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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . T E X T _ I O --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2022, 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 --
-- 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 3, or (at your option) any later ver- --
-- 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- Preconditions in this unit are meant for analysis only, not for run-time
-- checking, so that the expected exceptions are raised. This is enforced by
-- setting the corresponding assertion policy to Ignore. These preconditions
-- are partial. They protect fully against Status_Error and Mode_Error,
-- partially against Layout_Error (see SPARK User's Guide for details), and
-- not against other types of errors.
pragma Assertion_Policy (Pre => Ignore);
-- 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.
with Ada.IO_Exceptions;
with Ada.Streams;
with System;
with System.File_Control_Block;
with System.WCh_Con;
package Ada.Text_IO with
SPARK_Mode,
Abstract_State => File_System,
Initializes => File_System,
Initial_Condition => Line_Length = 0 and Page_Length = 0
is
pragma Elaborate_Body;
type File_Type is limited private with
Default_Initial_Condition => (not Is_Open (File_Type));
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.
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)
type Count is range 0 .. Natural'Last;
-- The value of Count'Last must be large enough so that the assumption that
-- the Line, Column and Page counts can never exceed this value is valid.
subtype Positive_Count is Count range 1 .. Count'Last;
Unbounded : constant Count := 0;
-- Line and page length
subtype Field is Integer range 0 .. 255;
subtype Number_Base is Integer range 2 .. 16;
type Type_Set is (Lower_Case, Upper_Case);
---------------------
-- File Management --
---------------------
procedure Create
(File : in out File_Type;
Mode : File_Mode := Out_File;
Name : String := "";
Form : String := "")
with
Pre => not Is_Open (File),
Post =>
Is_Open (File)
and then Ada.Text_IO.Mode (File) = Mode
and then (if Mode /= In_File
then (Line_Length (File) = 0
and then Page_Length (File) = 0)),
Global => (In_Out => File_System);
procedure Open
(File : in out File_Type;
Mode : File_Mode;
Name : String;
Form : String := "")
with
Pre => not Is_Open (File),
Post =>
Is_Open (File)
and then Ada.Text_IO.Mode (File) = Mode
and then (if Mode /= In_File
then (Line_Length (File) = 0
and then Page_Length (File) = 0)),
Global => (In_Out => File_System);
procedure Close (File : in out File_Type) with
Pre => Is_Open (File),
Post => not Is_Open (File),
Global => (In_Out => File_System);
procedure Delete (File : in out File_Type) with
Pre => Is_Open (File),
Post => not Is_Open (File),
Global => (In_Out => File_System);
procedure Reset (File : in out File_Type; Mode : File_Mode) with
Pre => Is_Open (File),
Post =>
Is_Open (File)
and then Ada.Text_IO.Mode (File) = Mode
and then (if Mode /= In_File
then (Line_Length (File) = 0
and then Page_Length (File) = 0)),
Global => (In_Out => File_System);
procedure Reset (File : in out File_Type) with
Pre => Is_Open (File),
Post =>
Is_Open (File)
and Mode (File)'Old = Mode (File)
and (if Mode (File) /= In_File
then (Line_Length (File) = 0
and then Page_Length (File) = 0)),
Global => (In_Out => File_System);
function Mode (File : File_Type) return File_Mode with
Pre => Is_Open (File),
Global => null;
function Name (File : File_Type) return String with
Pre => Is_Open (File),
Global => null;
function Form (File : File_Type) return String with
Pre => Is_Open (File),
Global => null;
function Is_Open (File : File_Type) return Boolean with
Global => null;
------------------------------------------------------
-- Control of default input, output and error files --
------------------------------------------------------
procedure Set_Input (File : File_Type) with SPARK_Mode => Off;
procedure Set_Output (File : File_Type) with SPARK_Mode => Off;
procedure Set_Error (File : File_Type) with SPARK_Mode => Off;
function Standard_Input return File_Type with SPARK_Mode => Off;
function Standard_Output return File_Type with SPARK_Mode => Off;
function Standard_Error return File_Type with SPARK_Mode => Off;
function Current_Input return File_Type with SPARK_Mode => Off;
function Current_Output return File_Type with SPARK_Mode => Off;
function Current_Error return File_Type with SPARK_Mode => Off;
type File_Access is access constant File_Type;
function Standard_Input return File_Access with SPARK_Mode => Off;
function Standard_Output return File_Access with SPARK_Mode => Off;
function Standard_Error return File_Access with SPARK_Mode => Off;
function Current_Input return File_Access with SPARK_Mode => Off;
function Current_Output return File_Access with SPARK_Mode => Off;
function Current_Error return File_Access with SPARK_Mode => Off;
--------------------
-- Buffer control --
--------------------
-- 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.
