From adfe52bf1f11862d67a5e5ad8486dd278c87fdc1 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 26 Oct 2022 23:03:36 -0400
Subject: [PATCH] utils

---
 src/util/Util.ml  | 7 +++++++
 src/util/Util.mli | 1 +
 2 files changed, 8 insertions(+)

diff --git a/src/util/Util.ml b/src/util/Util.ml
index 678317b2..8513f088 100644
--- a/src/util/Util.ml
+++ b/src/util/Util.ml
@@ -44,6 +44,13 @@ let lazy_map2 f x y =
     (let (lazy x) = x and (lazy y) = y in
      f x y)
 
+let[@inline] swap_array a i j : unit =
+  if i != j then (
+    let tmp = a.(i) in
+    a.(i) <- a.(j);
+    a.(j) <- tmp
+  )
+
 let setup_gc () =
   let g = Gc.get () in
   Gc.set
diff --git a/src/util/Util.mli b/src/util/Util.mli
index 5b785698..2353ed04 100644
--- a/src/util/Util.mli
+++ b/src/util/Util.mli
@@ -17,6 +17,7 @@ val array_to_list_map : ('a -> 'b) -> 'a array -> 'b list
 val lazy_map : ('a -> 'b) -> 'a lazy_t -> 'b lazy_t
 val lazy_map2 : ('a -> 'b -> 'c) -> 'a lazy_t -> 'b lazy_t -> 'c lazy_t
 val array_iteri2 : f:(int -> 'a -> 'b -> unit) -> 'a array -> 'b array -> unit
+val swap_array : 'a array -> int -> int -> unit
 
 val setup_gc : unit -> unit
 (** Change parameters of the GC *)