306 lines
9.7 KiB
Ada
306 lines
9.7 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- A D A . S E Q U E N T I A L _ I O --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2013, 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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-- This is the generic template for Sequential_IO, i.e. the code that gets
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-- duplicated. We absolutely minimize this code by either calling routines
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-- in System.File_IO (for common file functions), or in System.Sequential_IO
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-- (for specialized Sequential_IO functions)
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with Ada.Unchecked_Conversion;
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with System;
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with System.Byte_Swapping;
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with System.CRTL;
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with System.File_Control_Block;
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with System.File_IO;
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with System.Storage_Elements;
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with Interfaces.C_Streams; use Interfaces.C_Streams;
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package body Ada.Sequential_IO is
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package FIO renames System.File_IO;
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package FCB renames System.File_Control_Block;
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package SIO renames System.Sequential_IO;
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package SSE renames System.Storage_Elements;
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SU : constant := System.Storage_Unit;
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subtype AP is FCB.AFCB_Ptr;
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subtype FP is SIO.File_Type;
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function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
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function To_SIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
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use type System.Bit_Order;
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use type System.CRTL.size_t;
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procedure Byte_Swap (Siz : in out size_t);
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-- Byte swap Siz
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---------------
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-- Byte_Swap --
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---------------
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procedure Byte_Swap (Siz : in out size_t) is
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use System.Byte_Swapping;
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begin
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case Siz'Size is
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when 32 => Siz := size_t (Bswap_32 (U32 (Siz)));
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when 64 => Siz := size_t (Bswap_64 (U64 (Siz)));
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when others => raise Program_Error;
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end case;
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end Byte_Swap;
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-----------
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-- Close --
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-----------
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procedure Close (File : in out File_Type) is
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begin
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FIO.Close (AP (File)'Unrestricted_Access);
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end Close;
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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 : File_Mode := Out_File;
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Name : String := "";
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Form : String := "")
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is
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begin
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SIO.Create (FP (File), To_FCB (Mode), Name, Form);
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end Create;
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------------
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-- Delete --
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------------
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procedure Delete (File : in out File_Type) is
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begin
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FIO.Delete (AP (File)'Unrestricted_Access);
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end Delete;
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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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return FIO.End_Of_File (AP (File));
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end End_Of_File;
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----------
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-- Form --
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----------
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function Form (File : File_Type) return String is
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begin
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return FIO.Form (AP (File));
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end Form;
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-------------
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-- Is_Open --
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-------------
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function Is_Open (File : File_Type) return Boolean is
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begin
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return FIO.Is_Open (AP (File));
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end Is_Open;
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----------
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-- Mode --
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----------
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function Mode (File : File_Type) return File_Mode is
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begin
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return To_SIO (FIO.Mode (AP (File)));
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end Mode;
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----------
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-- Name --
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----------
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function Name (File : File_Type) return String is
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begin
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return FIO.Name (AP (File));
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end Name;
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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 : File_Mode;
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Name : String;
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Form : String := "")
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is
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begin
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SIO.Open (FP (File), To_FCB (Mode), Name, Form);
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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 (File : File_Type; Item : out Element_Type) is
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Siz : constant size_t := (Item'Size + SU - 1) / SU;
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Rsiz : size_t;
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begin
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FIO.Check_Read_Status (AP (File));
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-- For non-definite type or type with discriminants, read size and
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-- raise Program_Error if it is larger than the size of the item.
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if not Element_Type'Definite
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or else Element_Type'Has_Discriminants
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then
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FIO.Read_Buf
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(AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
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-- If item read has non-default scalar storage order, then the size
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-- will have been written with that same order, so byte swap it.
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if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
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Byte_Swap (Rsiz);
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end if;
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-- For a type with discriminants, we have to read into a temporary
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-- buffer if Item is constrained, to check that the discriminants
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-- are correct.
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if Element_Type'Has_Discriminants and then Item'Constrained then
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declare
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RsizS : constant SSE.Storage_Offset :=
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SSE.Storage_Offset (Rsiz - 1);
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type SA is new SSE.Storage_Array (0 .. RsizS);
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for SA'Alignment use Standard'Maximum_Alignment;
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-- We will perform an unchecked conversion of a pointer-to-SA
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-- into pointer-to-Element_Type. We need to ensure that the
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-- source is always at least as strictly aligned as the target.
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type SAP is access all SA;
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type ItemP is access all Element_Type;
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pragma Warnings (Off);
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-- We have to turn warnings off for function To_ItemP,
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-- because it gets analyzed for all types, including ones
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-- which can't possibly come this way, and for which the
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-- size of the access types differs.
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function To_ItemP is new Ada.Unchecked_Conversion (SAP, ItemP);
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pragma Warnings (On);
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Buffer : aliased SA;
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pragma Unsuppress (Discriminant_Check);
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begin
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FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
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Item := To_ItemP (Buffer'Access).all;
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return;
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end;
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end if;
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-- In the case of a non-definite type, make sure the length is OK.
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-- We can't do this in the variant record case, because the size is
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-- based on the current discriminant, so may be apparently wrong.
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if not Element_Type'Has_Discriminants and then Rsiz > Siz then
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raise Program_Error;
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end if;
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FIO.Read_Buf (AP (File), Item'Address, Rsiz);
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-- For definite type without discriminants, use actual size of item
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else
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FIO.Read_Buf (AP (File), Item'Address, Siz);
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end if;
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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 : File_Mode) is
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begin
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FIO.Reset (AP (File)'Unrestricted_Access, To_FCB (Mode));
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end Reset;
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procedure Reset (File : in out File_Type) is
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begin
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FIO.Reset (AP (File)'Unrestricted_Access);
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end Reset;
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-----------
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-- Write --
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-----------
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procedure Write (File : File_Type; Item : Element_Type) is
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Siz : constant size_t := (Item'Size + SU - 1) / SU;
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-- Size to be written, in native representation
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Swapped_Siz : size_t := Siz;
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-- Same, possibly byte swapped to account for Element_Type endianness
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begin
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FIO.Check_Write_Status (AP (File));
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-- For non-definite types or types with discriminants, write the size
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if not Element_Type'Definite
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or else Element_Type'Has_Discriminants
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then
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-- If item written has non-default scalar storage order, then the
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-- size is written with that same order, so byte swap it.
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if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
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Byte_Swap (Swapped_Siz);
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end if;
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FIO.Write_Buf
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(AP (File), Swapped_Siz'Address, size_t'Size / System.Storage_Unit);
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end if;
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FIO.Write_Buf (AP (File), Item'Address, Siz);
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end Write;
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end Ada.Sequential_IO;
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