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314 | ------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . S E Q U E N T I A L _ I O --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2020, 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 is the generic template for Sequential_IO, i.e. the code that gets
-- duplicated. We absolutely minimize this code by either calling routines
-- in System.File_IO (for common file functions), or in System.Sequential_IO
-- (for specialized Sequential_IO functions)
with Ada.Unchecked_Conversion;
with System;
with System.Byte_Swapping;
with System.CRTL;
with System.File_Control_Block;
with System.File_IO;
with System.Storage_Elements;
with Interfaces.C_Streams; use Interfaces.C_Streams;
package body Ada.Sequential_IO is
package FIO renames System.File_IO;
package FCB renames System.File_Control_Block;
package SIO renames System.Sequential_IO;
package SSE renames System.Storage_Elements;
SU : constant := System.Storage_Unit;
subtype AP is FCB.AFCB_Ptr;
subtype FP is SIO.File_Type;
function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
function To_SIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
use type System.Bit_Order;
use type System.CRTL.size_t;
procedure Byte_Swap (Siz : in out size_t);
-- Byte swap Siz
---------------
-- Byte_Swap --
---------------
procedure Byte_Swap (Siz : in out size_t) is
use System.Byte_Swapping;
begin
case size_t'Size is
when 32 => Siz := size_t (Bswap_32 (U32 (Siz)));
when 64 => Siz := size_t (Bswap_64 (U64 (Siz)));
when others => raise Program_Error;
end case;
end Byte_Swap;
-----------
-- Close --
-----------
procedure Close (File : in out File_Type) is
begin
FIO.Close (AP (File)'Unrestricted_Access);
end Close;
------------
-- Create --
------------
procedure Create
(File : in out File_Type;
Mode : File_Mode := Out_File;
Name : String := "";
Form : String := "")
is
begin
SIO.Create (FP (File), To_FCB (Mode), Name, Form);
end Create;
------------
-- Delete --
------------
procedure Delete (File : in out File_Type) is
begin
FIO.Delete (AP (File)'Unrestricted_Access);
end Delete;
-----------------
-- End_Of_File --
-----------------
function End_Of_File (File : File_Type) return Boolean is
begin
return FIO.End_Of_File (AP (File));
end End_Of_File;
-----------
-- Flush --
-----------
procedure Flush (File : File_Type) is
begin
FIO.Flush (AP (File));
end Flush;
----------
-- Form --
----------
function Form (File : File_Type) return String is
begin
return FIO.Form (AP (File));
end Form;
-------------
-- Is_Open --
-------------
function Is_Open (File : File_Type) return Boolean is
begin
return FIO.Is_Open (AP (File));
end Is_Open;
----------
-- Mode --
----------
function Mode (File : File_Type) return File_Mode is
begin
return To_SIO (FIO.Mode (AP (File)));
end Mode;
----------
-- Name --
----------
function Name (File : File_Type) return String is
begin
return FIO.Name (AP (File));
end Name;
----------
-- Open --
----------
procedure Open
(File : in out File_Type;
Mode : File_Mode;
Name : String;
Form : String := "")
is
begin
SIO.Open (FP (File), To_FCB (Mode), Name, Form);
end Open;
----------
-- Read --
----------
procedure Read (File : File_Type; Item : out Element_Type) is
Siz : constant size_t := (Item'Size + SU - 1) / SU;
Rsiz : size_t;
begin
FIO.Check_Read_Status (AP (File));
-- For non-definite type or type with discriminants, read size and
-- raise Program_Error if it is larger than the size of the item.
if not Element_Type'Definite
or else Element_Type'Has_Discriminants
then
FIO.Read_Buf
(AP (File), Rsiz'Address, size_t'Size / System.Storage_Unit);
-- If item read has non-default scalar storage order, then the size
-- will have been written with that same order, so byte swap it.
if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
Byte_Swap (Rsiz);
end if;
-- For a type with discriminants, we have to read into a temporary
-- buffer if Item is constrained, to check that the discriminants
-- are correct.
if Element_Type'Has_Discriminants and then Item'Constrained then
declare
RsizS : constant SSE.Storage_Offset :=
SSE.Storage_Offset (Rsiz - 1);
type SA is new SSE.Storage_Array (0 .. RsizS);
for SA'Alignment use Standard'Maximum_Alignment;
-- We will perform an unchecked conversion of a pointer-to-SA
-- into pointer-to-Element_Type. We need to ensure that the
-- source is always at least as strictly aligned as the target.
type SAP is access all SA;
type ItemP is access all Element_Type;
pragma Warnings (Off);
-- We have to turn warnings off for function To_ItemP,
-- because it gets analyzed for all types, including ones
-- which can't possibly come this way, and for which the
-- size of the access types differs.
function To_ItemP is new Ada.Unchecked_Conversion (SAP, ItemP);
pragma Warnings (On);
Buffer : aliased SA;
pragma Unsuppress (Discriminant_Check);
begin
FIO.Read_Buf (AP (File), Buffer'Address, Rsiz);
Item := To_ItemP (Buffer'Access).all;
return;
end;
end if;
-- In the case of a non-definite type, make sure the length is OK.
-- We can't do this in the variant record case, because the size is
-- based on the current discriminant, so may be apparently wrong.
if not Element_Type'Has_Discriminants and then Rsiz > Siz then
raise Program_Error;
end if;
FIO.Read_Buf (AP (File), Item'Address, Rsiz);
-- For definite type without discriminants, use actual size of item
else
FIO.Read_Buf (AP (File), Item'Address, Siz);
end if;
end Read;
-----------
-- Reset --
-----------
procedure Reset (File : in out File_Type; Mode : File_Mode) is
begin
FIO.Reset (AP (File)'Unrestricted_Access, To_FCB (Mode));
end Reset;
procedure Reset (File : in out File_Type) is
begin
FIO.Reset (AP (File)'Unrestricted_Access);
end Reset;
-----------
-- Write --
-----------
procedure Write (File : File_Type; Item : Element_Type) is
Siz : constant size_t := (Item'Size + SU - 1) / SU;
-- Size to be written, in native representation
Swapped_Siz : size_t := Siz;
-- Same, possibly byte swapped to account for Element_Type endianness
begin
FIO.Check_Write_Status (AP (File));
-- For non-definite types or types with discriminants, write the size
if not Element_Type'Definite
or else Element_Type'Has_Discriminants
then
-- If item written has non-default scalar storage order, then the
-- size is written with that same order, so byte swap it.
if Element_Type'Scalar_Storage_Order /= System.Default_Bit_Order then
Byte_Swap (Swapped_Siz);
end if;
FIO.Write_Buf
(AP (File), Swapped_Siz'Address, size_t'Size / System.Storage_Unit);
end if;
FIO.Write_Buf (AP (File), Item'Address, Siz);
end Write;
end Ada.Sequential_IO;
|