added PHashtbl.get_eq/get_hash, to access the functions;

added a function to create a PHashtbl from a module;
added PHashtbl.map

pHashtbl.ml

@@ -51,6 +51,17 @@ let create ?(max_load=0.8) ?(eq=fun x y -> x = y)
     eq;
     hash; }
 
+module type Hashable = sig
+  type t
+  val equal : t -> t -> bool
+  val hash : t -> int
+end
+
+(** Create a hashtable from the given 'typeclass' *)
+let create_tc (type key) (h : (module Hashable with type t = key)) size =
+  let module H = (val h) in
+  create ~eq:H.equal ~hash:H.hash size
+
 (** Copy of the hashtable *)
 let copy t = {
   eq = t.eq;
@@ -179,6 +190,17 @@ let fold f acc t =
   done;
   !acc
 
+(** Map, replaces values by other values *)
+let map f t =
+  let t' = create ~eq:t.eq ~hash:t.hash (Array.length t.buckets) in
+  for i = 0 to Array.length t.buckets - 1 do
+    match t.buckets.(i) with
+    | (_, _, Empty) -> ()
+    | (k, _, Deleted) -> t'.buckets.(i) <- my_deleted k
+    | (k, v, Used) -> t'.buckets.(i) <- (k, f k v, Used)
+  done;
+  t'
+
 (** Destructive filter (remove bindings that do not satisfiy predicate) *)
 let filter pred t =
   for i = 0 to Array.length t.buckets - 1 do
@@ -201,3 +223,7 @@ let to_seq t =
 
 (** Statistics on the table *)
 let stats t = (Array.length t.buckets, t.size, t.size, 0, 0, 1)
+
+let get_eq t = t.eq
+
+let get_hash t = t.hash

pHashtbl.mli

@@ -25,8 +25,16 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Open addressing hashtable, with linear probing} *)
 
-type ('a, 'b) t
-  (** Polymorphic hashtable *)
+type ('a, 'b) t = private {
+  mutable buckets : ('a * 'b * state) array;
+  mutable size : int;
+  eq : 'a -> 'a -> bool;
+  hash : 'a -> int;
+  max_load : float;
+} (** A hashtable is an array of (key, value) buckets that have a state,
+      plus the size of the table and equality/hash functions *)
+and state = Used | Empty | Deleted
+  (** state of a bucket *)
 
 val create : ?max_load:float -> ?eq:('a -> 'a -> bool) ->
               ?hash:('a -> int) -> int -> ('a, 'b) t
@@ -34,6 +42,15 @@ val create : ?max_load:float -> ?eq:('a -> 'a -> bool) ->
       and must be in ]0, 1[. Functions for equality check and hashing
       can also be provided. *)
 
+module type Hashable = sig
+  type t
+  val equal : t -> t -> bool
+  val hash : t -> int
+end
+
+val create_tc : (module Hashable with type t = 'a) -> int -> ('a, 'b) t
+  (** Create a hashtable from the given 'typeclass' *)
+
 val copy : ('a, 'b) t -> ('a, 'b) t
   (** Copy of the hashtable *)
 
@@ -61,6 +78,9 @@ val mem : ('a,_) t -> 'a -> bool
 val iter : ('a -> 'b -> unit) -> ('a, 'b) t -> unit
   (** Iterate on bindings *)
 
+val map : ('a -> 'b -> 'c) -> ('a, 'b) t -> ('a, 'c) t
+  (** Map, replaces values by other values *)
+
 val filter : ('a -> 'b -> bool) -> ('a, 'b) t -> unit
   (** Destructive filter (remove bindings that do not satisfiy predicate) *)
 
@@ -75,3 +95,7 @@ val to_seq : ('a, 'b) t -> ('a * 'b) Sequence.t
 
 val stats : (_, _) t -> int * int * int * int * int * int
   (** Cf Weak.S *)
+
+val get_eq : ('v, _) t -> ('v -> 'v -> bool)
+
+val get_hash : ('v, _) t -> ('v -> int)

tests/test_pHashtbl.ml

@@ -83,6 +83,16 @@ let test_filter () =
   OUnit.assert_bool "mem" (PHashtbl.mem h 4);
   OUnit.assert_bool "mem" (PHashtbl.mem h 2)
 
+let test_map () =
+  let h = PHashtbl.create 5 in
+  PHashtbl.of_seq h my_seq;
+  let h' = PHashtbl.map (fun k v -> String.uppercase v) h in
+  OUnit.assert_equal (PHashtbl.length h') 4;
+  OUnit.assert_equal (PHashtbl.find h' 1) "A";
+  OUnit.assert_equal (PHashtbl.find h' 2) "B";
+  OUnit.assert_equal (PHashtbl.find h' 3) "C";
+  OUnit.assert_equal (PHashtbl.find h' 4) "D"
+
 let suite =
   "test_pHashtbl" >:::
     [ "test_add" >:: test_add;