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https://github.com/c-cube/sidekick.git
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76 lines
2 KiB
OCaml
76 lines
2 KiB
OCaml
module type S = sig
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type key
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type 'a t
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val create : ?size:int -> unit -> 'a t
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val find : 'a t -> key -> 'a
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(** @raise Not_found if the key is not present *)
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val get : 'a t -> key -> 'a option
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val mem : _ t -> key -> bool
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val length : _ t -> int
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val iter : (key -> 'a -> unit) -> 'a t -> unit
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val to_iter : 'a t -> (key * 'a) Iter.t
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val add : 'a t -> key -> 'a -> unit
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val remove : _ t -> key -> unit
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val push_level : _ t -> unit
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val pop_levels : _ t -> int -> unit
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end
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module type ARG = sig
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type t
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val equal : t -> t -> bool
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val hash : t -> int
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end
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module Make(A : ARG) = struct
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type key = A.t
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module M = CCHashtbl.Make(A)
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module BS = Backtrack_stack
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type 'a undo_op = Add of key * 'a | Remove of key
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type 'a t = {
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tbl: 'a M.t;
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undo: 'a undo_op BS.t;
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}
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let create ?(size=32) () : _ t = { tbl=M.create size; undo=BS.create() }
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let apply_undo self u =
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match u with
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| Add (k,v) -> M.replace self.tbl k v
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| Remove k -> M.remove self.tbl k
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let[@inline] find (self:_ t) k = M.find self.tbl k
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let[@inline] get (self:_ t) k : _ option = M.get self.tbl k
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let[@inline] mem self k = M.mem self.tbl k
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let[@inline] length self = M.length self.tbl
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let[@inline] iter f self = M.iter f self.tbl
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let[@inline] push_level self = BS.push_level self.undo
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let[@inline] pop_levels self n = BS.pop_levels self.undo n ~f:(apply_undo self)
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let add self k v : unit =
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if BS.n_levels self.undo > 0 then (
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try
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let old_v = M.find self.tbl k in
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BS.push self.undo (Add (k,old_v))
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with Not_found ->
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BS.push self.undo (Remove k)
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);
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M.replace self.tbl k v
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let remove self k : unit =
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if BS.n_levels self.undo > 0 then (
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try
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(* get value to restore it *)
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let v = M.find self.tbl k in
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M.remove self.tbl k;
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BS.push self.undo (Add (k,v));
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with Not_found -> ()
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) else (
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M.remove self.tbl k
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)
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let[@inline] to_iter self yield = M.iter (fun k v -> yield (k,v)) self.tbl
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end
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