(***********************************************************************)
(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the Q Public License version 1.0.               *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(function "quicksort" (lo: int hi: int a: addr)
  (if (< lo hi)
      (let (i lo
            j hi
            pivot (addraref a hi))
        (while (< i j)
          (catch
              (while 1
                (if (>= i hi) exit [])
                (if (> (addraref a i) pivot) exit [])
                (assign i (+ i 1)))
           with [])
          (catch
              (while 1
                (if (<= j lo) exit [])
                (if (< (addraref a j) pivot) exit [])
                (assign j (- j 1)))
           with [])
          (if (< i j)
              (let temp (addraref a i)
                   (addraset a i (addraref a j))
                   (addraset a j temp))
            []))
        (let temp (addraref a i)
             (addraset a i (addraref a hi))
             (addraset a hi temp))
        (app "quicksort" [lo (- i 1) a] unit)
        (app "quicksort" [(+ i 1) hi a] unit))
    []))