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(*
* Copyright (C) 2006-2009 Citrix Systems Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*)
type 'a t = { size: int; mutable current: int; data: 'a array; }
(** create a ring structure with size record. records inited to initval *)
let make size initval =
{ size = size; current = size - 1; data = Array.create size initval; }
(** length of the ring *)
let length ring = ring.size
(** push into the ring one element *)
let push ring e =
ring.current <- ring.current + 1;
if ring.current = ring.size then
ring.current <- 0;
ring.data.(ring.current) <- e
(** get the ith old element from the ring *)
let peek ring i =
if i >= ring.size then
raise (Invalid_argument "peek: index");
let index =
let offset = ring.current - i in
if offset >= 0 then offset else ring.size + offset in
ring.data.(index)
(** get the top element of the ring *)
let top ring = ring.data.(ring.current)
(** iterate over nb element of the ring, starting from the top *)
let iter_nb ring f nb =
if nb > ring.size then
raise (Invalid_argument "iter_nb: nb");
(* FIXME: OPTIMIZE ME with 2 Array.iter ? *)
for i = 0 to nb - 1
do
f (peek ring i)
done
(** iter directly on all element without using the index *)
let raw_iter ring f =
Array.iter f ring.data
(** iterate over all element of the ring, starting from the top *)
let iter ring f = iter_nb ring f (ring.size)
(** get array of latest nb value *)
let get_nb ring nb =
if nb > ring.size then
raise (Invalid_argument "get_nb: nb");
let a = Array.create nb (top ring) in
for i = 1 to nb - 1
do
(* FIXME: OPTIMIZE ME with 2 Array.blit *)
a.(i) <- peek ring i
done;
a
let get ring = get_nb ring (ring.size)
|
