ocaml-containers/src/core/CCHashtbl.ml
Simon Cruanes 960e704bb1 test: disable labels for tests
necessary for the consistency checks of Label modules
2018-04-08 18:48:54 -05:00

361 lines
9.8 KiB
OCaml

(* This file is free software, part of containers. See file "license" for more details. *)
(** {1 Extension to the standard Hashtbl} *)
type 'a sequence = ('a -> unit) -> unit
type 'a eq = 'a -> 'a -> bool
type 'a hash = 'a -> int
type 'a printer = Format.formatter -> 'a -> unit
(** {2 Polymorphic tables} *)
module Poly = struct
let get tbl x =
try Some (Hashtbl.find tbl x)
with Not_found -> None
let get_or tbl x ~default =
try Hashtbl.find tbl x
with Not_found -> default
(*$=
"c" (let tbl = of_list [1,"a"; 2,"b"] in get_or tbl 3 ~default:"c")
"b" (let tbl = of_list [1,"a"; 2,"b"] in get_or tbl 2 ~default:"c")
*)
let keys tbl k = Hashtbl.iter (fun key _ -> k key) tbl
let values tbl k = Hashtbl.iter (fun _ v -> k v) tbl
let keys_list tbl = Hashtbl.fold (fun k _ a -> k::a) tbl []
let values_list tbl = Hashtbl.fold (fun _ v a -> v::a) tbl []
let add_list tbl k v =
let l = try Hashtbl.find tbl k with Not_found -> [] in
Hashtbl.replace tbl k (v::l)
let incr ?(by=1) tbl x =
let n = get_or tbl x ~default:0 in
if n+by <= 0
then Hashtbl.remove tbl x
else Hashtbl.replace tbl x (n+by)
let decr ?(by=1) tbl x =
try
let n = Hashtbl.find tbl x in
if n-by <= 0
then Hashtbl.remove tbl x
else Hashtbl.replace tbl x (n-by)
with Not_found -> ()
let map_list f h =
Hashtbl.fold
(fun x y acc -> f x y :: acc)
h []
(*$T
of_list [1,"a"; 2,"b"] |> map_list (fun x y -> string_of_int x ^ y) \
|> List.sort Pervasives.compare = ["1a"; "2b"]
*)
let to_seq tbl k = Hashtbl.iter (fun key v -> k (key,v)) tbl
let add_seq tbl seq = seq (fun (k,v) -> Hashtbl.add tbl k v)
let of_seq seq =
let tbl = Hashtbl.create 32 in
add_seq tbl seq;
tbl
let add_seq_count tbl seq = seq (fun k -> incr tbl k)
let of_seq_count seq =
let tbl = Hashtbl.create 32 in
add_seq_count tbl seq;
tbl
let to_list tbl =
Hashtbl.fold
(fun k v l -> (k,v) :: l)
tbl []
let of_list l =
let tbl = Hashtbl.create 32 in
List.iter (fun (k,v) -> Hashtbl.add tbl k v) l;
tbl
let update tbl ~f ~k =
let v = get tbl k in
match v, f k v with
| None, None -> ()
| None, Some v' -> Hashtbl.add tbl k v'
| Some _, Some v' -> Hashtbl.replace tbl k v'
| Some _, None -> Hashtbl.remove tbl k
(*$R
let tbl = Hashtbl.create 32 in
update tbl ~f:(fun _ _ -> Some "1") ~k:1;
assert_equal (Some "1") (get tbl 1);
update tbl ~f:(fun _ v->match v with Some _ -> assert false | None -> Some "2") ~k:2;
assert_equal (Some "2") (get tbl 2);
assert_equal 2 (Hashtbl.length tbl);
update tbl ~f:(fun _ _ -> None) ~k:1;
assert_equal None (get tbl 1);
*)
let get_or_add tbl ~f ~k =
try Hashtbl.find tbl k
with Not_found ->
let v = f k in
Hashtbl.add tbl k v;
v
(*$R
let tbl = Hashtbl.create 32 in
let v1 = get_or_add tbl ~f:(fun _ -> "1") ~k:1 in
assert_equal "1" v1;
assert_equal (Some "1") (get tbl 1);
let v2 = get_or_add tbl ~f:(fun _ ->"2") ~k:2 in
assert_equal "2" v2;
assert_equal (Some "2") (get tbl 2);
assert_equal "2" (get_or_add tbl ~f:(fun _ -> assert false) ~k:2);
assert_equal 2 (Hashtbl.length tbl);
()
*)
let pp pp_k pp_v fmt m =
Format.fprintf fmt "@[<hov2>tbl {@,";
let first = ref true in
Hashtbl.iter
(fun k v ->
if !first then first := false else Format.pp_print_string fmt ", ";