procedure Flush (File : File_Type) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure Flush with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
--------------------------------------------
-- Specification of line and page lengths --
--------------------------------------------
procedure Set_Line_Length (File : File_Type; To : Count) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File) = To
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure Set_Line_Length (To : Count) with
Post =>
Line_Length = To
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Set_Page_Length (File : File_Type; To : Count) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Page_Length (File) = To
and Line_Length (File)'Old = Line_Length (File),
Global => (In_Out => File_System);
procedure Set_Page_Length (To : Count) with
Post =>
Page_Length = To
and Line_Length'Old = Line_Length,
Global => (In_Out => File_System);
function Line_Length (File : File_Type) return Count with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Global => (Input => File_System);
function Line_Length return Count with
Global => (Input => File_System);
function Page_Length (File : File_Type) return Count with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Global => (Input => File_System);
function Page_Length return Count with
Global => (Input => File_System);
------------------------------------
-- Column, Line, and Page Control --
------------------------------------
procedure New_Line (File : File_Type; Spacing : Positive_Count := 1) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure New_Line (Spacing : Positive_Count := 1) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Skip_Line (File : File_Type; Spacing : Positive_Count := 1) with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Skip_Line (Spacing : Positive_Count := 1) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
function End_Of_Line (File : File_Type) return Boolean with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (Input => File_System);
function End_Of_Line return Boolean with
Global => (Input => File_System);
procedure New_Page (File : File_Type) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure New_Page with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Skip_Page (File : File_Type) with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Skip_Page with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
function End_Of_Page (File : File_Type) return Boolean with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (Input => File_System);
function End_Of_Page return Boolean with
Global => (Input => File_System);
function End_Of_File (File : File_Type) return Boolean with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (Input => File_System);
function End_Of_File return Boolean with
Global => (Input => File_System);
procedure Set_Col (File : File_Type; To : Positive_Count) with
Pre =>
Is_Open (File)
and then (if Mode (File) /= In_File
then (Line_Length (File) = 0
or else To <= Line_Length (File))),
Contract_Cases =>
(Mode (File) /= In_File =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
others => True),
Global => (In_Out => File_System);
procedure Set_Col (To : Positive_Count) with
Pre => Line_Length = 0 or To <= Line_Length,
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Set_Line (File : File_Type; To : Positive_Count) with
Pre =>
Is_Open (File)
and then (if Mode (File) /= In_File
then (Page_Length (File) = 0
or else To <= Page_Length (File))),
Contract_Cases =>
(Mode (File) /= In_File =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
others => True),
Global => (In_Out => File_System);
procedure Set_Line (To : Positive_Count) with
Pre => Page_Length = 0 or To <= Page_Length,
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
function Col (File : File_Type) return Positive_Count with
Pre => Is_Open (File),
Global => (Input => File_System);
function Col return Positive_Count with
Global => (Input => File_System);
function Line (File : File_Type) return Positive_Count with
Pre => Is_Open (File),
Global => (Input => File_System);
function Line return Positive_Count with
Global => (Input => File_System);
function Page (File : File_Type) return Positive_Count with
Pre => Is_Open (File),
Global => (Input => File_System);
function Page return Positive_Count with
Global => (Input => File_System);
