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add CCHashconsedSet in containers.data (set with maximal struct sharing)

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Simon Cruanes 2015-06-04 20:45:40 +02:00
parent e32e940798
commit 3d8adbaf09
3 changed files with 519 additions and 1 deletions
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@ -83,7 +83,7 @@ Library "containers_data"
Modules: CCMultiMap, CCMultiSet, CCTrie, CCFlatHashtbl, CCCache,
CCPersistentHashtbl, CCDeque, CCFQueue, CCBV, CCMixtbl,
CCMixmap, CCRingBuffer, CCIntMap, CCPersistentArray,
CCMixset
CCMixset, CCHashconsedSet
BuildDepends: bytes
FindlibParent: containers
FindlibName: data

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src/data/CCHashconsedSet.ml Normal file
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@ -0,0 +1,415 @@
(*
copyright (c) 2013-2015, simon cruanes
all rights reserved.
redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer. redistributions in binary
form must reproduce the above copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other materials provided with
the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 Hashconsed Sets} *)
(* uses "Fast Mergeable Integer Maps", Okasaki & Gill, as a hash tree.
We use big-endian trees. *)
module type ELT = sig
type t
val compare : t -> t -> int
(** Total order *)
val hash : t -> int
(** Deterministic *)
end
module type S = sig
type elt
type t
(** Set of elements *)
val empty : t
val singleton : elt -> t
val doubleton : elt -> elt -> t
val mem : elt -> t -> bool
val equal : t -> t -> bool
(** Fast equality test [O(1)] *)
val compare : t -> t -> int
(** Fast (arbitrary) comparisontest [O(1)] *)
val add : elt -> t -> t
val remove : elt -> t -> t
val cardinal : t -> int
val iter : (elt -> unit) -> t -> unit
(** Iterate on elements, in no particular order *)
val fold : (elt -> 'a -> 'a) -> t -> 'a -> 'a
(** fold on elements, in arbitrary order *)
val choose : t -> elt option
val choose_exn : t -> elt
val union : t -> t -> t
val inter : t -> t -> t
(** {2 Whole-collection operations} *)
type 'a sequence = ('a -> unit) -> unit
type 'a gen = unit -> 'a option
val add_list : t -> elt list -> t
val of_list : elt list -> t
val to_list : t -> elt list
val add_seq : t -> elt sequence -> t
val of_seq : elt sequence -> t
val to_seq : t -> elt sequence
end
module Make(E : ELT) : S with type elt = E.t = struct
type elt = E.t
type t = {
cell: cell;
id: int; (* unique hashconsing ID *)
}
and cell =
| E (* empty *)
| L of int * elt list (* leaf: sorted list of elements *)
| N of int (* common prefix *) * int (* bit switch *) * t * t
let rec eq_list_ l1 l2 = match l1, l2 with
| [], [] -> true
| [], _
| _, [] -> false
| x1 :: tl1, x2 :: tl2 ->
E.compare x1 x2 = 0 && eq_list_ tl1 tl2
let hash_pair_ a b = Hashtbl.hash (a,b)
let hash_quad_ a b c d = Hashtbl.hash (a,b,c,d)
let rec hash_list_ l = match l with
| [] -> 0xf00d
| x :: tl -> hash_pair_ x (hash_list_ tl)
(* hashconsing table *)
module Tbl = Weak.Make(struct
type t_ = t
type t = t_
let equal t1 t2 = match t1.cell, t2.cell with
| E, E -> true
| L (k1, l1), L (k2, l2) -> k1==k2 && eq_list_ l1 l2
| N (a1, b1, l1, r1), N (a2, b2, l2, r2) ->
a1==a2 && b1==b2 && l1.id == l2.id && r1.id == r2.id
| E, _
| L _, _
| N _, _ -> false
let hash t = match t.cell with
| E -> 42
| L (k, l) -> hash_pair_ k (hash_list_ l)
| N (a, b, l, r) ->
hash_quad_ a b l.id r.id
end)
let table_ = Tbl.create 4096
let id_ = ref 1
(* make a node out of a cell, with hashconsing *)
let hashcons_ cell =
let n = {cell; id= !id_} in
let n' = Tbl.merge table_ n in
if n==n' then incr id_;
n'
(* empty tree *)
let empty = hashcons_ E
let bit_is_0_ x ~bit = x land bit = 0
let mask_ x ~mask = (x lor (mask -1)) land (lnot mask)
(* low endian: let mask_ x ~mask = x land (mask - 1) *)
let is_prefix_ ~prefix y ~bit = prefix = mask_ y ~mask:bit
(* loop down until x=lowest_bit_ x *)
let rec highest_bit_naive x m =
if m = 0 then 0
else if x land m = 0 then highest_bit_naive x (m lsr 1)
