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updated CCPersistentHashtbl with new functions;

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updated doc, simplified code
This commit is contained in:
Simon Cruanes 2014-06-28 03:53:21 +02:00
parent a356d811a7
commit 735a11e5ec
2 changed files with 265 additions and 117 deletions
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290
core/CCPersistentHashtbl.ml
View file

@ -26,6 +26,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
(** {1 Persistent hash-table on top of OCaml's hashtables} *)
type 'a sequence = ('a -> unit) -> unit
type 'a printer = Buffer.t -> 'a -> unit
type 'a formatter = Format.formatter -> 'a -> unit
type 'a equal = 'a -> 'a -> bool
module type HashedType = sig
type t
@ -40,52 +43,92 @@ module type S = sig
type 'a t
val empty : unit -> 'a t
(** Empty table. The table will be allocated at the first binding *)
(** Empty table. The table will be allocated at the first binding *)
val create : int -> 'a t
(** Create a new hashtable *)
(** Create a new hashtable, with the given initial capacity *)
val is_empty : 'a t -> bool
(** Is the table empty? *)
(** Is the table empty? *)
val find : 'a t -> key -> 'a
(** Find the value for this key, or raise Not_found *)
(** Find the value for this key, or fails
@raise Not_found if the key is not present in the table *)
val get_exn : key -> 'a t -> 'a
(** Synonym to {!find} with flipped arguments *)
val get : key -> 'a t -> 'a option
(** Safe version of !{get_exn} *)
val mem : 'a t -> key -> bool
(** Is the key bound? *)
(** Is the key bound? *)
val length : 'a t -> int
(** Number of bindings *)
val length : _ t -> int
(** Number of bindings *)
val replace : 'a t -> key -> 'a -> 'a t
(** Add the binding to the table, returning a new table. This erases
the current binding for [key], if any. *)
(** Add the binding to the table, returning a new table. This erases
the current binding for [key], if any. *)
val update : 'a t -> key -> ('a option -> 'a option) -> 'a t
(** [update tbl key f] calls [f None] if [key] doesn't belong in [tbl],
[f (Some v)] if [key -> v] otherwise; If [f] returns [None] then
[key] is removed, else it returns [Some v'] and [key -> v'] is added. *)
val remove : 'a t -> key -> 'a t
(** Remove the key *)
(** Remove the key *)
val copy : 'a t -> 'a t
(** Fresh copy of the table; the underlying structure is not shared
anymore, so using both tables alternatively will be efficient *)
(** Fresh copy of the table; the underlying structure is not shared
anymore, so using both tables alternatively will be efficient *)
val merge : (key -> 'a option -> 'a option -> 'a option) -> 'a t -> 'a t -> 'a t
(** Merge two tables together into a new table *)
val merge : (key -> 'a option -> 'a option -> 'a option) ->
'a t -> 'a t -> 'a t
(** Merge two tables together into a new table. The function's argument
correspond to values associated with the key (if present); if the
function returns [None] the key will not appear in the result. *)
val iter : 'a t -> (key -> 'a -> unit) -> unit
(** Iterate over bindings *)
(** Iterate over bindings *)
val fold : ('b -> key -> 'a -> 'b) -> 'b -> 'a t -> 'b
(** Fold over bindings *)
(** Fold over bindings *)
val of_seq : ?init:'a t -> (key * 'a) sequence -> 'a t
(** Add (replace) bindings from the sequence to the table *)
val map : (key -> 'a -> 'b) -> 'a t -> 'b t
(** Map all values *)
val of_list : ?init:'a t -> (key * 'a) list -> 'a t
val filter : (key -> 'a -> bool) -> 'a t -> 'a t