----------------------------
-- Character Input-Output --
----------------------------
procedure Get (File : File_Type; Item : out Character) with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Get (Item : out Character) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Put (File : File_Type; Item : Character) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure Put (Item : Character) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Look_Ahead
(File : File_Type;
Item : out Character;
End_Of_Line : out Boolean)
with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (Input => File_System);
procedure Look_Ahead
(Item : out Character;
End_Of_Line : out Boolean)
with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (Input => File_System);
procedure Get_Immediate
(File : File_Type;
Item : out Character)
with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Get_Immediate
(Item : out Character)
with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Get_Immediate
(File : File_Type;
Item : out Character;
Available : out Boolean)
with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Get_Immediate
(Item : out Character;
Available : out Boolean)
with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
-------------------------
-- String Input-Output --
-------------------------
procedure Get (File : File_Type; Item : out String) with
Pre => Is_Open (File) and then Mode (File) = In_File,
Global => (In_Out => File_System);
procedure Get (Item : out String) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Put (File : File_Type; Item : String) with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure Put (Item : String) with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
procedure Get_Line
(File : File_Type;
Item : out String;
Last : out Natural)
with
Pre => Is_Open (File) and then Mode (File) = In_File,
Post => (if Item'Length > 0 then Last in Item'First - 1 .. Item'Last
else Last = Item'First - 1),
Global => (In_Out => File_System);
procedure Get_Line
(Item : out String;
Last : out Natural)
with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length
and (if Item'Length > 0 then Last in Item'First - 1 .. Item'Last
else Last = Item'First - 1),
Global => (In_Out => File_System);
function Get_Line (File : File_Type) return String with SPARK_Mode => Off;
pragma Ada_05 (Get_Line);
function Get_Line return String with SPARK_Mode => Off;
pragma Ada_05 (Get_Line);
procedure Put_Line
(File : File_Type;
Item : String)
with
Pre => Is_Open (File) and then Mode (File) /= In_File,
Post =>
Line_Length (File)'Old = Line_Length (File)
and Page_Length (File)'Old = Page_Length (File),
Global => (In_Out => File_System);
procedure Put_Line
(Item : String)
with
Post =>
Line_Length'Old = Line_Length
and Page_Length'Old = Page_Length,
Global => (In_Out => File_System);
---------------------------------------
-- Generic packages for Input-Output --
---------------------------------------
-- The generic packages:
-- Ada.Text_IO.Integer_IO
-- 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
-- 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
-- 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.
----------------
-- Exceptions --
----------------
Status_Error : exception renames IO_Exceptions.Status_Error;
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;
Data_Error : exception renames IO_Exceptions.Data_Error;
Layout_Error : exception renames IO_Exceptions.Layout_Error;
private
pragma SPARK_Mode (Off);
-- The following procedures have a File_Type formal of mode IN OUT because
-- they may close the original file. The Close operation may raise an
-- exception, but in that case we want any assignment to the formal to
-- be effective anyway, so it must be passed by reference (or the caller
-- will be left with a dangling pointer).
pragma Export_Procedure
(Internal => Close,
External => "",
Mechanism => Reference);
pragma Export_Procedure
(Internal => Delete,
External => "",
Mechanism => Reference);
pragma Export_Procedure
(Internal => Reset,
External => "",
Parameter_Types => (File_Type),
Mechanism => Reference);
pragma Export_Procedure
(Internal => Reset,
External => "",
Parameter_Types => (File_Type, File_Mode),
Mechanism => (File => Reference));
-----------------------------------
-- 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
-- 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.