else m
let highest_bit_ =
(* the highest representable 2^n *)
let max_log = 1 lsl (Sys.word_size - 2) in
fun x ->
if x > 1 lsl 20
then (* small shortcut: remove least significant 20 bits *)
let x' = x land (lnot ((1 lsl 20) -1)) in
highest_bit_naive x' max_log
else highest_bit_naive x max_log
let branching_bit_ a b = highest_bit_ (a lxor b)
let rec list_mem_ x l = match l with
| [] -> false
| y :: tl ->
match E.compare x y with
| 0 -> true
| c when c > 0 -> list_mem_ x tl
| _ -> false (* [x] cannot be in the tail, all elements are larger *)
let rec mem_rec_ k x t = match t.cell with
| E -> false
| L (k', l) when k = k' ->
list_mem_ x l
| L _ -> false
| N (prefix, m, l, r) ->
if is_prefix_ ~prefix k ~bit:m
then if bit_is_0_ k ~bit:m
then mem_rec_ k x l
else mem_rec_ k x r
else raise Not_found
let equal t1 t2 = t1.id = t2.id
let compare t1 t2 = Pervasives.compare t1.id t2.id
let mem x t = mem_rec_ (E.hash x) x t
let mk_node_ prefix switch l r = match l.cell, r.cell with
| E, _ -> r
| _, E -> l
| _ -> hashcons_ (N (prefix, switch, l, r))
let mk_leaf_ hash l = match l with
| [] -> empty
| _::_ -> hashcons_ (L (hash, l))
(* join trees t1 and t2 with prefix p1 and p2 respectively
(p1 and p2 do not overlap) *)
let join_ t1 p1 t2 p2 =
let switch = branching_bit_ p1 p2 in
let prefix = mask_ p1 ~mask:switch in
if bit_is_0_ p1 ~bit:switch
then mk_node_ prefix switch t1 t2
else (assert (bit_is_0_ p2 ~bit:switch); mk_node_ prefix switch t2 t1)
let singleton_ k x = hashcons_ (L (k, [x]))
let singleton x = singleton_ (E.hash x) x
(* insert [x] in [l], keeping [l] sorted *)
let rec insert_list_ x l = match l with
| [] -> [x]
| y :: tl ->
match E.compare x y with
| 0 -> l (* already in there *)
| c when c<0 ->
(* x<y, insert in front *)
x :: l
| _ -> y :: insert_list_ x tl
let rec add_rec_ k x t = match t.cell with
| E -> hashcons_ (L (k, [x]))
| L (k', l) ->
if k=k'
then hashcons_ (L (k, insert_list_ x l))
else join_ t k' (singleton_ k x) k
| N (prefix, switch, l, r) ->
if is_prefix_ ~prefix k ~bit:switch
then if bit_is_0_ k ~bit:switch
then hashcons_ (N(prefix, switch, add_rec_ k x l, r))
else hashcons_ (N(prefix, switch, l, add_rec_ k x r))
else join_ (singleton_ k x) k t prefix
let add x t = add_rec_ (E.hash x) x t
(*$Q & ~count:20
Q.(list int) (fun l -> \
let module S = Make(CCInt) in \
let m = S.of_list l in \
List.for_all (fun x -> S.mem x m) l)
*)
let rec remove_list_ x l = match l with
| [] -> []
| y :: tl ->
match E.compare x y with
| 0 -> tl (* eliminate *)
| c when c<0 -> l (* cannot be in [l] *)
| _ -> y :: remove_list_ x tl
let rec remove_rec_ k x t = match t.cell with
| E -> empty
| L (k', l) when k=k' ->
mk_leaf_ k (remove_list_ x l)
| L _ -> t (* preserve *)
| N (prefix, switch, l, r) ->
if is_prefix_ ~prefix k ~bit:switch
then if bit_is_0_ k ~bit:switch
then mk_node_ prefix switch (remove_rec_ k x l) r
else mk_node_ prefix switch l (remove_rec_ k x r)
else t (* not present *)
let remove x l = remove_rec_ (E.hash x) x l
let doubleton v1 v2 = add v1 (singleton v2)
let rec iter f t = match t.cell with
| E -> ()
| L (_, v) -> List.iter f v
| N (_, _, l, r) -> iter f l; iter f r
let rec fold f t acc = match t.cell with
| E -> acc
| L (_, l) -> List.fold_right f l acc
| N (_, _, l, r) ->
let acc = fold f l acc in
fold f r acc
let cardinal t = fold (fun _ n -> n+1) t 0
let rec choose_exn t = match t.cell with
| E -> raise Not_found
| L (_, []) -> assert false
| L (_, x :: _) -> x
| N (_, _, l, _) -> choose_exn l
let choose t =
try Some (choose_exn t)
with Not_found -> None
let rec union_list_ l1 l2 = match l1, l2 with
| [], _ -> l2
| _, [] -> l1
| x1 :: tl1, x2 :: tl2 ->
match E.compare x1 x2 with
| 0 -> x1 :: union_list_ tl1 tl2
| c when c<0 -> x1 :: union_list_ tl1 l2
| _ -> x2 :: union_list_ l1 tl2
(* add elements of [l], all of which have hash [k], to [t] *)
let add_list_hash_ k l t =
List.fold_left
(fun t x -> add_rec_ k x t)
t l
let rec union a b = match a.cell, b.cell with
| E, _ -> b
