c640001.a

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-- C640001.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 prefix of a subprogram call with an actual parameter
--      part may be an implicit dereference of an access-to-subprogram value.
--      Check that, for an access-to-subprogram type whose designated profile
--      contains parameters of a tagged generic formal type, an access-to-
--      subprogram value may designate dispatching and non-dispatching
--      operations, and that dereferences of such a value call the appropriate
--      subprogram.
--
-- TEST DESCRIPTION:
--      The test declares a tagged type (Table) with a dispatching operation
--      (Clear), as well as a derivative (Table2) which overrides that
--      operation. A subprogram with the same name and profile as Clear is
--      declared in a separate package -- it is therefore not a dispatching
--      operation of Table. For the purposes of the test, each version of Clear
--      modifies the components of its parameter in a unique way.
--
--      Additionally, an operation (Reset) of type Table is declared which
--      makes a re-dispatching call to Clear, i.e.,
--
--         procedure Reset (A: in out Table) is
--         begin
--            ...
--            Clear (Table'Class(A));  -- Re-dispatch based on tag of actual.
--            ...
--         end Reset;   
--
--      An access-to-subprogram type is declared within a generic package,
--      with a designated profile which declares a parameter of a generic
--      formal tagged private type.
--
--      The generic is instantiated with type Table. The instance defines an
--      array of access-to-subprogram values (which represents a table of
--      operations to be performed sequentially on a single operand).
--      Access values designating the dispatching version of Clear, the
--      non-dispatching version of Clear, and Reset (which re-dispatches to
--      Clear) are placed in this array.
--
--      In the instance, each subprogram in the array is called by implicitly
--      dereferencing the corresponding access value. For the dispatching and
--      non-dispatching versions of Clear, the actual parameter passed is of
--      type Table. For Reset, the actual parameter passed is a view conversion
--      of an object of type Table2 to type Table, i.e., Table(Table2_Obj).
--      Since the tag of the operand never changes, the call to Clear within
--      Reset should execute Table2's version of Clear.
--
--      The main program verifies that the appropriate version of Clear is
--      called in each case, by checking that the components of the actual are
--      updated as expected.
--
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--
--!

package C640001_0 is

   -- Data type artificial for testing purposes.

   Row_Len : constant := 10;

   T : constant Boolean := True;
   F : constant Boolean := False;

   type Row_Type is array (1 .. Row_Len) of Boolean;

   function Is_True  (A : in Row_Type) return Boolean;
   function Is_False (A : in Row_Type) return Boolean;


   Init : constant Row_Type := (T, F, T, F, T, F, T, F, T, F);

   type Table is tagged record                  -- Tagged type.
      Row1 : Row_Type := Init;
      Row2 : Row_Type := Init;
   end record;

   procedure Clear (A : in out Table);          -- Dispatching operation.

   procedure Reset (A : in out Table);          -- Re-dispatching operation.

   -- ...Other operations.


   type Table2 is new Table with null record;   -- Extension of Table (but
                                                -- structurally identical).

   procedure Clear (A : in out Table2);         -- Overrides parent's op.

   -- ...Other operations.


end C640001_0;


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


package body C640001_0 is

   function Is_True (A : in Row_Type) return Boolean is
   begin
      for I in A'Range loop
         if A(I) /= True then                  -- Return true if all elements
            return False;                      -- of A are True.
         end if;
      end loop;
      return True;
   end Is_True;


   function Is_False (A : in Row_Type) return Boolean is
   begin
      return A = Row_Type'(others => False);   -- Return true if all elements
   end Is_False;                               -- of A are False.


   procedure Clear (A : in out Table) is
   begin
      for I in Row_Type'Range loop             -- This version of Clear sets
         A.Row1(I) := False;                   -- the elements of Row1 only
      end loop;                                -- to False.
   end Clear;


   procedure Reset (A : in out Table) is
   begin
      Clear (Table'Class(A));                  -- Redispatch to appropriate
      -- ... Other "reset" activities.         -- version of Clear.
   end Reset;


   procedure Clear (A : in out Table2) is
   begin
      for I in Row_Type'Range loop             -- This version of Clear sets
         A.Row1(I) := True;                    -- the elements of Row1 only
      end loop;                                -- to True.
   end Clear;


end C640001_0;


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


with C640001_0;
package C640001_1 is

   procedure Clear (T : in out C640001_0.Table);  -- Non-dispatching operation.

end C640001_1;


