-- CXAA016.A
--
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--     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 
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--     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 type File_Access is available in Ada.Text_IO, and that
--      objects of this type designate File_Type objects.
--      Check that function Set_Error will set the current default error file.
--      Check that versions of Ada.Text_IO functions Standard_Input,
--      Standard_Output, Standard_Error return File_Access values designating
--      the standard system input, output, and error files.
--      Check that versions of Ada.Text_IO functions Current_Input,
--      Current_Output, Current_Error return File_Access values designating
--      the current system input, output, and error files.
--      
-- TEST DESCRIPTION:
--      This test tests the use of File_Access objects in referring 
--      to File_Type objects, as well as several new functions that return 
--      File_Access objects as results.
--      Four user-defined files are created.  These files will be set to 
--      function as current system input, output, and error files.
--      Data will be read from and written to these files during the
--      time at which they function as the current system files.  
--      An array of File_Access objects will be defined.  It will be 
--      initialized using functions that return File_Access objects 
--      referencing the Standard and Current Input, Output, and Error files.
--      This "saves" the initial system environment, which will be modified
--      to use the user-defined files as the current default Input, Output,
--      and Error files.  At the end of the test, the data in this array 
--      will be used to restore the initial system environment.
--      
-- APPLICABILITY CRITERIA: 
--      This test is applicable to implementations capable of supporting
--      external Text_IO files.
--
--       
-- CHANGE HISTORY:
--      25 May 95   SAIC    Initial prerelease version.
--      22 Apr 96   SAIC    Incorporated reviewer comments for ACVC 2.1.
--      26 Feb 97   PWB.CTA Allowed for non-support of some IO operations.
--      18 Jan 99   RLB     Repaired to allow Not_Applicable systems to
--                          fail delete.
--!

with Ada.Text_IO;
package CXAA016_0 is
   New_Input_File,
   New_Output_File,
   New_Error_File_1,
   New_Error_File_2 : aliased Ada.Text_IO.File_Type;
end CXAA016_0;


with Report;
with Ada.Exceptions;
with Ada.Text_IO; use Ada.Text_IO;
with CXAA016_0;   use CXAA016_0;

procedure CXAA016 is
   
   Non_Applicable_System : exception;
   No_Reset              : exception;
   Not_Applicable_System : Boolean := False;

   procedure Delete_File ( A_File : in out Ada.Text_IO.File_Type;
                           ID_Num : in     Integer ) is
   begin
      if not Ada.Text_IO.Is_Open ( A_File ) then
         Ada.Text_IO.Open ( A_File, 
                            Ada.Text_IO.In_File, 
                            Report.Legal_File_Name ( ID_Num ) );
      end if;
      Ada.Text_IO.Delete ( A_File );
   exception
      when Ada.Text_IO.Name_Error =>
         if Not_Applicable_System then
            null; -- File probably wasn't created.
         else
            Report.Failed ( "Can't open file for Text_IO" );
         end if;
      when Ada.Text_IO.Use_Error =>
         if Not_Applicable_System then
            null; -- File probably wasn't created.
         else
            Report.Failed ( "Delete not properly implemented for Text_IO" );
         end if;
      when others                =>
         Report.Failed ( "Unexpected exception in Delete_File" );
   end Delete_File;

begin

   Report.Test ("CXAA016", "Check that the type File_Access is available " &
                           "in Ada.Text_IO, and that objects of this "     &
                           "type designate File_Type objects");
   Test_Block:
   declare

      use Ada.Exceptions;

      type System_File_Array_Type is 
        array (Integer range <>) of File_Access;        

      -- Fill the following array with the File_Access results of six
      -- functions.

      Initial_Environment : System_File_Array_Type(1..6) := 
                              ( Standard_Input,
                                Standard_Output,
                                Standard_Error,
                                Current_Input,    
                                Current_Output,
                                Current_Error );

      New_Input_Ptr    : File_Access := New_Input_File'Access;
      New_Output_Ptr   : File_Access := New_Output_File'Access;
      New_Error_Ptr    : File_Access := New_Error_File_1'Access;

      Line   : String(1..80);
      Length : Natural := 0;