| _, E -> a
| L (k1, l1), L(k2, l2) when k1==k2 ->
mk_leaf_ k1 (union_list_ l1 l2) (* merge leaves *)
| L (k, l), _ -> add_list_hash_ k l b
| _, L (k, l) -> add_list_hash_ k l a
| N (p1, m1, l1, r1), N (p2, m2, l2, r2) ->
if p1 = p2 && m1 = m2
then mk_node_ p1 m1 (union l1 l2) (union r1 r2)
else if m1 < m2 && is_prefix_ ~prefix:p2 p1 ~bit:m1
then if bit_is_0_ p2 ~bit:m1
then hashcons_ (N (p1, m1, union l1 b, r1))
else hashcons_ (N (p1, m1, l1, union r1 b))
else if m1 > m2 && is_prefix_ ~prefix:p1 p2 ~bit:m2
then if bit_is_0_ p1 ~bit:m2
then hashcons_ (N (p2, m2, union l2 a, r2))
else hashcons_ (N (p2, m2, l2, union r2 a))
else join_ a p1 b p2
(*$Q
Q.(list int) (fun l -> \
let module S = Make(CCInt) in \
let s = S.of_list l in S.equal s (S.union s s))
*)
let rec inter_list_ l1 l2 = match l1, l2 with
| [], _
| _, [] -> []
| x1 :: tl1, x2 :: tl2 ->
match E.compare x1 x2 with
| 0 -> x1 :: inter_list_ tl1 tl2
| c when c<0 -> inter_list_ tl1 l2
| _ -> inter_list_ l1 tl2
let rec inter a b = match a.cell, b.cell with
| E, _ | _, E -> empty
| L (k1, l1), L (k2, l2) when k1==k2 ->
mk_leaf_ k1 (inter_list_ l1 l2)
| L _, _
| _, L _ -> empty
| N (p1, m1, l1, r1), N (p2, m2, l2, r2) ->
if p1 = p2 && m1 = m2
then mk_node_ p1 m1 (inter l1 l2) (inter r1 r2)
else if m1 < m2 && is_prefix_ ~prefix:p2 p1 ~bit:m1
then if bit_is_0_ p2 ~bit:m1
then inter l1 b
else inter r1 b
else if m1 > m2 && is_prefix_ ~prefix:p1 p2 ~bit:m2
then if bit_is_0_ p1 ~bit:m2
then inter l2 a
else inter r2 a
else empty
(*$Q
Q.(list int) (fun l -> \
let module S = Make(CCInt) in \
let s = S.of_list l in S.equal s (S.inter s s))
*)
(* TODO: difference *)
(** {2 Whole-collection operations} *)
type 'a sequence = ('a -> unit) -> unit
type 'a gen = unit -> 'a option
let add_list t l = List.fold_left (fun t x -> add x t) t l
let of_list l = add_list empty l
let to_list t = fold (fun x l -> x:: l) t []
(*$Q
Q.(list int) (fun l -> \
let module S = Make(CCInt) in \
S.of_list l |> S.cardinal = List.length l)
*)
let add_seq t seq =
let t = ref t in
seq (fun x -> t := add x !t);
!t
let of_seq seq = add_seq empty seq
let to_seq t yield = iter yield t
end

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src/data/CCHashconsedSet.mli Normal file
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@ -0,0 +1,103 @@
(*
copyright (c) 2013-2015, simon cruanes
all rights reserved.
redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer. redistributions in binary
form must reproduce the above copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other materials provided with
the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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 Hashconsed Sets}
Sets are hashconsed, so that set equality is physical equality. Some
sub-structure that is common to several sets is also perfectly shared.
{b status: unstable}
@since NEXT_RELEASE *)
module type ELT = sig
type t
val compare : t -> t -> int
(** Total order *)
val hash : t -> int
(** Deterministic *)
end
module type S = sig
type elt
type t
(** Set of elements *)
val empty : t
val singleton : elt -> t
val doubleton : elt -> elt -> t
val mem : elt -> t -> bool
val equal : t -> t -> bool
(** Fast equality test [O(1)] *)
val compare : t -> t -> int
(** Fast (arbitrary) comparisontest [O(1)] *)
val add : elt -> t -> t
val remove : elt -> t -> t
val cardinal : t -> int
val iter : (elt -> unit) -> t -> unit
(** Iterate on elements, in no particular order *)
val fold : (elt -> 'a -> 'a) -> t -> 'a -> 'a
(** fold on elements, in arbitrary order *)
val choose : t -> elt option
val choose_exn : t -> elt
val union : t -> t -> t
val inter : t -> t -> t
(** {2 Whole-collection operations} *)
type 'a sequence = ('a -> unit) -> unit
type 'a gen = unit -> 'a option
val add_list : t -> elt list -> t
val of_list : elt list -> t
val to_list : t -> elt list
val add_seq : t -> elt sequence -> t
val of_seq : elt sequence -> t
val to_seq : t -> elt sequence
end
module Make(E : ELT) : S with type elt = E.t