val filter_map : (key -> 'a -> 'b option) -> 'a t -> 'b t
val for_all : (key -> 'a -> bool) -> 'a t -> bool
val exists : (key -> 'a -> bool) -> 'a t -> bool
(** {3 Conversions} *)
val of_seq : (key * 'a) sequence -> 'a t
(** Add (replace) bindings from the sequence to the table *)
val of_list : (key * 'a) list -> 'a t
val add_seq : 'a t -> (key * 'a) sequence -> 'a t
val add_list : 'a t -> (key * 'a) list -> 'a t
val to_seq : 'a t -> (key * 'a) sequence
(** Sequence of the bindings of the table *)
(** Sequence of the bindings of the table *)
val to_list : 'a t -> (key * 'a) list
(** {3 Misc} *)
val equal : 'a equal -> 'a t equal
val pp : key printer -> 'a printer -> 'a t printer
val print : key formatter -> 'a formatter -> 'a t formatter
end
(** {2 Implementation} *)
@ -107,64 +150,55 @@ module Make(H : HashedType) : S with type key = H.t = struct
let empty () = create 11
(** Reroot: modify the zipper so that the current node is a proper
hashtable, and return the hashtable *)
let reroot t =
(* pass continuation to get a tailrec rerooting *)
let rec reroot t k = match !t with
| Table tbl -> k tbl (* done *)
| Add (key, v, t') ->
reroot t'
(fun tbl ->
t' := Remove (key, t);
Table.add tbl key v;
t := Table tbl;
k tbl)
| Replace (key, v, t') ->
reroot t'
(fun tbl ->
let v' = Table.find tbl key in
t' := Replace (key, v', t);
t := Table tbl;
Table.replace tbl key v;
k tbl)
| Remove (key, t') ->
reroot t'
(fun tbl ->
let v = Table.find tbl key in
t' := Add (key, v, t);
t := Table tbl;
Table.remove tbl key;
k tbl)
in
match !t with
(* pass continuation to get a tailrec rerooting *)
let rec _reroot t k = match !t with
| Table tbl -> k tbl (* done *)
| Add (key, v, t') ->
_reroot t'
(fun tbl ->
t' := Remove (key, t);
Table.add tbl key v;
t := Table tbl;
k tbl)
| Replace (key, v, t') ->
_reroot t'
(fun tbl ->
let v' = Table.find tbl key in
t' := Replace (key, v', t);
t := Table tbl;
Table.replace tbl key v;
k tbl)
| Remove (key, t') ->
_reroot t'
(fun tbl ->
let v = Table.find tbl key in
t' := Add (key, v, t);
t := Table tbl;
Table.remove tbl key;
k tbl)
(* Reroot: modify the zipper so that the current node is a proper
hashtable, and return the hashtable *)
let reroot t = match !t with
| Table tbl -> tbl
| _ -> reroot t (fun x -> x)
| _ -> _reroot t (fun x -> x)
let is_empty t =
match !t with
| Table tbl -> Table.length tbl = 0
| _ -> Table.length (reroot t) = 0
let is_empty t = Table.length (reroot t) = 0
let find t k =
match !t with
| Table tbl -> Table.find tbl k
| _ -> Table.find (reroot t) k
let find t k = Table.find (reroot t) k
let mem t k =
match !t with
| Table tbl -> Table.mem tbl k
| _ -> Table.mem (reroot t) k
let get_exn k t = find t k
let length t =
match !t with
| Table tbl -> Table.length tbl
| _ -> Table.length (reroot t)
let get k t =
try Some (find t k)
with Not_found -> None
let mem t k = Table.mem (reroot t) k
let length t = Table.length (reroot t)
let replace t k v =
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t in
let tbl = reroot t in
(* create the new hashtable *)
let t' = ref (Table tbl) in
(* update [t] to point to the new hashtable *)
@ -172,15 +206,14 @@ module Make(H : HashedType) : S with type key = H.t = struct
let v' = Table.find tbl k in
t := Replace (k, v', t')
with Not_found ->
t := Remove (k, t'));
t := Remove (k, t')
);
(* modify the underlying hashtable *)
Table.replace tbl k v;
t'
let remove t k =
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t in
let tbl = reroot t in
try
let v' = Table.find tbl k in
