added congruence improvement

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9151 85f007b7-540e-0410-9357-904b9bb8a0f7

2 files changed, 12 insertions, 0 deletions

diff --git a/lib/util.ml b/lib/util.ml
index ed39934103..599e17adf4 100644
--- a/lib/util.ml
+++ b/lib/util.ml
@@ -475,6 +475,17 @@ let array_last v =
 
 let array_cons e v = Array.append [|e|] v
 
+let array_rev t = 
+  let n=Array.length t in
+    if n <=0 then () 
+    else
+      let tmp=ref t.(0) in
+      for i=0 to pred (n/2) do 
+	tmp:=t.((pred n)-i);
+	t.((pred n)-i)<- t.(i);
+	t.(i)<- !tmp
+      done
+
 let array_fold_right_i f v a =
   let rec fold a n =
     if n=0 then a
diff --git a/lib/util.mli b/lib/util.mli
index 7e6c3316f2..a5089a2de0 100644
--- a/lib/util.mli
+++ b/lib/util.mli
@@ -149,6 +149,7 @@ val array_hd : 'a array -> 'a
 val array_tl : 'a array -> 'a array
 val array_last : 'a array -> 'a
 val array_cons : 'a -> 'a array -> 'a array
+val array_rev : 'a array -> unit
 val array_fold_right_i : 
   (int -> 'b -> 'a -> 'a) -> 'b array -> 'a -> 'a
 val array_fold_left_i : (int -> 'a -> 'b -> 'a) -> 'a -> 'b array -> 'a