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+(*
+ Cours "Sémantique et Application à la Vérification de programmes"
+
+ Antoine Miné 2014
+ Ecole normale supérieure, Paris, France / CNRS / INRIA
+*)
+
+(*
+ This file is derived from the map.ml file from the OCaml distribution.
+ Changes are marked with the [AM] symbol.
+ Based on rev. 10468 2010-05-25 13:29:43Z
+
+ Original copyright follows.
+*)
+
+(***********************************************************************)
+(* *)
+(* Objective Caml *)
+(* *)
+(* 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
+
+
+ (* [AM] additions by Antoine Mine' *)
+
+ val of_list: (key * 'a) list -> 'a t
+
+ val map2: (key -> 'a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
+ val iter2: (key -> 'a -> 'b -> unit) -> 'a t -> 'b t -> unit
+ val fold2: (key -> 'a -> 'b -> 'c -> 'c) -> 'a t -> 'b t -> 'c -> 'c
+ val for_all2: (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
+ val exists2: (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
+
+ val map2z: (key -> 'a -> 'a -> 'a) -> 'a t -> 'a t -> 'a t
+ val iter2z: (key -> 'a -> 'a -> unit) -> 'a t -> 'a t -> unit
+ val fold2z: (key -> 'a -> 'a -> 'b -> 'b) -> 'a t -> 'a t -> 'b -> 'b
+ val for_all2z: (key -> 'a -> 'a -> bool) -> 'a t -> 'a t -> bool
+ val exists2z: (key -> 'a -> 'a -> bool) -> 'a t -> 'a t -> bool
+
+ val map2o: (key -> 'a -> 'c) -> (key -> 'b -> 'c) -> (key -> 'a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
+ val iter2o: (key -> 'a -> unit) -> (key -> 'b -> unit) -> (key -> 'a -> 'b -> unit) -> 'a t -> 'b t -> unit
+ val fold2o: (key -> 'a -> 'c -> 'c) -> (key -> 'b -> 'c -> 'c) -> (key -> 'a -> 'b -> 'c -> 'c) -> 'a t -> 'b t -> 'c -> 'c
+ val for_all2o: (key -> 'a -> bool) -> (key -> 'b -> bool) -> (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
+ val exists2o: (key -> 'a -> bool) -> (key -> 'b -> bool) -> (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
+
+ val map2zo: (key -> 'a -> 'a) -> (key -> 'a -> 'a) -> (key -> 'a -> 'a -> 'a) -> 'a t -> 'a t -> 'a t
+ val iter2zo: (key -> 'a -> unit) -> (key -> 'a -> unit) -> (key -> 'a -> 'a -> unit) -> 'a t -> 'a t -> unit
+ val fold2zo: (key -> 'a -> 'b -> 'b) -> (key -> 'a -> 'b -> 'b) -> (key -> 'a -> 'a -> 'b -> 'b) -> 'a t -> 'a t -> 'b -> 'b
+ val for_all2zo: (key -> 'a -> bool) -> (key -> 'a -> bool) -> (key -> 'a -> 'a -> bool) -> 'a t -> 'a t -> bool
+ val exists2zo: (key -> 'a -> bool) -> (key -> 'a -> bool) -> (key -> 'a -> 'a -> bool) -> 'a t -> 'a t -> bool
+
+ val map_slice: (key -> 'a -> 'a) -> 'a t -> key -> key -> 'a t
+ val iter_slice: (key -> 'a -> unit) -> 'a t -> key -> key -> unit
+ val fold_slice: (key -> 'a -> 'b -> 'b) -> 'a t -> key -> key -> 'b -> 'b
+ val for_all_slice: (key -> 'a -> bool) -> 'a t -> key -> key -> bool
+ val exists_slice: (key -> 'a -> bool) -> 'a t -> key -> key -> bool
+
+ val key_equal: 'a t -> 'a t -> bool
+ val key_subset: 'a t -> 'a t -> bool
+
+ val find_greater: key -> 'a t -> key * 'a
+ val find_less: key -> 'a t -> key * 'a
+ val find_greater_equal: key -> 'a t -> key * 'a
+ val find_less_equal: key -> 'a t -> key * 'a
+
+ 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 "Mapext.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 "Mapext.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 "Mapext.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 "Mapext.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 "Mapext.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))
+
+ (* [AM] changed to call p in the key order *)