      Line_1 : constant String := "This is the first line in the Output file";
      Line_2 : constant String := "This is the next line in the Output file";
      Line_3 : constant String := "This is the first line in Error file 1";
      Line_4 : constant String := "This is the next line in Error file 1";
      Line_5 : constant String := "This is the first line in Error file 2";
      Line_6 : constant String := "This is the next line in Error file 2";


      procedure New_File (The_File : in out File_Type;
                          Mode     : in     File_Mode;
                          Next     : in     Integer) is
      begin
         Create (The_File, Mode, Report.Legal_File_Name(Next));
      exception
         -- The following two exceptions may be raised if a system is not
         -- capable of supporting external Text_IO files.  The handler will
         -- raise a user-defined exception which will result in a 
         -- Not_Applicable result for the test.
         when Use_Error | Name_Error => raise Non_Applicable_System;
      end New_File;


      procedure Check_Initial_Environment (Env : System_File_Array_Type) is
      begin
        -- Check that the system has defined the following sources/
        -- destinations for input/output/error, and that the six functions
        -- returning File_Access values are available.
        if not (Env(1) = Standard_Input  and
                Env(2) = Standard_Output and
                Env(3) = Standard_Error  and    
                Env(4) = Current_Input   and
                Env(5) = Current_Output  and
                Env(6) = Current_Error) 
        then
           Report.Failed("At the start of the test, the Standard and " &
                         "Current File_Access values associated with " &
                         "system Input, Output, and Error files do "   &
                         "not correspond");
        end if;
      end Check_Initial_Environment;


      procedure Load_Input_File (Input_Ptr : in File_Access) is
      begin
         -- Load data into the file that will function as the user-defined
         -- system input file.
         Put_Line(Input_Ptr.all, Line_1);
         Put_Line(Input_Ptr.all, Line_2);
         Put_Line(Input_Ptr.all, Line_3);
         Put_Line(Input_Ptr.all, Line_4);
         Put_Line(Input_Ptr.all, Line_5);
         Put_Line(Input_Ptr.all, Line_6);
      end Load_Input_File;


      procedure Restore_Initial_Environment 
                  (Initial_Env : System_File_Array_Type) is 
      begin
         -- Restore the Current Input, Output, and Error files to their
         -- original states.

         Set_Input (Initial_Env(4).all);
         Set_Output(Initial_Env(5).all);
         Set_Error (Initial_Env(6).all);

         -- At this point, the user-defined files that were functioning as
         -- the Current Input, Output, and Error files have been replaced in
         -- that capacity by the state of the original environment.

         declare

            -- Capture the state of the current environment.

            Current_Env : System_File_Array_Type (1..6) := 
                            (Standard_Input, Standard_Output, Standard_Error,
                             Current_Input,  Current_Output,  Current_Error);
         begin

            -- Compare the current environment with that of the saved  
            -- initial environment.

            if Current_Env /= Initial_Env then
               Report.Failed("Restored file environment was not the same " &
                             "as the initial file environment");
            end if;
         end;
      end Restore_Initial_Environment;


      procedure Verify_Files (O_File, E_File_1, E_File_2 : in File_Type) is
         Str_1, Str_2, Str_3, Str_4, Str_5, Str_6 : String (1..80);
         Len_1, Len_2, Len_3, Len_4, Len_5, Len_6 : Natural;
      begin
         
         -- Get the lines that are contained in all the files, and verify
         -- them against the expected results.

         Get_Line(O_File, Str_1, Len_1);  -- The user defined output file 
         Get_Line(O_File, Str_2, Len_2);  -- should contain two lines of data.
       
         if Str_1(1..Len_1) /= Line_1 or
            Str_2(1..Len_2) /= Line_2
         then
            Report.Failed("Incorrect results from Current_Output file");
         end if;

         Get_Line(E_File_1, Str_3, Len_3);  -- The first error file received 
         Get_Line(E_File_1, Str_4, Len_4);  -- two lines of data originally,
         Get_Line(E_File_1, Str_5, Len_5);  -- then had two additional lines
         Get_Line(E_File_1, Str_6, Len_6);  -- appended from the second error
                                            -- file.
         if Str_3(1..Len_3) /= Line_3 or
            Str_4(1..Len_4) /= Line_4 or
            Str_5(1..Len_5) /= Line_5 or
            Str_6(1..Len_6) /= Line_6 
         then
            Report.Failed("Incorrect results from first Error file");
         end if;

         Get_Line(E_File_2, Str_5, Len_5);  -- The second error file
         Get_Line(E_File_2, Str_6, Len_6);  -- received two lines of data.

         if Str_5(1..Len_5) /= Line_5 or
            Str_6(1..Len_6) /= Line_6 
         then
            Report.Failed("Incorrect results from second Error file");
         end if;

      end Verify_Files;


   begin

      Check_Initial_Environment (Initial_Environment);

      -- Create user-defined text files that will be set to serve as current
      -- system input, output, and error files.

      New_File (New_Input_File,   Out_File, 1); -- Will be reset prior to use.
      New_File (New_Output_File,  Out_File, 2);
      New_File (New_Error_File_1, Out_File, 3);
      New_File (New_Error_File_2, Out_File, 4);

      -- Enter several lines of text into the new input file.  This file will
      -- be reset to mode In_File to function as the current system input file.
      -- Note: File_Access value used as parameter to this procedure.
      
