c3a0001.a

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-- C3A0001.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 access to subprogram type can be used to select and
--      invoke functions with appropriate arguments dynamically.
--
-- TEST DESCRIPTION:
--      Declare an access to function type in a package specification.  
--      Declare three different sine functions that can be referred to by 
--      the access to function type.  
--      
--      In the main program, call each function indirectly by dereferencing 
--      the access value.
--
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--
--!

package C3A0001_0 is
   
   TC_Call_Tag : Natural := 0;

   -- Type accesses to any sine function
   type Sine_Function_Ptr is access function   
      (Angle : in Float) return Float;

-- Three 'Sine' functions that model an application situation in which
-- one function might be chosen when speed is important, another (using
-- a different algorithm) might be chosen when accuracy is important,
-- and so on.

   function Sine_Calc_Fast  (Angle : in Float) return Float;         

   function Sine_Calc_Acc   (Angle : in Float) return Float;        

   function Sine_Calc_Table (Angle : in Float) return Float;        

end C3A0001_0;


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


package body C3A0001_0 is

   function Sine_Calc_Fast (Angle : in Float) return Float is
   begin
      TC_Call_Tag := 1;
      return 1.0;
   end Sine_Calc_Fast;


   function Sine_Calc_Acc (Angle : in Float) return Float is
   begin
      TC_Call_Tag := 2;
      return 0.0;
   end Sine_Calc_Acc;


   function Sine_Calc_Table (Angle : in Float) return Float is
   begin
      TC_Call_Tag := 3;
      return -1.0;         
   end Sine_Calc_Table;

end C3A0001_0;

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

with Report;
with C3A0001_0;

procedure C3A0001 is

   Sine_Access : C3A0001_0.Sine_Function_Ptr;
   X, Theta    : Float := 0.0;

begin

   Report.Test ("C3A0001", "Check that access to subprogram can be " &
                "used to select and invoke an operation with " &
                "appropriate arguments dynamically");

   Sine_Access := C3A0001_0.Sine_Calc_Fast'Access;

   -- Invoking Sine function designated by access value
   X := Sine_Access(Theta);

   If C3A0001_0.TC_Call_Tag /= 1 then
      Report.Failed ("Incorrect Sine_Calc_Fast result");
   end if;

   Sine_Access := C3A0001_0.Sine_Calc_Acc'Access;

   -- Invoking Sine function designated by access value
   X := Sine_Access(Theta);

   If C3A0001_0.TC_Call_Tag /= 2 then
      Report.Failed ("Incorrect Sine_Calc_Acc result");
   end if;

   Sine_Access := C3A0001_0.Sine_Calc_Table'Access;

   -- Invoking Sine function designated by access value
   X := Sine_Access(Theta);

   If C3A0001_0.TC_Call_Tag /= 3 then
      Report.Failed ("Incorrect Sine_Calc_Table result");
   end if;

   Report.Result;

end C3A0001;