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(* copied from https://github.com/leque/ocaml-diff.git and renamed from "diff.ml" *)
(*
* Copyright (C) 2016 OOHASHI Daichi
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*)
type 'a common =
[ `Common of int * int * 'a ]
type 'a edit =
[ `Added of int * 'a
| `Removed of int * 'a
| 'a common
]
module type SeqType = sig
type t
type elem
val get : t -> int -> elem
val length : t -> int
end
module type S = sig
type t
type elem
val lcs :
?equal:(elem -> elem -> bool) ->
t -> t -> elem common list
val diff :
?equal:(elem -> elem -> bool) ->
t -> t -> elem edit list
val fold_left :
?equal:(elem -> elem -> bool) ->
f:('a -> elem edit -> 'a) ->
init:'a ->
t -> t -> 'a
val iter :
?equal:(elem -> elem -> bool) ->
f:(elem edit -> unit) ->
t -> t -> unit
end
module Make(M : SeqType) : (S with type t = M.t and type elem = M.elem) = struct
type t = M.t
type elem = M.elem
let lcs ?(equal = (=)) a b =
let n = M.length a in
let m = M.length b in
let mn = m + n in
let sz = 2 * mn + 1 in
let vd = Array.make sz 0 in
let vl = Array.make sz 0 in
let vr = Array.make sz [] in
let get v i = Array.get v (i + mn) in
let set v i x = Array.set v (i + mn) x in
let finish () =
let rec loop i maxl r =
if i > mn then
List.rev r
else if get vl i > maxl then
loop (i + 1) (get vl i) (get vr i)
else
loop (i + 1) maxl r
in loop (- mn) 0 []
in
if mn = 0 then
[]
else
(* For d <- 0 to mn Do *)
let rec dloop d =
assert (d <= mn);
(* For k <- -d to d in steps of 2 Do *)
let rec kloop k =
if k > d then
dloop @@ d + 1
else
let x, l, r =
if k = -d || (k <> d && get vd (k - 1) < get vd (k + 1)) then
get vd (k + 1), get vl (k + 1), get vr (k + 1)
else
get vd (k - 1) + 1, get vl (k - 1), get vr (k - 1)
in
let x, y, l, r =
let rec xyloop x y l r =
if x < n && y < m && equal (M.get a x) (M.get b y) then
xyloop (x + 1) (y + 1) (l + 1) (`Common(x, y, M.get a x) :: r)
else
x, y, l, r
in xyloop x (x - k) l r
in
set vd k x;
set vl k l;
set vr k r;
if x >= n && y >= m then
(* Stop *)
finish ()
else
kloop @@ k + 2
in kloop @@ -d
in dloop 0
let fold_left ?(equal = (=)) ~f ~init a b =
let ff x y = f y x in
let fold_map f g x from to_ init =
let rec loop i init =
if i >= to_ then
init
else
loop (i + 1) (f (g i @@ M.get x i) init)
in loop from init
in
let added i x = `Added (i, x) in
let removed i x = `Removed (i, x) in
let rec loop cs apos bpos init =
match cs with
| [] ->
init
|> fold_map ff removed a apos (M.length a)
|> fold_map ff added b bpos (M.length b)
| `Common (aoff, boff, _) as e :: rest ->
init
|> fold_map ff removed a apos aoff
|> fold_map ff added b bpos boff
|> ff e
|> loop rest (aoff + 1) (boff + 1)
in loop (lcs ~equal a b) 0 0 init
let diff ?(equal = (=)) a b =
fold_left ~equal ~f:(fun xs x -> x::xs) ~init:[] a b
let iter ?(equal = (=)) ~f a b =
fold_left a b
~equal
~f:(fun () x -> f x)
~init:()
end