative heights of l and r. *)

    let rec join l v d r =

      match (l, r) with

        (Empty, _) -> add_min_binding v d r

      | (_, Empty) -> add_max_binding v d l

      | (Node(ll, lv, ld, lr, lh), Node(rl, rv, rd, rr, rh)) ->

          if lh > rh + 2 then bal ll lv ld (join lr v d r) else

          if rh > lh + 2 then bal (join l v d rl) rv rd rr else

          create l v d r

    (* Merge two trees l and r into one.

       All elements of l must precede the elements of r.

       No assumption on the heights of l and r. *)

    let concat t1 t2 =

      match (t1, t2) with

        (Empty, t) -> t

      | (t, Empty) -> t

      | (_, _) ->

          let (x, d) = min_binding t2 in

          join t1 x d (remove_min_binding t2)

    let concat_or_join t1 v d t2 =

      match d with

      | Some d -> join t1 v d t2

      | None -> concat t1 t2

    let rec split x = function

        Empty ->

          (Empty, None, Empty)

      | Node(l, v, d, r, _) ->

          let c = Ord.compare x v in

          if c = 0 then (l, Some d, r)

          else if c < 0 then

            let (ll, pres, rl) = split x l in (ll, pres, join rl v d r)

          else

            let (lr, pres, rr) = split x r in (join l v d lr, pres, rr)

    let rec merge f s1 s2 =

      match (s1, s2) with

        (Empty, Empty) -> Empty

      | (Node (l1, v1, d1, r1, h1), _) when h1 >= height s2 ->

          let (l2, d2, r2) = split v1 s2 in

          concat_or_join (merge f l1 l2) v1 (f v1 (Some d1) d2) (merge f r1 r2)

      | (_, Node (l2, v2, d2, r2, h2)) ->

          let (l1, d1, r1) = split v2 s1 in

          concat_or_join (merge f l1 l2) v2 (f v2 d1 (Some d2)) (merge f r1 r2)

      | _ ->

          assert false

    let rec filter p = function

        Empty -> Empty

      | Node(l, v, d, r, _) ->

          (* call [p] in the expected left-to-right order *)

          let l' = filter p l in

          let pvd = p v d in

          let r' = filter p r in

          if pvd then join l' v d r' else concat l' r'

    let rec partition p = function

        Empty -> (Empty, Empty)

      | Node(l, v, d, r, _) ->

          (* call [p] in the expected left-to-right order *)

          let (lt, lf) = partition p l in

          let pvd = p v d in

          let (rt, rf) = partition p r in

          if pvd

          then (join lt v d rt, concat lf rf)

          else (concat lt rt, join lf v d rf)

    type 'a enumeration = End | More of key * 'a * 'a t * 'a enumeration

    let rec cons_enum m e =

      match m with

        Empty -> e

      | Node(l, v, d, r, _) -> cons_enum l (More(v, d, r, e))

    let compare cmp m1 m2 =

      let rec compare_aux e1 e2 =

          match (e1, e2) with

          (End, End) -> 0

        | (End, _)  -> -1

        | (_, End) -> 1

        | (More(v1, d1, r1, e1), More(v2, d2, r2, e2)) ->

            let c = Ord.compare v1 v2 in

            if c <> 0 then c else

            let c = cmp d1 d2 in

            if c <> 0 then c else

            compare_aux (cons_enum r1 e1) (cons_enum r2 e2)

      in compare_aux (cons_enum m1 End) (cons_enum m2 End)

    let equal cmp m1 m2 =

      let rec equal_aux e1 e2 =

          match (e1, e2) with

          (End, End) -> true

        | (End, _)  -> false

        | (_, End) -> false

        | (More(v1, d1, r1, e1), More(v2, d2, r2, e2)) ->

            Ord.compare v1 v2 = 0 && cmp d1 d2 &&

            equal_aux (cons_enum r1 e1) (cons_enum r2 e2)

      in equal_aux (cons_enum m1 End) (cons_enum m2 End)

    let rec cardinal = function

        Empty -> 0

      | Node(l, _, _, r, _) -> cardinal l + 1 + cardinal r

    let rec bindings_aux accu = function

        Empty -> accu

      | Node(l, v, d, r, _) -> bindings_aux ((v, d) :: bindings_aux accu r) l

    let bindings s =

      bindings_aux [] s

    let choose = min_binding

end