File : a-textio.ads
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
5 -- A D A . T E X T _ I O --
-- --
-- S p e c --
-- --
-- $Revision: 1.51 $
10 -- --
-- Copyright (C) 1992-2000 Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
15 -- apply solely to the contents of the part following the private keyword. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
20 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
25 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
30 -- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
35 -- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
40 -- Note: the generic subpackages of Text_IO (Integer_IO, Float_IO, Fixed_IO,
-- Modular_IO, Decimal_IO and Enumeration_IO) appear as private children in
-- GNAT. These children are with'ed automatically if they are referenced, so
-- this rearrangement is invisible to user programs, but has the advantage
-- that only the needed parts of Text_IO are processed and loaded.
45
with Ada.IO_Exceptions;
with Ada.Streams;
with System;
with System.File_Control_Block;
50
package Ada.Text_IO is
pragma Elaborate_Body (Text_IO);
type File_Type is limited private;
55 type File_Mode is (In_File, Out_File, Append_File);
-- The following representation clause allows the use of unchecked
-- conversion for rapid translation between the File_Mode type
-- used in this package and System.File_IO.
60
for File_Mode use
(In_File => 0, -- System.FIle_IO.File_Mode'Pos (In_File)
Out_File => 2, -- System.File_IO.File_Mode'Pos (Out_File)
Append_File => 3); -- System.File_IO.File_Mode'Pos (Append_File)
65
type Count is range 0 .. Natural'Last;
-- The value of Count'Last must be large enough so that the assumption
-- enough so that the assumption that the Line, Column and Page
-- counts can never exceed this value is a valid assumption.
70
subtype Positive_Count is Count range 1 .. Count'Last;
Unbounded : constant Count := 0;
-- Line and page length
75
subtype Field is Integer range 0 .. 255;
-- Note: if for any reason, there is a need to increase this value,
-- then it will be necessary to change the corresponding value in
-- System.Img_Real in file s-imgrea.adb.
80
subtype Number_Base is Integer range 2 .. 16;
type Type_Set is (Lower_Case, Upper_Case);
85 ---------------------
-- File Management --
---------------------
procedure Create
90 (File : in out File_Type;
Mode : in File_Mode := Out_File;
Name : in String := "";
Form : in String := "");
95 procedure Open
(File : in out File_Type;
Mode : in File_Mode;
Name : in String;
Form : in String := "");
100
procedure Close (File : in out File_Type);
procedure Delete (File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : in File_Mode);
procedure Reset (File : in out File_Type);
105
function Mode (File : in File_Type) return File_Mode;
function Name (File : in File_Type) return String;
function Form (File : in File_Type) return String;
110 function Is_Open (File : in File_Type) return Boolean;
------------------------------------------------------
-- Control of default input, output and error files --
------------------------------------------------------
115
procedure Set_Input (File : in File_Type);
procedure Set_Output (File : in File_Type);
procedure Set_Error (File : in File_Type);
120 function Standard_Input return File_Type;
function Standard_Output return File_Type;
function Standard_Error return File_Type;
function Current_Input return File_Type;
125 function Current_Output return File_Type;
function Current_Error return File_Type;
type File_Access is access constant File_Type;
130 function Standard_Input return File_Access;
function Standard_Output return File_Access;
function Standard_Error return File_Access;
function Current_Input return File_Access;
135 function Current_Output return File_Access;
function Current_Error return File_Access;
--------------------
-- Buffer control --
140 --------------------
-- Note: The parameter file is IN OUT in the RM, but this is clearly
-- an oversight, and was intended to be IN, see AI95-00057.
