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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT LIBRARY COMPONENTS                          --

--                                                                          --

--              ADA.CONTAINERS.GENERIC_CONSTRAINED_ARRAY_SORT               --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 2004-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- This unit was originally developed by Matthew J Heaney.                  --

------------------------------------------------------------------------------

--  This algorithm was adapted from GNAT.Heap_Sort_G (see g-hesorg.ad[sb])

with System;

procedure Ada.Containers.Generic_Constrained_Array_Sort

  (Container : in out Array_Type)

is

   type T is range System.Min_Int .. System.Max_Int;

   function To_Index (J : T) return Index_Type;

   pragma Inline (To_Index);

   procedure Sift (S : T);

   A : Array_Type renames Container;

   --------------

   -- To_Index --

   --------------

   function To_Index (J : T) return Index_Type is

      K : constant T'Base := Index_Type'Pos (A'First) + J - T'(1);

   begin

      return Index_Type'Val (K);

   end To_Index;

   Max  : T := A'Length;

   Temp : Element_Type;

   ----------

   -- Sift --

   ----------

   procedure Sift (S : T) is

      C   : T := S;

      Son : T;

   begin

      loop

         Son := 2 * C;

         exit when Son > Max;

         declare

            Son_Index : Index_Type := To_Index (Son);

         begin

            if Son < Max then

               if A (Son_Index) < A (Index_Type'Succ (Son_Index)) then

                  Son := Son + 1;

                  Son_Index := Index_Type'Succ (Son_Index);

               end if;

            end if;

            A (To_Index (C)) := A (Son_Index);  -- Move (Son, C);

         end;

         C := Son;

      end loop;

      while C /= S loop

         declare

            Father : constant T := C / 2;

         begin

            if A (To_Index (Father)) < Temp then           -- Lt (Father, 0)

               A (To_Index (C)) := A (To_Index (Father));  -- Move (Father, C)

               C := Father;

            else

               exit;

            end if;

         end;

      end loop;

      A (To_Index (C)) := Temp; -- Move (0, C);

   end Sift;

--  Start of processing for Generic_Constrained_Array_Sort

begin

   for J in reverse 1 .. Max / 2 loop

      Temp := Container (To_Index (J)); --  Move (J, 0);

      Sift (J);

   end loop;

   while Max > 1 loop

      Temp := A (To_Index (Max));         --  Move (Max, 0);

      A (To_Index (Max)) := A (A'First);  --  Move (1, Max);

      Max := Max - 1;

      Sift (1);

   end loop;

end Ada.Containers.Generic_Constrained_Array_Sort;