pp_k fmt k;
Format.pp_print_string fmt " -> ";
pp_v fmt v;
Format.pp_print_cut fmt ()
) m;
Format.fprintf fmt "}@]"
end
include Poly
(** {2 Functor} *)
module type S = sig
include Hashtbl.S
val get : 'a t -> key -> 'a option
(** Safe version of {!Hashtbl.find} *)
val get_or : 'a t -> key -> default:'a -> 'a
(** [get_or tbl k ~default] returns the value associated to [k] if present,
and returns [default] otherwise (if [k] doesn't belong in [tbl])
@since 0.16 *)
val add_list : 'a list t -> key -> 'a -> unit
(** [add_list tbl x y] adds [y] to the list [x] is bound to. If [x] is
not bound, it becomes bound to [[y]].
@since 0.16 *)
val incr : ?by:int -> int t -> key -> unit
(** [incr ?by tbl x] increments or initializes the counter associated with [x].
If [get tbl x = None], then after update, [get tbl x = Some 1];
otherwise, if [get tbl x = Some n], now [get tbl x = Some (n+1)].
@param by if specified, the int value is incremented by [by] rather than 1
@since 0.16 *)
val decr : ?by:int -> int t -> key -> unit
(** Like {!incr} but substract 1 (or the value of [by]).
If the value reaches 0, the key is removed from the table.
This does nothing if the key is not already present in the table.
@since 0.16 *)
val keys : 'a t -> key sequence
(** Iterate on keys (similar order as {!Hashtbl.iter}) *)
val values : 'a t -> 'a sequence
(** Iterate on values in the table *)
val keys_list : _ t -> key list
(** [keys t] is the list of keys in [t].
@since 0.8 *)
val values_list : 'a t -> 'a list
(** [values t] is the list of values in [t].
@since 0.8 *)
val map_list : (key -> 'a -> 'b) -> 'a t -> 'b list
(** Map on a hashtable's items, collect into a list *)
val to_seq : 'a t -> (key * 'a) sequence
(** Iterate on values in the table *)
val of_seq : (key * 'a) sequence -> 'a t
(** From the given bindings, added in order *)
val add_seq : 'a t -> (key * 'a) sequence -> unit
(** Add the corresponding pairs to the table, using {!Hashtbl.add}.
@since 0.16 *)
val add_seq_count : int t -> key sequence -> unit
(** [add_seq_count tbl seq] increments the count of each element of [seq]
by calling {!incr}. This is useful for counting how many times each
element of [seq] occurs.
@since 0.16 *)
val of_seq_count : key sequence -> int t
(** Like {!add_seq_count}, but allocates a new table and returns it
@since 0.16 *)
val to_list : 'a t -> (key * 'a) list
(** List of bindings (order unspecified) *)
val of_list : (key * 'a) list -> 'a t
(** Build a table from the given list of bindings [k_i -> v_i],
added in order using {!add}. If a key occurs several times,
it will be added several times, and the visible binding
will be the last one. *)
val update : 'a t -> f:(key -> 'a option -> 'a option) -> k:key -> unit
(** [update tbl ~f ~k] updates key [k] by calling [f k (Some v)] if
[k] was mapped to [v], or [f k None] otherwise; if the call
returns [None] then [k] is removed/stays removed, if the call
returns [Some v'] then the binding [k -> v'] is inserted
using {!Hashtbl.replace}
@since 0.14 *)
val get_or_add : 'a t -> f:(key -> 'a) -> k:key -> 'a
(** [get_or_add tbl ~k ~f] finds and returns the binding of [k]
in [tbl], if it exists. If it does not exist, then [f k]
is called to obtain a new binding [v]; [k -> v] is added
to [tbl] and [v] is returned.
