400 lines
12 KiB
Ada
400 lines
12 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- S Y S T E M . D I R E C T _ I O --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with Ada.IO_Exceptions; use Ada.IO_Exceptions;
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with Ada.Unchecked_Deallocation;
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with Interfaces.C_Streams; use Interfaces.C_Streams;
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with System; use System;
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with System.CRTL;
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with System.File_IO;
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with System.Soft_Links;
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package body System.Direct_IO is
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package FIO renames System.File_IO;
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package SSL renames System.Soft_Links;
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subtype AP is FCB.AFCB_Ptr;
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use type FCB.Shared_Status_Type;
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use type System.CRTL.int64;
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use type System.CRTL.size_t;
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-----------------------
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-- Local Subprograms --
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-----------------------
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procedure Set_Position (File : File_Type);
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-- Sets file position pointer according to value of current index
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-------------------
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-- AFCB_Allocate --
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-------------------
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function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
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pragma Unreferenced (Control_Block);
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begin
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return new Direct_AFCB;
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end AFCB_Allocate;
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----------------
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-- AFCB_Close --
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----------------
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-- No special processing required for Direct_IO close
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procedure AFCB_Close (File : not null access Direct_AFCB) is
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pragma Unreferenced (File);
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begin
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null;
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end AFCB_Close;
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---------------
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-- AFCB_Free --
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---------------
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procedure AFCB_Free (File : not null access Direct_AFCB) is
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type FCB_Ptr is access all Direct_AFCB;
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FT : FCB_Ptr := FCB_Ptr (File);
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procedure Free is new
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Ada.Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);
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begin
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Free (FT);
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end AFCB_Free;
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------------
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-- Create --
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------------
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procedure Create
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(File : in out File_Type;
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Mode : FCB.File_Mode := FCB.Inout_File;
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Name : String := "";
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Form : String := "")
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is
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Dummy_File_Control_Block : Direct_AFCB;
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pragma Warnings (Off, Dummy_File_Control_Block);
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-- Yes, we know this is never assigned a value, only the tag is used for
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-- dispatching purposes, so that's expected.
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begin
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FIO.Open (File_Ptr => AP (File),
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Dummy_FCB => Dummy_File_Control_Block,
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Mode => Mode,
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Name => Name,
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Form => Form,
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Amethod => 'D',
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Creat => True,
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Text => False);
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end Create;
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-----------------
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-- End_Of_File --
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-----------------
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function End_Of_File (File : File_Type) return Boolean is
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begin
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FIO.Check_Read_Status (AP (File));
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return File.Index > Size (File);
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end End_Of_File;
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-----------
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-- Index --
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-----------
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function Index (File : File_Type) return Positive_Count is
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begin
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FIO.Check_File_Open (AP (File));
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return File.Index;
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end Index;
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----------
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-- Open --
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----------
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procedure Open
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(File : in out File_Type;
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Mode : FCB.File_Mode;
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Name : String;
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Form : String := "")
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is
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Dummy_File_Control_Block : Direct_AFCB;
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pragma Warnings (Off, Dummy_File_Control_Block);
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-- Yes, we know this is never assigned a value, only the tag is used for
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-- dispatching purposes, so that's expected.
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begin
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FIO.Open (File_Ptr => AP (File),
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Dummy_FCB => Dummy_File_Control_Block,
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Mode => Mode,
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Name => Name,
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Form => Form,
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Amethod => 'D',
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Creat => False,
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Text => False);
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end Open;
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----------
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-- Read --
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----------
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procedure Read
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(File : File_Type;
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Item : Address;
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Size : Interfaces.C_Streams.size_t;
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From : Positive_Count)
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is
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begin
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Set_Index (File, From);
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Read (File, Item, Size);
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end Read;
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procedure Read
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(File : File_Type;
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Item : Address;
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Size : Interfaces.C_Streams.size_t)
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is
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begin
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FIO.Check_Read_Status (AP (File));
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-- If last operation was not a read, or if in file sharing mode,
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-- then reset the physical pointer of the file to match the index
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-- We lock out task access over the two operations in this case.
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if File.Last_Op /= Op_Read
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or else File.Shared_Status = FCB.Yes
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then
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if End_Of_File (File) then
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raise End_Error;
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end if;
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Locked_Processing : begin
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SSL.Lock_Task.all;
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Set_Position (File);
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FIO.Read_Buf (AP (File), Item, Size);
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SSL.Unlock_Task.all;
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exception
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when others =>
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SSL.Unlock_Task.all;
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raise;
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end Locked_Processing;
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else
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FIO.Read_Buf (AP (File), Item, Size);
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end if;
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File.Index := File.Index + 1;
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-- Set last operation to read, unless we did not read a full record
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-- (happens with the variant record case) in which case we set the
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-- last operation as other, to force the file position to be reset
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-- on the next read.