-- 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
-- or may not be a page mark separating preexisting 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
-- 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
PM : constant := Character'Pos (ASCII.FF);
-- Used as page mark, except at end of file where it is implied
--------------------------------
-- Text_IO File Control Block --
--------------------------------
Default_WCEM : System.WCh_Con.WC_Encoding_Method :=
System.WCh_Con.WCEM_UTF8;
-- This gets modified during initialization (see body) using
-- the default value established in the call to Set_Globals.
package FCB renames System.File_Control_Block;
type Text_AFCB;
type File_Type is access all Text_AFCB;
type Text_AFCB is new FCB.AFCB with record
Page : Count := 1;
Line : Count := 1;
Col : Count := 1;
Line_Length : Count := 0;
Page_Length : Count := 0;
Self : aliased File_Type;
-- Set to point to the containing Text_AFCB block. This is used to
-- implement the Current_{Error,Input,Output} functions which return
-- a File_Access, the file access value returned is a pointer to
-- the Self field of the corresponding file.
Before_LM : Boolean := False;
-- This flag is used to deal with the anomalies 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
-- 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 little odd, but it works.
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.
WC_Method : System.WCh_Con.WC_Encoding_Method := Default_WCEM;
-- Encoding method to be used for this file. Text_IO does not deal with
-- wide characters, but it does deal with upper half characters in the
-- range 16#80#-16#FF# which may need encoding, e.g. in UTF-8 mode.
Before_Upper_Half_Character : Boolean := False;
-- This flag is set to indicate that an encoded upper half character has
-- been read by Text_IO.Look_Ahead. If it is set to True, then it means
-- that the stream is logically positioned before the character but is
-- physically positioned after it. The character involved must be in
-- the range 16#80#-16#FF#, i.e. if the flag is set, then we know the
-- next character has a code greater than 16#7F#, and the value of this
-- character is saved in Saved_Upper_Half_Character.
Saved_Upper_Half_Character : Character;
-- This field is valid only if Before_Upper_Half_Character is set. It
-- contains an upper-half character read by Look_Ahead. If Look_Ahead
-- reads a character in the range 16#00# to 16#7F#, then it can use
-- ungetc to put it back, but ungetc cannot be called more than once,
-- so for characters above this range, we don't try to back up the
-- file. Instead we save the character in this field and set the flag
-- Before_Upper_Half_Character to True to indicate that we are logically
-- positioned before this character even though the stream is physically
-- positioned after it.
end record;
function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
procedure AFCB_Close (File : not null access Text_AFCB);
procedure AFCB_Free (File : not null access Text_AFCB);
procedure Read
(File : in out Text_AFCB;
Item : out Ada.Streams.Stream_Element_Array;
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;
Item : Ada.Streams.Stream_Element_Array);
-- Write operation used when Text_IO file is treated directly as Stream
------------------------
-- The Standard Files --
------------------------
Standard_In_AFCB : aliased Text_AFCB;
Standard_Out_AFCB : aliased Text_AFCB;
Standard_Err_AFCB : aliased Text_AFCB;
Standard_In : aliased File_Type := Standard_In_AFCB'Access with
Part_Of => File_System;
Standard_Out : aliased File_Type := Standard_Out_AFCB'Access with
Part_Of => File_System;
Standard_Err : aliased File_Type := Standard_Err_AFCB'Access with
Part_Of => File_System;
-- Standard files
Current_In : aliased File_Type := Standard_In with
Part_Of => File_System;
Current_Out : aliased File_Type := Standard_Out with
Part_Of => File_System;
Current_Err : aliased File_Type := Standard_Err with
Part_Of => File_System;
-- Current files
function EOF_Char return Integer;
-- Returns the system-specific character indicating the end of a text file.
-- This is exported for use by child packages such as Enumeration_Aux to
-- eliminate their needing to depend directly on Interfaces.C_Streams,
-- which might not be available in certain target environments.
procedure Initialize_Standard_Files;
-- Initializes the file control blocks for the standard files. Called from
-- the elaboration routine for this package, and from Reset_Standard_Files
-- in package Ada.Text_IO.Reset_Standard_Files.
end Ada.Text_IO;