1 files changed, 73 insertions, 0 deletions
diff --git a/sources/fabrice/simulator/randomArray.ml b/sources/fabrice/simulator/randomArray.ml
new file mode 100644
index 0000000..4f5ddf9
--- /dev/null
+++ b/sources/fabrice/simulator/randomArray.ml
@@ -0,0 +1,73 @@
+  
+module type INTERFACE = sig
+    
+    type 'a t
+
+    val init : int -> (int -> 'a) -> 'a t
+    val length : 'a t -> int
+    val of_list : 'a list -> 'a t
+    val add : 'a t -> 'a -> unit
+    val random : 'a t -> 'a
+    val reset : 'a t -> unit  
+    val set_state : 'a t -> Random.State.t -> unit
+  end
+  
+module IMPLEMENTATION = struct
+    
+    type 'a t = {
+        mutable length : int; 
+        mutable left : int;
+        array : 'a array;
+        mutable state : Random.State.t;
+      }
+
+    let init len f =
+      let array = Array.init len f in
+      {
+        array = array;
+        length = len;
+        left = len;
+        state = Random.get_state ();
+      }
+      
+    let of_list list = 
+      let array = Array.of_list list in
+      let len = Array.length array in
+      {
+        array = array;
+        length = len;
+        left = len;
+        state = Random.get_state ();
+      }
+    
+    let length t = t.length
+    
+    let add t x = 
+      let len = t.length in
+      t.array.(len) <- x;
+      t.length <- len + 1;
+      if len = t.left then 
+        t.left <- len + 1
+    
+    let random t =
+      if t.left <= 0 then raise Not_found;
+      let pos = Random.State.int t.state t.left in
+      let tab = t.array in
+      let len = t.left-1 in 
+(*      Printf.fprintf stderr "SWAP(%d)(%d)%!" pos len; *)
+      let x = tab.(pos) in
+      tab.(pos) <- tab.(len);
+      tab.(len) <- x;
+      t.left <- len;
+      x
+      
+    let reset t = 
+      t.left <- t.length
+
+    let set_state t state = t.state <- state
+      
+  end
+
+include (IMPLEMENTATION : INTERFACE)
+  
+  
+\ No newline at end of file