145 procedure Flush (File : in File_Type);
procedure Flush;
--------------------------------------------
-- Specification of line and page lengths --
150 --------------------------------------------
procedure Set_Line_Length (File : in File_Type; To : in Count);
procedure Set_Line_Length (To : in Count);
155 procedure Set_Page_Length (File : in File_Type; To : in Count);
procedure Set_Page_Length (To : in Count);
function Line_Length (File : in File_Type) return Count;
function Line_Length return Count;
160
function Page_Length (File : in File_Type) return Count;
function Page_Length return Count;
------------------------------------
165 -- Column, Line, and Page Control --
------------------------------------
procedure New_Line (File : in File_Type; Spacing : in Positive_Count := 1);
procedure New_Line (Spacing : in Positive_Count := 1);
170
procedure Skip_Line (File : in File_Type; Spacing : in Positive_Count := 1);
procedure Skip_Line (Spacing : in Positive_Count := 1);
function End_Of_Line (File : in File_Type) return Boolean;
175 function End_Of_Line return Boolean;
procedure New_Page (File : in File_Type);
procedure New_Page;
180 procedure Skip_Page (File : in File_Type);
procedure Skip_Page;
function End_Of_Page (File : in File_Type) return Boolean;
function End_Of_Page return Boolean;
185
function End_Of_File (File : in File_Type) return Boolean;
function End_Of_File return Boolean;
procedure Set_Col (File : in File_Type; To : in Positive_Count);
190 procedure Set_Col (To : in Positive_Count);
procedure Set_Line (File : in File_Type; To : in Positive_Count);
procedure Set_Line (To : in Positive_Count);
195 function Col (File : in File_Type) return Positive_Count;
function Col return Positive_Count;
function Line (File : in File_Type) return Positive_Count;
function Line return Positive_Count;
200
function Page (File : in File_Type) return Positive_Count;
function Page return Positive_Count;
----------------------------
205 -- Character Input-Output --
----------------------------
procedure Get (File : in File_Type; Item : out Character);
procedure Get (Item : out Character);
210 procedure Put (File : in File_Type; Item : in Character);
procedure Put (Item : in Character);
procedure Look_Ahead
(File : in File_Type;
215 Item : out Character;
End_Of_Line : out Boolean);
procedure Look_Ahead
(Item : out Character;
220 End_Of_Line : out Boolean);
procedure Get_Immediate
(File : in File_Type;
Item : out Character);
225
procedure Get_Immediate
(Item : out Character);
procedure Get_Immediate
230 (File : in File_Type;
Item : out Character;
Available : out Boolean);
procedure Get_Immediate
235 (Item : out Character;
Available : out Boolean);
-------------------------
-- String Input-Output --
240 -------------------------
procedure Get (File : in File_Type; Item : out String);
procedure Get (Item : out String);
procedure Put (File : in File_Type; Item : in String);
245 procedure Put (Item : in String);
procedure Get_Line
(File : in File_Type;
Item : out String;
250 Last : out Natural);
procedure Get_Line
(Item : out String;
Last : out Natural);
255
procedure Put_Line
(File : in File_Type;
Item : in String);
260 procedure Put_Line
(Item : in String);
---------------------------------------
-- Generic packages for Input-Output --
265 ---------------------------------------
-- The generic packages:
-- Ada.Text_IO.Integer_IO
270 -- Ada.Text_IO.Modular_IO
-- Ada.Text_IO.Float_IO
-- Ada.Text_IO.Fixed_IO
-- Ada.Text_IO.Decimal_IO
-- Ada.Text_IO.Enumeration_IO
275
-- are implemented as separate child packages in GNAT, so the
-- spec and body of these packages are to be found in separate
-- child units. This implementation detail is hidden from the
-- Ada programmer by special circuitry in the compiler that
280 -- treats these child packages as though they were nested in
-- Text_IO. The advantage of this special processing is that
-- the subsidiary routines needed if these generics are used
-- are not loaded when they are not used.
285 ----------------
-- Exceptions --
----------------
Status_Error : exception renames IO_Exceptions.Status_Error;
290 Mode_Error : exception renames IO_Exceptions.Mode_Error;
Name_Error : exception renames IO_Exceptions.Name_Error;
Use_Error : exception renames IO_Exceptions.Use_Error;
Device_Error : exception renames IO_Exceptions.Device_Error;
End_Error : exception renames IO_Exceptions.End_Error;
295 Data_Error : exception renames IO_Exceptions.Data_Error;
Layout_Error : exception renames IO_Exceptions.Layout_Error;
private
-----------------------------------
300 -- Handling of Format Characters --
-----------------------------------
-- Line marks are represented by the single character ASCII.LF (16#0A#).
-- In DOS and similar systems, underlying file translation takes care
305 -- of translating this to and from the standard CR/LF sequences used in
-- these operating systems to mark the end of a line. On output there is
-- always a line mark at the end of the last line, but on input, this
-- line mark can be omitted, and is implied by the end of file.
310 -- Page marks are represented by the single character ASCII.FF (16#0C#),
-- The page mark at the end of the file may be omitted, and is normally
-- omitted on output unless an explicit New_Page call is made before
-- closing the file. No page mark is added when a file is appended to,
-- so, in accordance with the permission in (RM A.10.2(4)), there may
315 -- or may not be a page mark separating preexising text in the file
-- from the new text to be written.
