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|
(**************************************************************************)
(* *)
(* OCaml *)
(* *)
(* Francois Pottier, projet Cristal, INRIA Rocquencourt *)
(* Jeremie Dimino, Jane Street Europe *)
(* *)
(* Copyright 2002 Institut National de Recherche en Informatique et *)
(* en Automatique. *)
(* *)
(* All rights reserved. This file is distributed under the terms of *)
(* the GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
exception Empty
type 'a cell =
| Nil
| Cons of { content: 'a; mutable next: 'a cell }
type 'a t = {
mutable length: int;
mutable first: 'a cell;
mutable last: 'a cell
}
let create () = {
length = 0;
first = Nil;
last = Nil
}
let clear q =
q.length <- 0;
q.first <- Nil;
q.last <- Nil
let add x q =
let cell = Cons {
content = x;
next = Nil
} in
match q.last with
| Nil ->
q.length <- 1;
q.first <- cell;
q.last <- cell
| Cons last ->
q.length <- q.length + 1;
last.next <- cell;
q.last <- cell
let push =
add
let peek q =
match q.first with
| Nil -> raise Empty
| Cons { content } -> content
let top =
peek
let take q =
match q.first with
| Nil -> raise Empty
| Cons { content; next = Nil } ->
clear q;
content
| Cons { content; next } ->
q.length <- q.length - 1;
q.first <- next;
content
let pop =
take
let copy =
let rec copy q_res prev cell =
match cell with
| Nil -> q_res.last <- prev; q_res
| Cons { content; next } ->
let res = Cons { content; next = Nil } in
begin match prev with
| Nil -> q_res.first <- res
| Cons p -> p.next <- res
end;
copy q_res res next
in
fun q -> copy { length = q.length; first = Nil; last = Nil } Nil q.first
let is_empty q =
q.length = 0
let length q =
q.length
let iter =
let rec iter f cell =
match cell with
| Nil -> ()
| Cons { content; next } ->
f content;
iter f next
in
fun f q -> iter f q.first
let fold =
let rec fold f accu cell =
match cell with
| Nil -> accu
| Cons { content; next } ->
let accu = f accu content in
fold f accu next
in
fun f accu q -> fold f accu q.first
let transfer q1 q2 =
if q1.length > 0 then
match q2.last with
| Nil ->
q2.length <- q1.length;
q2.first <- q1.first;
q2.last <- q1.last;
clear q1
| Cons last ->
q2.length <- q2.length + q1.length;
last.next <- q1.first;
q2.last <- q1.last;
clear q1
|
