-- CXAA013.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 exception Mode_Error is raised when an attempt is made
--      to skip a line or page using the predefined Skip_Line and Skip_Page
--      procedures on a text file with mode Append_File.
--      
-- TEST DESCRIPTION:
--      A scenario is created that demonstrates the potential for the 
--      incorrect usage of predefined text processing subprograms, which 
--      results in the raising of a Mode_Error exception.
--      A count is kept to ensure that each anticipated exception is in fact
--      raised and handled properly.
--      
-- APPLICABILITY CRITERIA: 
--      This test is applicable only to implementations that support text
--      files.
--
--       
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--      28 Feb 97   PWB.CTA Allowed for non-support of some IO operations
--!

with Ada.Text_IO;
with Report;

procedure CXAA013 is
   use Ada;
   Text_File     : Text_IO.File_Type;
   Text_Filename : constant String := 
                              Report.Legal_File_Name ( Nam => "CXAA013" );
   Incomplete : exception;

begin

         Report.Test ("CXAA013", "Check that the exception Mode_Error is " &
                                 "raised when an attempt is made to skip " &
                                 "a line or page using the predefined "    &
                                 "Skip_Line and Skip_Page procedures on "  &
                                 "a text file with mode Append_File");

         Test_for_Text_IO_Support:
         begin

-- An application creates a text file with mode Append_File.
-- Use_Error will be raised if Text_IO operations or external files are not
-- supported.

            Text_IO.Create (Text_File, Text_IO.Append_File, Text_Filename);

   exception

       when Text_IO.Use_Error | Text_IO.Name_Error =>
          Report.Not_Applicable
             ( "Files not supported - Create as Append_File for Text_IO" );
          raise Incomplete;

   end Test_for_Text_IO_Support;

-- The application writes some amount of data to the file.

   Text_IO.Put_Line (Text_File, "Data entered into the file");

   Operational_Test_Block:
   declare
      TC_Number_Of_Forced_Mode_Errors : constant Natural := 2;
      TC_Mode_Errors : Natural := 0;
   begin

      Test_for_Skip_Line:
      declare
         TC_Spacing : constant Text_IO.Count := 3;
      begin

-- During the course of its processing, the application may attempt to 
-- invoke the Skip_Line procedure on a file that is currently in Append_File 
-- mode (instead of the anticipated In_File mode).  This results in the 
-- raising of Mode_Error.

         Text_IO.Skip_Line (Text_File, TC_Spacing);
         Report.Failed ("Exception not raised by Skip_Line");

-- An exception handler present within the application handles the exception
-- and processing can continue.

      exception
         when Text_IO.Mode_Error => 
            TC_Mode_Errors := TC_Mode_Errors + 1;
         when others => 
            Report.Failed("Exception in Skip_Line processing");
      end Test_for_Skip_Line;

      Test_for_Skip_Page:
      begin

-- Again, during the course of its processing, the application incorrectly
-- assumes that the file mode is In_File, this time attempting to call the 
-- Skip_Page procedure for the file (that is currently in Append_File mode).

         Text_IO.Skip_Page (Text_File);
         Report.Failed ("Exception not raised by Skip_Page");

-- Once again, an exception handler present within the application handles 
-- the exception and processing continues.

      exception
         when Text_IO.Mode_Error => 
            TC_Mode_Errors := TC_Mode_Errors + 1;
         when others => 
            Report.Failed("Exception in Skip_Page processing");
      end Test_for_Skip_Page;

      if (TC_Mode_Errors /= TC_Number_Of_Forced_Mode_Errors) then
         Report.Failed ("Incorrect number of exceptions handled");
      end if;

   end Operational_Test_Block;

   Deletion:
   begin
      -- Delete the external file.
      if Text_IO.Is_Open (Text_File) then
         Text_IO.Delete (Text_File);     
      else
         Text_IO.Open (Text_File, Text_IO.In_File, Text_Filename);
         Text_IO.Delete (Text_File);     
      end if;
   exception
      when others =>
         Report.Failed
            ( "Delete not properly implemented for Text_IO" );
   end Deletion;

   Report.Result;

exception
   when Incomplete =>
      Report.Result;
   when others     =>
      Report.Failed ( "Unexpected exception" );
      Report.Result;

end CXAA013;