[paparazzi-commits] [4863] add a polymorphic shifter

[Pascal Brisset]

Revision: 4863
          http://svn.sv.gnu.org/viewvc/?view=rev&root=paparazzi&revision=4863
Author:   hecto
Date:     2010-04-22 15:38:02 +0000 (Thu, 22 Apr 2010)
Log Message:
-----------
 add a polymorphic shifter

Modified Paths:
--------------
    paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.ml
    paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.mli

Modified: paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.ml
===================================================================
--- paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.ml        2010-04-22 14:40:37 UTC 
(rev 4862)
+++ paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.ml        2010-04-22 15:38:02 UTC 
(rev 4863)
@@ -67,3 +67,12 @@
   fun () ->
     x := k *. !x +. normal 0. sigma;
     !x
+
+let shifter = fun n default ->
+  let a = Array.create n default
+  and i = ref 0 in
+  fun new_value ->
+    let old_value = a.(!i) in
+    a.(!i) <- new_value;
+    i := (!i + 1) mod n;
+    old_value

Modified: paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.mli
===================================================================
--- paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.mli       2010-04-22 14:40:37 UTC 
(rev 4862)
+++ paparazzi3/trunk/sw/lib/ocaml/ocaml_tools.mli       2010-04-22 15:38:02 UTC 
(rev 4863)
@@ -46,3 +46,7 @@
 (* [make_1st_order_noise_generator ?init k sigma] Returns a generator
    initialized to [init], damped by [k] with a variation of stdev [sigma].
    0 < [k] < 1 . x_n+1 <- k x_n + normal 0 sigma . *)
+
+val shifter : int -> 'a -> ('a -> 'a)
+(* [shifter size init] Returns a shift register containing [size] values
+   initialized to [init] *)