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


package body C640001_1 is

   procedure Clear (T : in out C640001_0.Table) is
   begin
      for I in C640001_0.Row_Type'Range loop   -- This version of Clear sets
         T.Row2(I) := True;                    -- the elements of Row2 only
      end loop;                                -- to True.
   end Clear;

end C640001_1;


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


-- This unit represents a support package for table-driven processing of
-- data objects. Process_Operand performs a set of operations are performed
-- sequentially on a single operand. Note that parameters are provided to
-- specify which subset of operations in the operations table are to be
-- performed (ordinarily these might be omitted, but the test requires that
-- each operation be called individually for a single operand).

generic
   type Tag is tagged private;
package C640001_2 is

   type Proc_Ptr is access procedure (P: in out Tag);

   type Op_List is private;

   procedure Add_Op (Op   : in     Proc_Ptr;                -- Add operation to
                     List : in out Op_List);                -- to list of ops.

   procedure Process_Operand (Operand  : in out Tag;        -- Execute a subset
                              List     : in     Op_List;    -- of a list of
                              First_Op : in     Positive;   -- operations using
                              Last_Op  : in     Positive);  -- a given operand.

   -- ...Other operations.

private
   type Op_Array is array (1 .. 3) of Proc_Ptr;

   type Op_List is record
      Top : Natural := 0;
      Ops : Op_Array;
   end record;
end C640001_2;


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


package body C640001_2 is

   procedure Add_Op (Op   : in     Proc_Ptr;
                     List : in out Op_List) is
   begin
      List.Top := List.Top + 1;  -- Artificial; no Constraint_Error protection.
      List.Ops(List.Top) := Op;
   end Add_Op;


   procedure Process_Operand (Operand  : in out Tag;
                              List     : in     Op_List;
                              First_Op : in     Positive;
                              Last_Op  : in     Positive) is
   begin
      for I in First_Op .. Last_Op loop
         List.Ops(I)(Operand);       -- Implicit dereference of an
      end loop;                      -- access-to-subprogram value.
   end Process_Operand;

end C640001_2;


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


with C640001_0;
with C640001_1;
with C640001_2;

with Report;
procedure C640001 is

   package Table_Support is new C640001_2 (C640001_0.Table);

   Sub_Ptr   : Table_Support.Proc_Ptr;
   My_List   : Table_Support.Op_List;
   My_Table1 : C640001_0.Table;             -- Initial values of both Row1 &
                                            -- Row2 are (T,F,T,F,T,F,T,F,T,F).
   My_Table2 : C640001_0.Table2;            -- Initial values of both Row1 &
                                            -- Row2 are (T,F,T,F,T,F,T,F,T,F).
begin
   Report.Test ("C640001", "Check that, for an access-to-subprogram type " &
                           "whose designated profile contains parameters " &
                           "of a tagged generic formal type, an access-" &
                           "to-subprogram value may designate dispatching " &
                           "and non-dispatching operations");

   --
   -- Add subprogram access values to list:
   --

   Sub_Ptr := C640001_0.Clear'Access;       -- Designates dispatching op.
   Table_Support.Add_Op (Sub_Ptr, My_List); -- (1st operation on My_List).

   Sub_Ptr := C640001_1.Clear'Access;       -- Designates non-dispatching op.
   Table_Support.Add_Op (Sub_Ptr, My_List); -- (2nd operation on My_List).

   Sub_Ptr := C640001_0.Reset'Access;       -- Designates re-dispatching op.
   Table_Support.Add_Op (Sub_Ptr, My_List); -- (3rd operation on My_List).


   --
   -- Call dispatching operation:
   --

   Table_Support.Process_Operand (My_Table1, My_List, 1, 1);   -- Call 1st op.
   
   if not C640001_0.Is_False (My_Table1.Row1) then
      Report.Failed ("Wrong result after calling dispatching operation");
   end if;


   --
   -- Call non-dispatching operation:
   --

   Table_Support.Process_Operand (My_Table1, My_List, 2, 2);   -- Call 2nd op.
   
   if not C640001_0.Is_True (My_Table1.Row2) then
      Report.Failed ("Wrong result after calling non-dispatching operation");
   end if;


   --
   -- Call re-dispatching operation:
   --

   Table_Support.Process_Operand (C640001_0.Table(My_Table2),  -- View conv.
                                  My_List, 3, 3);              -- Call 3rd op.
   
   if not C640001_0.Is_True (My_Table2.Row1) then
      Report.Failed ("Wrong result after calling re-dispatching operation");
   end if;


   Report.Result;
end C640001;