X-Git-Url: http://git.nguyen.vg/gitweb/?a=blobdiff_plain;f=hcons.ml;fp=hcons.ml;h=293b90f2e032dc02ae128f6ff383d0f6f40fd00f;hb=f1da22caf34bc3367984228ace9e7e7aa0760f0a;hp=0000000000000000000000000000000000000000;hpb=b1e6806834df253d5454fffad7f14fb24c74af70;p=SXSI%2Fxpathcomp.git

diff --git a/hcons.ml b/hcons.ml
new file mode 100644
index 0000000..293b90f
--- /dev/null
+++ b/hcons.ml
@@ -0,0 +1,37 @@
+INCLUDE "utils.ml"
+module type S = 
+sig
+  type data
+  type t
+  val make : data -> t
+  val node : t -> data
+  val hash : t -> int
+  val uid : t -> int
+  val equal : t -> t -> bool
+end
+module Make (H : Hashtbl.HashedType) : S with type data = H.t =
+struct
+  type data = H.t
+  type t =  { id : int;
+	      key : int; (* hash *)
+	      node : data;
+	    }
+  
+  let node t = t.node
+  let hash t = t.key
+  let uid t = t.id
+  let gen_uid  =
+    let id = ref ~-1 in 
+      fun () -> incr id;!id
+  let equal t1 t2 = t1 == t2 || t1.id == t2.id
+  module WH = Weak.Make( struct 
+			   type _t = t 
+			   type t = _t 
+			   let hash = hash
+			   let equal a b = H.equal a.node b.node 
+			 end)
+  let pool = WH.create MED_H_SIZE
+  let make x = 
+    let cell = { id = gen_uid(); key = H.hash x; node = x } in
+      WH.merge pool cell
+end