+ let rec for_all p = function
+ Empty -> true
+ | Node(l, v, d, r, _) -> for_all p l && p v d && for_all p r
+
+ (* [AM] changed to call p in the key order *)
+ let rec exists p = function
+ Empty -> false
+ | Node(l, v, d, r, _) -> exists p l || p v d || exists p r
+
+ (* [AM] changed to call p in the key order *)
+ let filter p s =
+ fold (fun k d a -> if p k d then add k d a else a) s Empty
+
+ let partition p s =
+ let rec part (t, f as accu) = function
+ | Empty -> accu
+ | Node(l, v, d, r, _) ->
+ part (part (if p v d then (add v d t, f) else (t, add v d f)) l) r in
+ part (Empty, Empty) s
+
+ (* 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 v d r
+ | (_, Empty) -> add 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
+
+ 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
+
+
+
+ (* [AM] additions by Antoine Mine' *)
+ (* ******************************* *)
+
+
+ let of_list l =
+ List.fold_left (fun acc (k,x) -> add k x acc) empty l
+
+
+ (* similar to split, but returns unbalanced trees *)
+ let rec cut k = function
+ Empty -> Empty,None,Empty
+ | Node (l1,k1,d1,r1,h1) ->
+ let c = Ord.compare k k1 in
+ if c < 0 then
+ let l2,d2,r2 = cut k l1 in (l2,d2,Node (r2,k1,d1,r1,h1))
+ else if c > 0 then
+ let l2,d2,r2 = cut k r1 in (Node (l1,k1,d1,l2,h1),d2,r2)
+ else (l1,Some d1,r1)
+
+
+ (* binary operations that fail on maps with different keys *)
+
+ (* functions are called in increasing key order *)
+
+ let rec map2 f m1 m2 =
+ match m1 with
+ | Empty -> if m2 = Empty then Empty else invalid_arg "Mapext.map2"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ Node (map2 f l1 l2, k, f k d1 d2, map2 f r1 r2, h1)
+ | _, None, _ -> invalid_arg "Mapext.map2"
+
+ let rec iter2 f m1 m2 =
+ match m1 with
+ | Empty -> if m2 = Empty then () else invalid_arg "Mapext.iter2"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 -> iter2 f l1 l2; f k d1 d2; iter2 f r1 r2
+ | _, None, _ -> invalid_arg "Mapext.iter2"
+
+ let rec fold2 f m1 m2 acc =
+ match m1 with
+ | Empty -> if m2 = Empty then acc else invalid_arg "Mapext.fold2"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ fold2 f r1 r2 (f k d1 d2 (fold2 f l1 l2 acc))
+ | _, None, _ -> invalid_arg "Mapext.fold2"
+
+ let rec for_all2 f m1 m2 =
+ match m1 with
+ | Empty -> if m2 = Empty then true else invalid_arg "Mapext.for_all2"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ for_all2 f l1 l2 && f k d1 d2 && for_all2 f r1 r2
+ | _, None, _ -> invalid_arg "Mapext.for_all2"
+
+ let rec exists2 f m1 m2 =
+ match m1 with
+ | Empty -> if m2 = Empty then false else invalid_arg "Mapext.exists2"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ exists2 f l1 l2 || f k d1 d2 || exists2 f r1 r2
+ | _, None, _ -> invalid_arg "Mapext.exists2"
+
+
+ (* as above, but ignore physically equal subtrees
+ - for map, assumes: f k d d = d
+ - for iter, assumes: f k d d has no effect
+ - for fold, assumes: k f d d acc = acc
+ - for for_all, assumes: f k d d = true
+ - for exists, assumes: f k d d = false
+ *)
+
+ let rec map2z f m1 m2 =
+ if m1 == m2 then m1 else
+ match m1 with
+ | Empty -> if m2 = Empty then Empty else invalid_arg "Mapext.map2z"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ let d = if d1 == d2 then d1 else f k d1 d2 in
+ Node (map2z f l1 l2, k, d, map2z f r1 r2, h1)
+ | _, None, _ -> invalid_arg "Mapext.map2z"
+
+ let rec iter2z f m1 m2 =
+ if m1 == m2 then () else
+ match m1 with
+ | Empty -> if m2 = Empty then () else invalid_arg "Mapext.iter2z"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ iter2z f l1 l2; (if d1 != d2 then f k d1 d2); iter2z f r1 r2
