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-- CC70001.A

--

--                             Grant of Unlimited Rights

--

--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,

--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained

--     unlimited rights in the software and documentation contained herein.

--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making

--     this public release, the Government intends to confer upon all

--     recipients unlimited rights  equal to those held by the Government.

--     These rights include rights to use, duplicate, release or disclose the

--     released technical data and computer software in whole or in part, in

--     any manner and for any purpose whatsoever, and to have or permit others

--     to do so.

--

--                                    DISCLAIMER

--

--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR

--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED

--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE

--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE

--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A

--     PARTICULAR PURPOSE OF SAID MATERIAL.

--*

--

-- OBJECTIVE:

--      Check that the template for a generic formal package may be a child

--      package, and that a child instance which is an instance of the

--      template may be passed as an actual to the formal package. Check that

--      the visible part of the generic formal package includes the first list

--      of basic declarative items of the package specification.

--

-- TEST DESCRIPTION:

--      Declare a list abstraction in a generic package which manages lists of

--      elements of any nonlimited type. Declare a generic child package of

--      this package which defines additional list operations. Declare a

--      generic subprogram which operates on lists of elements of discrete

--      types. Provide the generic subprogram with three formal parameters:

--      (1) a formal discrete type which represents a list element type, (2)

--      a generic formal package with the parent list generic as template, and

--      (3) a generic formal package with the child list generic as template.

--      Use the formal discrete type as the generic formal actual part for the

--      parent formal package. In the main program, declare an instance of

--      parent, then declare an instance of the child which is itself a child

--      the parent's instance. Pass these instances as actuals to the generic

--      subprogram instance.

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--      05 Nov 95   SAIC    ACVC 2.0.1 fixes: Corrected syntax of formal

--                          package declaration.

--      27 Feb 97   PWB.CTA Added an elaboration pragma.

--!

generic

   type Element_Type is private;  -- List elems may be of any nonlimited type.

package CC70001_0 is              -- List abstraction.

   type List_Type is limited private;

   -- Return true if current element is last in the list.

   function End_Of_List (L : List_Type) return Boolean;

   -- Set "current" pointer to first list element.

   procedure Reset (L : in out List_Type);

private

   type Node_Type;

   type Node_Pointer is access Node_Type;

   type Node_Type is record

      Item : Element_Type;

      Next : Node_Pointer;

   end record;

   type List_Type is record

      First   : Node_Pointer;

      Current : Node_Pointer;

      Last    : Node_Pointer;

   end record;

end CC70001_0;

     --==================================================================--

package body CC70001_0 is

   function End_Of_List (L : List_Type) return Boolean is

   begin

      return (L.Current = null);

   end End_Of_List;

   procedure Reset (L : in out List_Type) is

   begin

      L.Current := L.First;                 -- Set "current" pointer to first

   end Reset;                               -- list element.

end CC70001_0;

     --==================================================================--

-- Child must be generic since parent is generic. A formal parameter for

-- "element type" can not be provided here, because then the type of list

-- element assumed by these new operations would be different from that

-- defined by the list type declared in the parent.

generic

package CC70001_0.CC70001_1 is    -- Additional list operations.

   -- Read from current element and advance "current" pointer.

   procedure Read_Element (L : in out List_Type; E : out Element_Type);

   -- Write to current element and advance "current" pointer.

   procedure Write_Element (L : in out List_Type; E : in Element_Type);

   -- Add element to end of list.

   procedure Add_Element (L : in out List_Type; E : in Element_Type);

end CC70001_0.CC70001_1;

     --==================================================================--

package body CC70001_0.CC70001_1 is

   procedure Read_Element (L : in out List_Type; E : out Element_Type) is

   begin

      -- ... Error-checking code omitted for brevity.

      E         := L.Current.Item;       -- Retrieve current element.

      L.Current := L.Current.Next;       -- Advance "current" pointer.

   end Read_Element;

   procedure Write_Element (L : in out List_Type; E : in Element_Type) is

   begin

      -- ... Error-checking code omitted for brevity.

      L.Current.Item := E;               -- Write to current element.