(* value present, make a new hashtable without this value *)
@ -192,26 +225,63 @@ module Make(H : HashedType) : S with type key = H.t = struct
(* not member, nothing to do *)
t
let update t k f =
let v = get k t in
match v, f v with
| None, None -> t (* no change *)
| Some _, None -> remove t k
| _, Some v' -> replace t k v'
let copy t =
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t in
let tbl = reroot t in
(* no one will point to the new [t] *)
let t = ref (Table (Table.copy tbl)) in
t
let iter t f =
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t in
let tbl = reroot t in
Table.iter f tbl
let fold f acc t =
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t in
let tbl = reroot t in
Table.fold (fun k v acc -> f acc k v) tbl acc
let map f t =
let tbl = reroot t in
let res = Table.create (Table.length tbl) in
Table.iter (fun k v -> Table.replace res k (f k v)) tbl;
ref (Table res)
let filter p t =
let tbl = reroot t in
let res = Table.create (Table.length tbl) in
Table.iter (fun k v -> if p k v then Table.replace res k v) tbl;
ref (Table res)
let filter_map f t =
let tbl = reroot t in
let res = Table.create (Table.length tbl) in
Table.iter
(fun k v -> match f k v with
| None -> ()
| Some v' -> Table.replace res k v'
) tbl;
ref (Table res)
exception ExitPTbl
let for_all p t =
try
iter t (fun k v -> if not (p k v) then raise ExitPTbl);
true
with ExitPTbl -> false
let exists p t =
try
iter t (fun k v -> if p k v then raise ExitPTbl);
false
with ExitPTbl -> true
let merge f t1 t2 =
let tbl = Table.create (max (length t1) (length t2)) in
iter t1
@ -227,15 +297,17 @@ module Make(H : HashedType) : S with type key = H.t = struct
| Some v' -> Table.replace tbl k v2);
ref (Table tbl)
let of_seq ?init seq =
let tbl = match init with
| None -> Table.create 5
| Some t -> Table.copy (reroot t) in
seq (fun (k,v) -> Table.replace tbl k v);
ref (Table tbl)
let add_seq init seq =
let tbl = ref init in
seq (fun (k,v) -> tbl := replace !tbl k v);
!tbl
let of_list ?init l =
of_seq ?init (fun k -> List.iter k l)
let of_seq seq = add_seq (empty ()) seq
let add_list init l =
add_seq init (fun k -> List.iter k l)
let of_list l = add_list (empty ()) l
let to_list t =
let tbl = reroot t in
@ -244,10 +316,36 @@ module Make(H : HashedType) : S with type key = H.t = struct
let to_seq t =
fun k ->
let tbl = match !t with
| Table tbl -> tbl
| _ -> reroot t
in
let tbl = reroot t in
Table.iter (fun x y -> k (x,y)) tbl
let equal eq t1 t2 =
length t1 = length t2
&&
for_all
(fun k v -> match get k t2 with
| None -> false
| Some v' -> eq v v'
) t1
let pp pp_k pp_v buf t =
Buffer.add_string buf "{";
let first = ref true in
iter t
(fun k v ->
if !first then first:=false else Buffer.add_string buf ", ";
Printf.bprintf buf "%a -> %a" pp_k k pp_v v
);
Buffer.add_string buf "}"
let print pp_k pp_v fmt t =
Format.pp_print_string fmt "{";
let first = ref true in
iter t
(fun k v ->
if !first then first:=false else Format.pp_print_string fmt ", ";
Format.fprintf fmt "%a -> %a" pp_k k pp_v v
);
Format.pp_print_string fmt "}"
end

92
core/CCPersistentHashtbl.mli
View file

@ -23,9 +23,19 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*)
(** {1 Persistent hash-table on top of OCaml's hashtables} *)
(** {1 Persistent hash-table on top of OCaml's hashtables}
Almost as efficient as the regular Hashtbl type, but with a persistent
interface (rewinding changes to get back in the past history). This is
mostly useful for backtracking-like uses, or forward uses (never using
old values).