@since 1.0 *)
val pp : key printer -> 'a printer -> 'a t printer
(** Printer for table
@since 0.13
Renamed from [print] @since 2.0 *)
end
(*$inject
module T = Make(CCInt)
*)
module Make(X : Hashtbl.HashedType)
: S with type key = X.t and type 'a t = 'a Hashtbl.Make(X).t
= struct
include Hashtbl.Make(X)
let get tbl x =
try Some (find tbl x)
with Not_found -> None
let get_or tbl x ~default =
try find tbl x
with Not_found -> default
(*$=
"c" (let tbl = T.of_list [1,"a"; 2,"b"] in T.get_or tbl 3 ~default:"c")
"b" (let tbl = T.of_list [1,"a"; 2,"b"] in T.get_or tbl 2 ~default:"c")
*)
let incr ?(by=1) tbl x =
let n = get_or tbl x ~default:0 in
if n+by <= 0
then remove tbl x
else replace tbl x (n+by)
(*$R
let tbl = T.create 32 in
T.incr tbl 1 ;
T.incr tbl 2;
T.incr tbl 1;
assert_equal 2 (T.find tbl 1);
assert_equal 1 (T.find tbl 2);
assert_equal 2 (T.length tbl);
T.decr tbl 2;
assert_equal 0 (T.get_or tbl 2 ~default:0);
assert_equal 1 (T.length tbl);
assert_bool "2 removed" (not (T.mem tbl 2));
*)
let add_list tbl k v =
let l = try find tbl k with Not_found -> [] in
replace tbl k (v::l)
let decr ?(by=1) tbl x =
try
let n = find tbl x in
if n-by <= 0
then remove tbl x
else replace tbl x (n-by)
with Not_found -> ()
let keys tbl k = iter (fun key _ -> k key) tbl
let values tbl k = iter (fun _ v -> k v) tbl
let keys_list tbl = fold (fun k _ a -> k::a) tbl []
let values_list tbl = fold (fun _ v a -> v::a) tbl []
let map_list f h =
fold
(fun x y acc -> f x y :: acc)
h []
let update tbl ~f ~k =
let v = get tbl k in
match v, f k v with
| None, None -> ()
| None, Some v' -> add tbl k v'
| Some _, Some v' -> replace tbl k v'
| Some _, None -> remove tbl k
let get_or_add tbl ~f ~k =
try find tbl k
with Not_found ->
let v = f k in
add tbl k v;
v
let to_seq tbl k = iter (fun key v -> k (key,v)) tbl
let add_seq tbl seq = seq (fun (k,v) -> add tbl k v)
let of_seq seq =
let tbl = create 32 in
add_seq tbl seq;
tbl
let add_seq_count tbl seq = seq (fun k -> incr tbl k)
let of_seq_count seq =
let tbl = create 32 in
add_seq_count tbl seq;
tbl
let to_list tbl =
fold
(fun k v l -> (k,v) :: l)
tbl []
let of_list l =
let tbl = create 32 in
List.iter (fun (k,v) -> add tbl k v) l;
tbl
let pp pp_k pp_v fmt m =
Format.fprintf fmt "@[<hov2>tbl {@,";
let first = ref true in
iter
(fun k v ->
if !first then first := false else Format.pp_print_string fmt ", ";
pp_k fmt k;
Format.pp_print_string fmt " -> ";
pp_v fmt v;
Format.pp_print_cut fmt ()
) m;
Format.fprintf fmt "}@]"
end