-- CA11017.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 body of the parent package may depend on one of its own
-- public children.
--
-- TEST DESCRIPTION:
-- A scenario is created that demonstrates the potential of adding a
-- public child during code maintenance without distubing a large
-- subsystem. After child is added to the subsystem, a maintainer
-- decides to take advantage of the new functionality and rewrites
-- the parent's body.
--
-- Declare a string abstraction in a package which manipulates string
-- replacement. Define a parent package which provides operations for
-- a record type with discriminant. Declare a public child of this
-- package which adds functionality to the original subsystem. In the
-- parent body, call operations from the public child.
--
-- In the main program, check that operations in the parent and public
-- child perform as expected.
--
--
-- CHANGE HISTORY:
-- 06 Dec 94 SAIC ACVC 2.0
--
--!
-- Simulates application which manipulates strings.
package CA11017_0 is
type String_Rec (The_Size : positive) is private;
type Substring is new string;
-- ... Various other types used by the application.
procedure Replace (In_The_String : in out String_Rec;
At_The_Position : in positive;
With_The_String : in String_Rec);
-- ... Various other operations used by the application.
private
-- Different size for each individual record.
type String_Rec (The_Size : positive) is
record
The_Length : natural := 0;
The_Content : Substring (1 .. The_Size);
end record;
end CA11017_0;
--=================================================================--
-- Public child added during code maintenance without disturbing a
-- large system. This public child would add functionality to the
-- original system.
package CA11017_0.CA11017_1 is
Position_Error : exception;
function Equal_Length (Left : in String_Rec;
Right : in String_Rec) return boolean;
function Same_Content (Left : in String_Rec;
Right : in String_Rec) return boolean;
procedure Copy (From_The_Substring : in Substring;
To_The_String : in out String_Rec);
-- ... Various other operations used by the application.
end CA11017_0.CA11017_1;
--=================================================================--
package body CA11017_0.CA11017_1 is
function Equal_Length (Left : in String_Rec;
Right : in String_Rec) return boolean is
-- Quick comparison between the lengths of the input strings.
begin
return (Left.The_Length = Right.The_Length); -- Parent's private
-- type.
end Equal_Length;
--------------------------------------------------------------------
function Same_Content (Left : in String_Rec;
Right : in String_Rec) return boolean is
begin
for I in 1 .. Left.The_Length loop
if Left.The_Content (I) = Right.The_Content (I) then
return true;
else
return false;
end if;
end loop;
end Same_Content;
--------------------------------------------------------------------
procedure Copy (From_The_Substring : in Substring;
To_The_String : in out String_Rec) is
begin
To_The_String.The_Content -- Parent's private type.
(1 .. From_The_Substring'length) := From_The_Substring;
To_The_String.The_Length -- Parent's private type.
:= From_The_Substring'length;
end Copy;
end CA11017_0.CA11017_1;
--=================================================================--
-- After child is added to the subsystem, a maintainer decides
-- to take advantage of the new functionality and rewrites the
-- parent's body.
with CA11017_0.CA11017_1;
package body CA11017_0 is
-- Calls functions from public child for a quick comparison of the
-- input strings. If their lengths are the same, do the replacement.
procedure Replace (In_The_String : in out String_Rec;
At_The_Position : in positive;
With_The_String : in String_Rec) is
End_Position : natural := At_The_Position +
With_The_String.The_Length - 1;
begin
if not CA11017_0.CA11017_1.Equal_Length -- Public child's operation.
(With_The_String, In_The_String) then
raise CA11017_0.CA11017_1.Position_Error;
-- Public child's exception.
else
In_The_String.The_Content (At_The_Position .. End_Position) :=
With_The_String.The_Content (1 .. With_The_String.The_Length);
end if;
end Replace;
end CA11017_0;
--=================================================================--
with Report;
with CA11017_0.CA11017_1; -- Explicit with public child package,
-- implicit with parent package (CA11017_0).
procedure CA11017 is
package String_Pkg renames CA11017_0;
use String_Pkg;
begin
Report.Test ("CA11017", "Check that body of the parent package can " &
"depend on one of its own public children");
-- Both input strings have the same size. Replace the first string by the
-- second string.
Replace_Subtest:
declare
The_First_String, The_Second_String : String_Rec (16);
-- Parent's private type.
The_Position : positive := 1;
begin
CA11017_1.Copy ("This is the time",
To_The_String => The_First_String);
CA11017_1.Copy ("For all good men", The_Second_String);
Replace (The_First_String, The_Position, The_Second_String);
-- Compare results using function from public child since
-- the type is private.
if not CA11017_1.Same_Content
(The_First_String, The_Second_String) then
Report.Failed ("Incorrect results");
end if;
end Replace_Subtest;
-- During processing, the application may erroneously attempt to replace
-- strings of different size. This would result in the raising of an
-- exception.
Exception_Subtest:
declare
The_First_String : String_Rec (17);
-- Parent's private type.
The_Second_String : String_Rec (13);
-- Parent's private type.
The_Position : positive := 2;
begin
CA11017_1.Copy (" ACVC Version 2.0", The_First_String);
CA11017_1.Copy (From_The_Substring => "ACVC 9X Basic",
To_The_String => The_Second_String);
Replace (The_First_String, The_Position, The_Second_String);
Report.Failed ("Exception was not raised");
exception
when CA11017_1.Position_Error =>
Report.Comment ("Exception is raised as expected");
end Exception_Subtest;
Report.Result;
end CA11017;