This module is not thread-safe. *)
type 'a sequence = ('a -> unit) -> unit
type 'a printer = Buffer.t -> 'a -> unit
type 'a formatter = Format.formatter -> 'a -> unit
type 'a equal = 'a -> 'a -> bool
module type HashedType = sig
type t
@ -40,52 +50,92 @@ module type S = sig
type 'a t
val empty : unit -> 'a t
(** Empty table. The table will be allocated at the first binding *)
(** Empty table. The table will be allocated at the first binding *)
val create : int -> 'a t
(** Create a new hashtable *)
(** Create a new hashtable, with the given initial capacity *)
val is_empty : 'a t -> bool
(** Is the table empty? *)
(** Is the table empty? *)
val find : 'a t -> key -> 'a
(** Find the value for this key, or raise Not_found *)
(** Find the value for this key, or fails
@raise Not_found if the key is not present in the table *)
val get_exn : key -> 'a t -> 'a
(** Synonym to {!find} with flipped arguments *)
val get : key -> 'a t -> 'a option
(** Safe version of !{get_exn} *)
val mem : 'a t -> key -> bool
(** Is the key bound? *)
(** Is the key bound? *)
val length : 'a t -> int
(** Number of bindings *)
val length : _ t -> int
(** Number of bindings *)
val replace : 'a t -> key -> 'a -> 'a t
(** Add the binding to the table, returning a new table. This erases
the current binding for [key], if any. *)
(** Add the binding to the table, returning a new table. This erases
the current binding for [key], if any. *)
val update : 'a t -> key -> ('a option -> 'a option) -> 'a t
(** [update tbl key f] calls [f None] if [key] doesn't belong in [tbl],
[f (Some v)] if [key -> v] otherwise; If [f] returns [None] then
[key] is removed, else it returns [Some v'] and [key -> v'] is added. *)
val remove : 'a t -> key -> 'a t
(** Remove the key *)
(** Remove the key *)
val copy : 'a t -> 'a t
(** Fresh copy of the table; the underlying structure is not shared
anymore, so using both tables alternatively will be efficient *)
(** Fresh copy of the table; the underlying structure is not shared
anymore, so using both tables alternatively will be efficient *)
val merge : (key -> 'a option -> 'a option -> 'a option) -> 'a t -> 'a t -> 'a t
(** Merge two tables together into a new table *)
val merge : (key -> 'a option -> 'a option -> 'a option) ->
'a t -> 'a t -> 'a t
(** Merge two tables together into a new table. The function's argument
correspond to values associated with the key (if present); if the
function returns [None] the key will not appear in the result. *)
val iter : 'a t -> (key -> 'a -> unit) -> unit
(** Iterate over bindings *)
(** Iterate over bindings *)
val fold : ('b -> key -> 'a -> 'b) -> 'b -> 'a t -> 'b
(** Fold over bindings *)
(** Fold over bindings *)
val of_seq : ?init:'a t -> (key * 'a) sequence -> 'a t
(** Add (replace) bindings from the sequence to the table *)
val map : (key -> 'a -> 'b) -> 'a t -> 'b t
(** Map all values *)
val of_list : ?init:'a t -> (key * 'a) list -> 'a t
val filter : (key -> 'a -> bool) -> 'a t -> 'a t
val filter_map : (key -> 'a -> 'b option) -> 'a t -> 'b t
val for_all : (key -> 'a -> bool) -> 'a t -> bool
val exists : (key -> 'a -> bool) -> 'a t -> bool
(** {3 Conversions} *)
val of_seq : (key * 'a) sequence -> 'a t
(** Add (replace) bindings from the sequence to the table *)
val of_list : (key * 'a) list -> 'a t
val add_seq : 'a t -> (key * 'a) sequence -> 'a t
val add_list : 'a t -> (key * 'a) list -> 'a t
val to_seq : 'a t -> (key * 'a) sequence
(** Sequence of the bindings of the table *)
(** Sequence of the bindings of the table *)
val to_list : 'a t -> (key * 'a) list
(** {3 Misc} *)
val equal : 'a equal -> 'a t equal
val pp : key printer -> 'a printer -> 'a t printer
val print : key formatter -> 'a formatter -> 'a t formatter
end
(** {2 Implementation} *)