+ | _, None, _ -> invalid_arg "Mapext.iter2z"
+
+ let rec fold2z f m1 m2 acc =
+ if m1 == m2 then acc else
+ match m1 with
+ | Empty -> if m2 = Empty then acc else invalid_arg "Mapext.fold2z"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ let acc = fold2z f l1 l2 acc in
+ let acc = if d1 == d2 then acc else f k d1 d2 acc in
+ fold2z f r1 r2 acc
+ | _, None, _ -> invalid_arg "Mapext.fold2z"
+
+ let rec for_all2z f m1 m2 =
+ (m1 == m2) ||
+ (match m1 with
+ | Empty -> if m2 = Empty then true else invalid_arg "Mapext.for_all2z"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ (for_all2z f l1 l2) &&
+ (d1 == d2 || f k d1 d2) &&
+ (for_all2z f r1 r2)
+ | _, None, _ -> invalid_arg "Mapext.for_all2z"
+ )
+
+ let rec exists2z f m1 m2 =
+ (m1 != m2) &&
+ (match m1 with
+ | Empty -> if m2 = Empty then false else invalid_arg "Mapext.exists2z"
+ | Node (l1,k,d1,r1,h1) ->
+ match cut k m2 with
+ | l2, Some d2, r2 ->
+ (exists2z f l1 l2) ||
+ (d1 != d2 && f k d1 d2) ||
+ (exists2z f r1 r2)
+ | _, None, _ -> invalid_arg "Mapext.exists2z"
+ )
+
+
+ (* as above, but allow maps with different keys *)
+
+ let rec map2o f1 f2 f m1 m2 =
+ match m1 with
+ | Empty -> mapi f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ let l = map2o f1 f2 f l1 l2 in
+ let d = match d2 with None -> f1 k d1 | Some d2 -> f k d1 d2 in
+ let r = map2o f1 f2 f r1 r2 in
+ join l k d r
+
+ let rec iter2o f1 f2 f m1 m2 =
+ match m1 with
+ | Empty -> iter f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ iter2o f1 f2 f l1 l2;
+ (match d2 with None -> f1 k d1 | Some d2 -> f k d1 d2);
+ iter2o f1 f2 f r1 r2
+
+ let rec fold2o f1 f2 f m1 m2 acc =
+ match m1 with
+ | Empty -> fold f2 m2 acc
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ let acc = fold2o f1 f2 f l1 l2 acc in
+ let acc = match d2 with
+ | None -> f1 k d1 acc | Some d2 -> f k d1 d2 acc
+ in
+ fold2o f1 f2 f r1 r2 acc
+
+ let rec for_all2o f1 f2 f m1 m2 =
+ match m1 with
+ | Empty -> for_all f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ (for_all2o f1 f2 f l1 l2) &&
+ (match d2 with None -> f1 k d1 | Some d2 -> f k d1 d2) &&
+ (for_all2o f1 f2 f r1 r2)
+
+ let rec exists2o f1 f2 f m1 m2 =
+ match m1 with
+ | Empty -> exists f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ (exists2o f1 f2 f l1 l2) ||
+ (match d2 with None -> f1 k d1 | Some d2 -> f k d1 d2) ||
+ (exists2o f1 f2 f r1 r2)
+
+
+ (* all together now *)
+
+ let rec map2zo f1 f2 f m1 m2 =
+ if m1 == m2 then m1 else
+ match m1 with
+ | Empty -> mapi f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ let l = map2zo f1 f2 f l1 l2 in
+ let d = match d2 with
+ | None -> f1 k d1
+ | Some d2 -> if d1 == d2 then d1 else f k d1 d2
+ in
+ let r = map2zo f1 f2 f r1 r2 in
+ join l k d r
+
+ let rec iter2zo f1 f2 f m1 m2 =
+ if m1 == m2 then () else
+ match m1 with
+ | Empty -> iter f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ iter2zo f1 f2 f l1 l2;
+ (match d2 with
+ | None -> f1 k d1
+ | Some d2 -> if d1 != d2 then f k d1 d2);
+ iter2zo f1 f2 f r1 r2
+
+ let rec fold2zo f1 f2 f m1 m2 acc =
+ if m1 == m2 then acc else
+ match m1 with
+ | Empty -> fold f2 m2 acc
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ let acc = fold2zo f1 f2 f l1 l2 acc in
+ let acc = match d2 with
+ | None -> f1 k d1 acc
+ | Some d2 -> if d1 == d2 then acc else f k d1 d2 acc
+ in
+ fold2zo f1 f2 f r1 r2 acc
+
+ let rec for_all2zo f1 f2 f m1 m2 =
+ (m1 == m2) ||
+ (match m1 with
+ | Empty -> for_all f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ (for_all2zo f1 f2 f l1 l2) &&
