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(**************************************************************************)
(* *)
(* SMTCoq *)
(* Copyright (C) 2011 - 2019 *)
(* *)
(* See file "AUTHORS" for the list of authors *)
(* *)
(* This file is distributed under the terms of the CeCILL-C licence *)
(* *)
(**************************************************************************)
(*s Hash tables for hash-consing. (Some code is borrowed from the ocaml
standard library, which is copyright 1996 INRIA.) *)
module type HashedType =
sig
type t
val equal : t -> t -> bool
val hash : t -> int
val tag : int -> t -> t
end
module type S =
sig
type t
val hashcons : t -> t
val iter : (t -> unit) -> unit
val stats : unit -> int * int * int * int * int * int
end
module Make(H : HashedType) : (S with type t = H.t) =
struct
type t = H.t
module WH = Weak.Make (H)
let next_tag = ref 0
let htable = WH.create 5003
let hashcons d =
let d = H.tag !next_tag d in
let o = WH.merge htable d in
if o == d then incr next_tag;
o
let iter f = WH.iter f htable
let stats () = WH.stats htable
end
type 'a hash_consed = {
tag : int;
node : 'a }
module type HashedType_consed =
sig
type t
val equal : t -> t -> bool
val hash : t -> int
end
module type S_consed =
sig
type key
val hashcons : key -> key hash_consed
val iter : (key hash_consed -> unit) -> unit
val stats : unit -> int * int * int * int * int * int
end
module Make_consed(H : HashedType_consed) : (S_consed with type key = H.t) =
struct
module M = Make(struct
type t = H.t hash_consed
let hash x = H.hash x.node
let equal x y = H.equal x.node y.node
let tag i x = {x with tag = i}
end)
include M
type key = H.t
let hashcons x = M.hashcons {tag = -1; node = x}
end
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