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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;