-- A file mark is marked by the physical end of file. In DOS translation
-- mode on input, an EOF character (SUB = 16#1A#) gets translated to the
320 -- physical end of file, so in effect this character is recognized as
-- marking the end of file in DOS and similar systems.
LM : constant := Character'Pos (ASCII.LF);
-- Used as line mark
325
PM : constant := Character'Pos (ASCII.FF);
-- Used as page mark, except at end of file where it is implied
--------------------------------
330 -- Text_IO File Control Block --
--------------------------------
package FCB renames System.File_Control_Block;
335 type Text_AFCB;
type File_Type is access all Text_AFCB;
type Text_AFCB is new FCB.AFCB with record
Page : Count := 1;
340 Line : Count := 1;
Col : Count := 1;
Line_Length : Count := 0;
Page_Length : Count := 0;
345 Self : aliased File_Type;
-- Set to point to the containing Text_AFCB block. This is used to
-- implement the Current_{Error,Input,Ouput} functions which return
-- a File_Access, the file access value returned is a pointer to
-- the Self field of the corresponding file.
350
Before_LM : Boolean := False;
-- This flag is used to deal with the anomolies introduced by the
-- peculiar definition of End_Of_File and End_Of_Page in Ada. These
-- functions require looking ahead more than one character. Since
355 -- there is no convenient way of backing up more than one character,
-- what we do is to leave ourselves positioned past the LM, but set
-- this flag, so that we know that from an Ada point of view we are
-- in front of the LM, not after it. A bit of a kludge, but it works!
360 Before_LM_PM : Boolean := False;
-- This flag similarly handles the case of being physically positioned
-- after a LM-PM sequence when logically we are before the LM-PM. This
-- flag can only be set if Before_LM is also set.
365 end record;
function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
procedure AFCB_Close (File : access Text_AFCB);
370 procedure AFCB_Free (File : access Text_AFCB);
procedure Read
(File : in out Text_AFCB;
Item : out Ada.Streams.Stream_Element_Array;
375 Last : out Ada.Streams.Stream_Element_Offset);
-- Read operation used when Text_IO file is treated directly as Stream
procedure Write
(File : in out Text_AFCB;
380 Item : in Ada.Streams.Stream_Element_Array);
-- Write operation used when Text_IO file is treated directly as Stream
------------------------
-- The Standard Files --
385 ------------------------
Null_Str : aliased constant String := "";
-- Used as name and form of standard files
390 Standard_Err_AFCB : aliased Text_AFCB;
Standard_In_AFCB : aliased Text_AFCB;
Standard_Out_AFCB : aliased Text_AFCB;
Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
395 Standard_In : aliased File_Type := Standard_In_AFCB'Access;
Standard_Out : aliased File_Type := Standard_Out_AFCB'Access;
-- Standard files
Current_In : aliased File_Type := Standard_In;
400 Current_Out : aliased File_Type := Standard_Out;
Current_Err : aliased File_Type := Standard_Err;
-- Current files
-----------------------
405 -- Local Subprograms --
-----------------------
-- These subprograms are in the private part of the spec so that they can
-- be shared by the routines in the body of Ada.Text_IO.Wide_Text_IO.
410
-- Note: we use Integer in these declarations instead of the more accurate
-- Interfaces.C_Streams.int, because we do not want to drag in the spec of
-- this interfaces package with the spec of Ada.Text_IO, and we know that
-- in fact these types are identical
415
function Getc (File : File_Type) return Integer;
-- Gets next character from file, which has already been checked for
-- being in read status, and returns the character read if no error
-- occurs. The result is EOF if the end of file was read.
420
function Nextc (File : File_Type) return Integer;
-- Returns next character from file without skipping past it (i.e. it
-- is a combination of Getc followed by an Ungetc).
425 procedure Putc (ch : Integer; File : File_Type);
-- Outputs the given character to the file, which has already been
-- checked for being in output status. Device_Error is raised if the
-- character cannot be written.
430 procedure Terminate_Line (File : File_Type);
-- If the file is in Write_File or Append_File mode, and the current
-- line is not terminated, then a line terminator is written using
-- New_Line. Note that there is no Terminate_Page routine, because
-- the page mark at the end of the file is implied if necessary.
435
procedure Ungetc (ch : Integer; File : File_Type);
-- Pushes back character into stream, using ungetc. The caller has
-- checked that the file is in read status. Device_Error is raised
-- if the character cannot be pushed back. An attempt to push back
440 -- and end of file character (EOF) is ignored.
end Ada.Text_IO;