      L.Current      := L.Current.Next;  -- Advance "current" pointer.

   end Write_Element;

   procedure Add_Element (L : in out List_Type; E : in Element_Type) is

      New_Node : Node_Pointer := new Node_Type'(E, null);

   begin

      if L.First = null then             -- No elements in list, so add new

         L.First := New_Node;            -- element at beginning of list.

      else

         L.Last.Next := New_Node;        -- Add new element at end of list.

      end if;

      L.Last := New_Node;                -- Set last-in-list pointer.

   end Add_Element;

end CC70001_0.CC70001_1;

     --==================================================================--

with CC70001_0.CC70001_1;  -- Generic list abstraction + additional operations.

generic

   -- Import the list abstraction defined in CC70001_0, as well as the

   -- additional operations defined in CC70001_0.CC70001_1. Declare a formal

   -- discrete type. Restrict this generic procedure to operate only on lists

   -- of discrete elements by passing the formal discrete type as an actual

   -- parameter to the formal (parent) package.

   type Elem_Type is (<>);                  -- Discrete types only.

   with package List_Mgr is new CC70001_0 (Elem_Type);

   with package List_Ops is new List_Mgr.CC70001_1 (<>);

procedure CC70001_2 (L : in out List_Mgr.List_Type);

     --==================================================================--

procedure CC70001_2 (L : in out List_Mgr.List_Type) is

begin

   List_Mgr.Reset (L);

   while not List_Mgr.End_Of_List (L) loop

      List_Ops.Write_Element (L, Elem_Type'First);

   end loop;

end CC70001_2;

     --==================================================================--

package CC70001_3 is

   type Points is range 0 .. 10;

   -- ... Various other types used by the application.

end CC70001_3;

-- No body for CC70001_3;

     --==================================================================--

-- Declare instances of the generic list packages for the discrete type.

-- In order to establish that the type passed as an actual to the parent

-- generic (CC70001_0) is the one utilized by the child generic (CC70001_1),

-- the instance of the child must itself be declared as a child of the

-- instance of the parent. Since only library units may have or be children,

-- both instances must be library units.

with CC70001_0;            -- Generic list abstraction.

with CC70001_3;            -- Package containing discrete type declaration.

pragma Elaborate (CC70001_0);

package CC70001_4 is new CC70001_0 (CC70001_3.Points);

with CC70001_0.CC70001_1;  -- Generic extension to list abstraction.

with CC70001_4;

package CC70001_4.CC70001_5 is new CC70001_4.CC70001_1;

     --==================================================================--

with CC70001_2;            -- Generic "zeroing" op for lists of discrete types.

with CC70001_3;            -- Types for application.

with CC70001_4.CC70001_5;  -- Discrete list abstraction + additional ops.

with Report;

procedure CC70001 is

   package Lists_Of_Scores renames CC70001_4;

   package Score_Ops       renames CC70001_4.CC70001_5;

   Scores : Lists_Of_Scores.List_Type;                -- List of points.

   procedure Reset_All_Scores is new CC70001_2        -- Operation on lists of

     (Elem_Type => CC70001_3.Points,                  -- points.

      List_Mgr  => Lists_Of_Scores,

      List_Ops  => Score_Ops);

   -- Begin test code declarations: -----------------------

   type TC_Score_Array is array (1 .. 3) of CC70001_3.Points;

   TC_Initial_Values : constant TC_Score_Array := (2, 4, 6);

   TC_Final_Values   : constant TC_Score_Array := (0, 0, 0);

   TC_Correct_Initial_Values : Boolean := False;

   TC_Correct_Final_Values   : Boolean := False;

   procedure TC_Initialize_List (L : in out Lists_of_Scores.List_Type) is

   begin                                  -- Initial list contains 3 scores

      for I in TC_Score_Array'Range loop  -- with the values 2, 4, and 6.

         Score_Ops.Add_Element (L, TC_Initial_Values(I));

      end loop;

   end TC_Initialize_List;

   procedure TC_Verify_List (L        : in out Lists_of_Scores.List_Type;

                             Expected : in     TC_Score_Array;

                             OK       :    out Boolean) is

      Actual : TC_Score_Array;

   begin                                  -- Verify that all scores have been

      Lists_of_Scores.Reset (L);          -- set to zero.

      for I in TC_Score_Array'Range loop

         Score_Ops.Read_Element (L, Actual(I));

      end loop;

      OK := (Actual = Expected);

   end TC_Verify_List;

   -- End test code declarations. -------------------------

begin

   Report.Test ("CC70001", "Check that the template for a generic formal "   &

                "package may be a child package, and that a child instance " &

                "which is an instance of the template may be passed as an "  &

                "actual to the formal package. Check that the visible part " &

                "of the generic formal package includes the first list of "  &

                "basic declarative items of the package specification");

   TC_Initialize_List (Scores);

   TC_Verify_List (Scores, TC_Initial_Values, TC_Correct_Initial_Values);

   if not TC_Correct_Initial_Values then

      Report.Failed ("List contains incorrect initial values");

   end if;

   Reset_All_Scores (Scores);

   TC_Verify_List (Scores, TC_Final_Values, TC_Correct_Final_Values);

   if not TC_Correct_Final_Values then

      Report.Failed ("List contains incorrect final values");

   end if;

   Report.Result;

end CC70001;