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224 | ------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . S T R E A M S . S T R E A M _ I O --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2020, 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. --
-- --
------------------------------------------------------------------------------
with Ada.IO_Exceptions;
with System.File_Control_Block;
package Ada.Streams.Stream_IO is
pragma Preelaborate;
type Stream_Access is access all Root_Stream_Type'Class;
type File_Type is limited private with Default_Initial_Condition;
pragma Preelaborable_Initialization (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 new Stream_Element_Offset
range 0 .. Stream_Element_Offset'Last;
subtype Positive_Count is Count range 1 .. Count'Last;
-- Index into file, in stream elements
---------------------
-- File Management --
---------------------
procedure Create
(File : in out File_Type;
Mode : File_Mode := Out_File;
Name : String := "";
Form : String := "");
procedure Open
(File : in out File_Type;
Mode : File_Mode;
Name : String;
Form : String := "");
procedure Close (File : in out File_Type);
procedure Delete (File : in out File_Type);
procedure Reset (File : in out File_Type; Mode : File_Mode);
procedure Reset (File : in out File_Type);
function Mode (File : File_Type) return File_Mode;
function Name (File : File_Type) return String;
function Form (File : File_Type) return String;
function Is_Open (File : File_Type) return Boolean;
function End_Of_File (File : File_Type) return Boolean;
function Stream (File : File_Type) return Stream_Access;
-----------------------------
-- Input-Output Operations --
-----------------------------
procedure Read
(File : File_Type;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset;
From : Positive_Count);
procedure Read
(File : File_Type;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset);
procedure Write
(File : File_Type;
Item : Stream_Element_Array;
To : Positive_Count);
procedure Write
(File : File_Type;
Item : Stream_Element_Array);
----------------------------------------
-- Operations on Position within File --
----------------------------------------
procedure Set_Index (File : File_Type; To : Positive_Count);
function Index (File : File_Type) return Positive_Count;
function Size (File : File_Type) return Count;
procedure Set_Mode (File : in out File_Type; Mode : File_Mode);
-- 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);
----------------
-- 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;
private
-- 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));
pragma Export_Procedure
(Internal => Set_Mode,
External => "",
Mechanism => (File => Reference));
package FCB renames System.File_Control_Block;
-----------------------------
-- Stream_IO Control Block --
-----------------------------
type Operation is (Op_Read, Op_Write, Op_Other);
-- Type used to record last operation (to optimize sequential operations)
type Stream_AFCB is new FCB.AFCB with record
Index : Count := 1;
-- Current Index value
File_Size : Stream_Element_Offset := -1;
-- Cached value of File_Size, so that we do not keep recomputing it
-- when not necessary (otherwise End_Of_File becomes gruesomely slow).
-- A value of minus one means that there is no cached value.
Last_Op : Operation := Op_Other;
-- Last operation performed on file, used to avoid unnecessary
-- repositioning between successive read or write operations.
Update_Mode : Boolean := False;
-- Set if the mode is changed from write to read or vice versa.
-- Indicates that the file has been reopened in update mode.
end record;
type File_Type is access all Stream_AFCB;
overriding function AFCB_Allocate
(Control_Block : Stream_AFCB) return FCB.AFCB_Ptr;
overriding procedure AFCB_Close (File : not null access Stream_AFCB);
overriding procedure AFCB_Free (File : not null access Stream_AFCB);
overriding procedure Read
(File : in out Stream_AFCB;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
-- Read operation used when Stream_IO file is treated directly as Stream
overriding procedure Write
(File : in out Stream_AFCB;
Item : Ada.Streams.Stream_Element_Array);
-- Write operation used when Stream_IO file is treated directly as Stream
end Ada.Streams.Stream_IO;
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