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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . D I R E C T _ I O --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2022, Free Software Foundation, Inc. --
-- --
-- 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. --
-- --
------------------------------------------------------------------------------
-- This package contains the declaration of the control block used for
-- Direct_IO. This must be declared at the outer library level. It also
-- contains code that is shared between instances of Direct_IO.
with Interfaces.C_Streams;
with Ada.Streams;
with System.File_Control_Block;
with System.Storage_Elements;
package System.Direct_IO is
package FCB renames System.File_Control_Block;
type Operation is (Op_Read, Op_Write, Op_Other);
-- Type used to record last operation (to optimize sequential operations)
subtype Count is Interfaces.C_Streams.int64;
-- The Count type in each instantiation is derived from this type
subtype Positive_Count is Count range 1 .. Count'Last;
type Direct_AFCB is new FCB.AFCB with record
Index : Count := 1;
-- Current Index value
Bytes : Interfaces.C_Streams.size_t;
-- Length of item in bytes (set from inside generic template)
Last_Op : Operation := Op_Other;
-- Last operation performed on file, used to avoid unnecessary
-- repositioning between successive read or write operations.
end record;
function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr;
procedure AFCB_Close (File : not null access Direct_AFCB);
procedure AFCB_Free (File : not null access Direct_AFCB);
procedure Read
(File : in out Direct_AFCB;
Item : out Ada.Streams.Stream_Element_Array;
Last : out Ada.Streams.Stream_Element_Offset);
-- Required overriding of Read, not actually used for Direct_IO
procedure Write
(File : in out Direct_AFCB;
Item : Ada.Streams.Stream_Element_Array);
-- Required overriding of Write, not actually used for Direct_IO
type File_Type is access all Direct_AFCB;
-- File_Type in individual instantiations is derived from this type
procedure Create
(File : in out File_Type;
Mode : FCB.File_Mode := FCB.Inout_File;
Name : String := "";
Form : String := "");
function End_Of_File (File : File_Type) return Boolean;
function Index (File : File_Type) return Positive_Count;
procedure Open
(File : in out File_Type;
Mode : FCB.File_Mode;
Name : String;
Form : String := "");
procedure Read
(File : File_Type;
Item : System.Address;
Size : Interfaces.C_Streams.size_t;
From : Positive_Count);
procedure Read
(File : File_Type;
Item : System.Address;
Size : Interfaces.C_Streams.size_t);
procedure Reset (File : in out File_Type; Mode : FCB.File_Mode);
procedure Reset (File : in out File_Type);
procedure Set_Index (File : File_Type; To : Positive_Count);
function Size (File : File_Type) return Count;
procedure Write
(File : File_Type;
Item : System.Address;
Size : Interfaces.C_Streams.size_t;
Zeroes : System.Storage_Elements.Storage_Array);
-- Note: Zeroes is the buffer of zeroes used to fill out partial records
-- 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 => Reset,
External => "",
Parameter_Types => (File_Type),
Mechanism => Reference);
pragma Export_Procedure
(Internal => Reset,
External => "",
Parameter_Types => (File_Type, FCB.File_Mode),
Mechanism => (File => Reference));
end System.Direct_IO;
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