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File.Last_Op := (if File.Bytes = Size then Op_Read else Op_Other);
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end Read;
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-- The following is the required overriding for Stream.Read, which is
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-- not used, since we do not do Stream operations on Direct_IO files.
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procedure Read
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(File : in out Direct_AFCB;
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Item : out Ada.Streams.Stream_Element_Array;
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Last : out Ada.Streams.Stream_Element_Offset)
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is
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begin
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raise Program_Error;
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end Read;
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-----------
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-- Reset --
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-----------
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procedure Reset (File : in out File_Type; Mode : FCB.File_Mode) is
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pragma Warnings (Off, File);
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-- File is actually modified via Unrestricted_Access below, but
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-- GNAT will generate a warning anyway.
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--
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-- Note that we do not use pragma Unmodified here, since in -gnatc mode,
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-- GNAT will complain that File is modified for "File.Index := 1;"
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begin
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FIO.Reset (AP (File)'Unrestricted_Access, Mode);
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File.Index := 1;
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File.Last_Op := Op_Read;
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end Reset;
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procedure Reset (File : in out File_Type) is
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pragma Warnings (Off, File);
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-- See above (other Reset procedure) for explanations on this pragma
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begin
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FIO.Reset (AP (File)'Unrestricted_Access);
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File.Index := 1;
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File.Last_Op := Op_Read;
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end Reset;
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---------------
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-- Set_Index --
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---------------
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procedure Set_Index (File : File_Type; To : Positive_Count) is
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begin
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FIO.Check_File_Open (AP (File));
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File.Index := Count (To);
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File.Last_Op := Op_Other;
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end Set_Index;
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------------------
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-- Set_Position --
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------------------
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procedure Set_Position (File : File_Type) is
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R : int;
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begin
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R :=
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fseek64
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(File.Stream, int64 (File.Bytes) * int64 (File.Index - 1), SEEK_SET);
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if R /= 0 then
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raise Use_Error;
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end if;
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end Set_Position;
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----------
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-- Size --
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----------
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function Size (File : File_Type) return Count is
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Pos : int64;
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begin
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FIO.Check_File_Open (AP (File));
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File.Last_Op := Op_Other;
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if fseek64 (File.Stream, 0, SEEK_END) /= 0 then
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raise Device_Error;
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end if;
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Pos := ftell64 (File.Stream);
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if Pos = -1 then
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raise Use_Error;
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end if;
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return Count (Pos / int64 (File.Bytes));
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end Size;
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-----------
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-- Write --
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-----------
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procedure Write
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(File : File_Type;
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Item : Address;
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Size : Interfaces.C_Streams.size_t;
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Zeroes : System.Storage_Elements.Storage_Array)
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is
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procedure Do_Write;
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-- Do the actual write
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--------------
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-- Do_Write --
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--------------
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procedure Do_Write is
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begin
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FIO.Write_Buf (AP (File), Item, Size);
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-- If we did not write the whole record (happens with the variant
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-- record case), then fill out the rest of the record with zeroes.
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-- This is cleaner in any case, and is required for the last
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-- record, since otherwise the length of the file is wrong.
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if File.Bytes > Size then
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FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
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end if;
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end Do_Write;
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-- Start of processing for Write
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begin
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FIO.Check_Write_Status (AP (File));
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-- If last operation was not a write, or if in file sharing mode,
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-- then reset the physical pointer of the file to match the index
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-- We lock out task access over the two operations in this case.
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if File.Last_Op /= Op_Write
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or else File.Shared_Status = FCB.Yes
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then
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Locked_Processing : begin
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SSL.Lock_Task.all;
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Set_Position (File);
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Do_Write;
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SSL.Unlock_Task.all;
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exception
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when others =>
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SSL.Unlock_Task.all;
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raise;
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end Locked_Processing;
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else
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Do_Write;
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end if;
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File.Index := File.Index + 1;
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-- Set last operation to write, unless we did not read a full record
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-- (happens with the variant record case) in which case we set the
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-- last operation as other, to force the file position to be reset
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-- on the next write.
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File.Last_Op := (if File.Bytes = Size then Op_Write else Op_Other);
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end Write;
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-- The following is the required overriding for Stream.Write, which is
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-- not used, since we do not do Stream operations on Direct_IO files.
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procedure Write
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(File : in out Direct_AFCB;
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Item : Ada.Streams.Stream_Element_Array)
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is
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begin
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raise Program_Error;
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end Write;
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end System.Direct_IO;
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