+ (match d2 with None -> f1 k d1 | Some d2 -> d1 == d2 || f k d1 d2) &&
+ (for_all2zo f1 f2 f r1 r2)
+ )
+
+ let rec exists2zo f1 f2 f m1 m2 =
+ (m1 != m2) &&
+ (match m1 with
+ | Empty -> exists f2 m2
+ | Node (l1,k,d1,r1,h1) ->
+ let l2, d2, r2 = cut k m2 in
+ (exists2zo f1 f2 f l1 l2) ||
+ (match d2 with None -> f1 k d1 | Some d2 -> d1 != d2 && f k d1 d2) ||
+ (exists2zo f1 f2 f r1 r2)
+ )
+
+
+ (* iterators limited to keys between two bounds *)
+
+ let rec map_slice f m lo hi =
+ match m with
+ | Empty -> Empty
+ | Node (l,k,d,r,h) ->
+ let c1, c2 = Ord.compare k lo, Ord.compare k hi in
+ let l = if c1 > 0 then map_slice f l lo k else l in
+ let d = if c1 >= 0 && c2 <= 0 then f k d else d in
+ let r = if c2 < 0 then map_slice f r k hi else r in
+ Node (l,k,d,r,h)
+
+ let rec iter_slice f m lo hi =
+ match m with
+ | Empty -> ()
+ | Node (l,k,d,r,_) ->
+ let c1, c2 = Ord.compare k lo, Ord.compare k hi in
+ if c1 > 0 then iter_slice f l lo k;
+ if c1 >= 0 && c2 <= 0 then f k d;
+ if c2 < 0 then iter_slice f r k hi
+
+ let rec fold_slice f m lo hi acc =
+ match m with
+ | Empty -> acc
+ | Node (l,k,d,r,_) ->
+ let c1, c2 = Ord.compare k lo, Ord.compare k hi in
+ let acc = if c1 > 0 then fold_slice f l lo k acc else acc in
+ let acc = if c1 >= 0 && c2 <= 0 then f k d acc else acc in
+ if c2 < 0 then fold_slice f r k hi acc else acc
+
+ let rec for_all_slice f m lo hi =
+ match m with
+ | Empty -> true
+ | Node (l,k,d,r,_) ->
+ let c1, c2 = Ord.compare k lo, Ord.compare k hi in
+ (c1 <= 0 || for_all_slice f l lo k) &&
+ (c1 < 0 || c2 > 0 || f k d) &&
+ (c2 >= 0 || for_all_slice f r k hi)
+
+ let rec exists_slice f m lo hi =
+ match m with
+ | Empty -> false
+ | Node (l,k,d,r,_) ->
+ let c1, c2 = Ord.compare k lo, Ord.compare k hi in
+ (c1 > 0 && exists_slice f l lo k) ||
+ (c1 >= 0 && c2 <= 0 && f k d) ||
+ (c2 < 0 && exists_slice f r k hi)
+
+
+ (* key set comparison *)
+
+ let rec key_equal m1 m2 =
+ (m1 == m2) ||
+ (match m1 with
+ | Empty -> m2 = Empty
+ | Node (l1, k, _, r1, _) ->
+ match cut k m2 with
+ | _, None, _ -> false
+ | l2, Some _, r2 -> key_equal l1 l2 && key_equal r1 r2
+ )
+
+ let rec key_subset m1 m2 =
+ (m1 == m2) ||
+ (match m1 with
+ | Empty -> true
+ | Node (l1, k, _, r1, _) ->
+ match cut k m2 with
+ | _, None, _ -> false
+ | l2, Some _, r2 -> key_subset l1 l2 && key_subset r1 r2
+ )
+
+
+ (* nagivation *)
+
+ let find_greater_equal k m =
+ let rec aux m found = match m with
+ | Empty -> (match found with None -> raise Not_found | Some x -> x)
+ | Node (l, kk, d, r, _) ->
+ let c = Ord.compare k kk in
+ if c = 0 then kk, d else
+ if c > 0 then aux r found else
+ aux l (Some (kk, d))
+ in
+ aux m None
+
+ let find_greater k m =
+ let rec aux m found = match m with
+ | Empty -> (match found with None -> raise Not_found | Some x -> x)
+ | Node (l, kk, d, r, _) ->
+ let c = Ord.compare k kk in
+ if c >= 0 then aux r found else
+ aux l (Some (kk, d))
+ in
+ aux m None
+
+ let find_less_equal k m =
+ let rec aux m found = match m with
+ | Empty -> (match found with None -> raise Not_found | Some x -> x)
+ | Node (l, kk, d, r, _) ->
+ let c = Ord.compare k kk in
+ if c = 0 then kk, d else
+ if c < 0 then aux l found else
+ aux r (Some (kk, d))
+ in
+ aux m None
+
+ let find_less k m =
+ let rec aux m found = match m with
+ | Empty -> (match found with None -> raise Not_found | Some x -> x)
+ | Node (l, kk, d, r, _) ->
+ let c = Ord.compare k kk in
+ if c <= 0 then aux l found else
+ aux r (Some (kk, d))
+ in
+ aux m None
+
+
+end: S with type key = Ord.t)