      Load_Input_File (New_Input_Ptr);

      -- Reset the New_Input_File to mode In_File, to allow it to act as the
      -- current system input file.

      Reset1:
      begin
         Reset (New_Input_File, In_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to In_File not supported for Text_IO - 1" );
            raise No_Reset;
      end Reset1;

      -- Establish new files that will function as the current system Input,
      -- Output, and Error files.
      
      Set_Input (New_Input_File);
      Set_Output(New_Output_Ptr.all);
      Set_Error (New_Error_Ptr.all);      

      -- Perform various file processing tasks, exercising specific new
      -- Text_IO functionality.
      --
      -- Read two lines from Current_Input and write them to Current_Output.

      for i in 1..2 loop
         Get_Line(Current_Input,  Line, Length);
         Put_Line(Current_Output, Line(1..Length));
      end loop;

      -- Read two lines from Current_Input and write them to Current_Error.

      for i in 1..2 loop
         Get_Line(Current_Input, Line, Length);
         Put_Line(Current_Error, Line(1..Length));
      end loop;

      -- Reset the Current system error file.

      Set_Error (New_Error_File_2);      

      -- Read two lines from Current_Input and write them to Current_Error.

      for i in 1..2 loop
         Get_Line(Current_Input, Line, Length);
         Put_Line(Current_Error, Line(1..Length));
      end loop;

      -- At this point in the processing, the new Output file, and each of
      -- the two Error files, contain two lines of data.
      -- Note that New_Error_File_1 has been replaced by New_Error_File_2
      -- as the current system error file, allowing New_Error_File_1 to be
      -- reset (Mode_Error raised otherwise).
      --
      -- Reset the first Error file to Append_File mode, and then set it to 
      -- function as the current system error file.

      Reset2:
      begin
         Reset (New_Error_File_1, Append_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to Append_File not supported for Text_IO - 2" );
            raise No_Reset;
      end Reset2;

      Set_Error (New_Error_File_1);

      -- Reset the second Error file to In_File mode, then set it to become
      -- the current system input file.

      Reset3:
      begin
         Reset (New_Error_File_2, In_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to In_File not supported for Text_IO - 3" );
            raise No_Reset;
      end Reset3;

      New_Error_Ptr := New_Error_File_2'Access; 
      Set_Input (New_Error_Ptr.all);

      -- Append all of the text lines (2) in the new current system input
      -- file onto the current system error file.

      while not End_Of_File(Current_Input) loop
         Get_Line(Current_Input, Line, Length);
         Put_Line(Current_Error, Line(1..Length));
      end loop;

      -- Restore the original system file environment, based upon the values
      -- stored at the start of this test.
      -- Check that the original environment has been restored.

      Restore_Initial_Environment (Initial_Environment);

      -- Reset all three files to In_File_Mode prior to verification.
      -- Note: If these three files had still been the designated Current
      --       Input, Output, or Error files for the system, a Reset 
      --       operation at this point would raise Mode_Error.
      --       However, at this point, the environment has been restored to
      --       its original state, and these user-defined files are no longer
      --       designated as current system files, allowing a Reset.

      Reset4:
      begin
         Reset(New_Error_File_1, In_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to In_File not supported for Text_IO - 4" );
            raise No_Reset;
      end Reset4;

      Reset5:
      begin
         Reset(New_Error_File_2, In_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to In_File not supported for Text_IO - 5" );
            raise No_Reset;
      end Reset5;

      Reset6:
      begin
         Reset(New_Output_File,  In_File);
      exception
         when Ada.Text_IO.Use_Error =>
            Report.Not_Applicable
               ( "Reset to In_File not supported for Text_IO - 6" );
            raise No_Reset;
      end Reset6;

      -- Check that all the files contain the appropriate data.

      Verify_Files (New_Output_File, New_Error_File_1, New_Error_File_2);

   exception
      when No_Reset =>
         null;
      when Non_Applicable_System =>
         Report.Not_Applicable("System not capable of supporting external " &
                               "text files -- Name_Error/Use_Error raised " &
                               "during text file creation");
         Not_Applicable_System := True;
      when The_Error : others => 
         Report.Failed ("The following exception was raised in the " &
                        "Test_Block: " & Exception_Name(The_Error));
   end Test_Block;

   Delete_Block:
   begin
      Delete_File ( New_Input_File, 1 );
      Delete_File ( New_Output_File, 2 );
      Delete_File ( New_Error_File_1, 3 );
      Delete_File ( New_Error_File_2, 4 );
   end Delete_Block;

   Report.Result;

end CXAA016;