gcc/ada/libgnat/a-direio.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                        A D A . D I R E C T _ I O                         --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2023, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  21 --                                                                          --
  22 -- As a special exception under Section 7 of GPL version 3, you are granted --
  23 -- additional permissions described in the GCC Runtime Library Exception,   --
  24 -- version 3.1, as published by the Free Software Foundation.               --
  25 --                                                                          --
  26 -- You should have received a copy of the GNU General Public License and    --
  27 -- a copy of the GCC Runtime Library Exception along with this program;     --
  28 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  29 -- <http://www.gnu.org/licenses/>.                                          --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 with Ada.IO_Exceptions;
  37 with System.Direct_IO;
  38 with Interfaces.C_Streams;
  39
  40 generic
  41    type Element_Type is private;
  42
  43 package Ada.Direct_IO is
  44
  45    pragma Compile_Time_Warning
  46      (Element_Type'Has_Access_Values,
  47       "Element_Type for Direct_IO instance has access values");
  48
  49    pragma Compile_Time_Warning
  50      (Element_Type'Has_Tagged_Values,
  51       "Element_Type for Direct_IO instance has tagged values");
  52
  53    type File_Type is limited private with Default_Initial_Condition;
  54
  55    type File_Mode is (In_File, Inout_File, Out_File);
  56
  57    --  The following representation clause allows the use of unchecked
  58    --  conversion for rapid translation between the File_Mode type
  59    --  used in this package and System.File_IO.
  60
  61    for File_Mode use
  62      (In_File    => 0,   -- System.File_IO.File_Mode'Pos (In_File)
  63       Inout_File => 1,   -- System.File_IO.File_Mode'Pos (Inout_File);
  64       Out_File   => 2);  -- System.File_IO.File_Mode'Pos (Out_File)
  65
  66    type Count is range 0 .. System.Direct_IO.Count'Last;
  67
  68    subtype Positive_Count is Count range 1 .. Count'Last;
  69
  70    ---------------------
  71    -- File Management --
  72    ---------------------
  73
  74    procedure Create
  75      (File : in out File_Type;
  76       Mode : File_Mode := Inout_File;
  77       Name : String := "";
  78       Form : String := "");
  79
  80    procedure Open
  81      (File : in out File_Type;
  82       Mode : File_Mode;
  83       Name : String;
  84       Form : String := "");
  85
  86    procedure Close  (File : in out File_Type);
  87    procedure Delete (File : in out File_Type);
  88    procedure Reset  (File : in out File_Type; Mode : File_Mode);
  89    procedure Reset  (File : in out File_Type);
  90
  91    function Mode (File : File_Type) return File_Mode;
  92    function Name (File : File_Type) return String;
  93    function Form (File : File_Type) return String;
  94
  95    function Is_Open (File : File_Type) return Boolean;
  96
  97    procedure Flush (File : File_Type);
  98
  99    ---------------------------------
 100    -- Input and Output Operations --
 101    ---------------------------------
 102
 103    procedure Read
 104      (File : File_Type;
 105       Item : out Element_Type;
 106       From : Positive_Count);
 107
 108    procedure Read
 109      (File : File_Type;
 110       Item : out Element_Type);
 111
 112    procedure Write
 113      (File : File_Type;
 114       Item : Element_Type;
 115       To   : Positive_Count);
 116
 117    procedure Write
 118      (File : File_Type;
 119       Item : Element_Type);
 120
 121    procedure Set_Index (File : File_Type; To : Positive_Count);
 122
 123    function Index (File : File_Type) return Positive_Count;
 124    function Size  (File : File_Type) return Count;
 125
 126    function End_Of_File (File : File_Type) return Boolean;
 127
 128    ----------------
 129    -- Exceptions --
 130    ----------------
 131
 132    Status_Error : exception renames IO_Exceptions.Status_Error;
 133    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 134    Name_Error   : exception renames IO_Exceptions.Name_Error;
 135    Use_Error    : exception renames IO_Exceptions.Use_Error;
 136    Device_Error : exception renames IO_Exceptions.Device_Error;
 137    End_Error    : exception renames IO_Exceptions.End_Error;
 138    Data_Error   : exception renames IO_Exceptions.Data_Error;
 139
 140 private
 141
 142    --  The following procedures have a File_Type formal of mode IN OUT because
 143    --  they may close the original file. The Close operation may raise an
 144    --  exception, but in that case we want any assignment to the formal to
 145    --  be effective anyway, so it must be passed by reference (or the caller
 146    --  will be left with a dangling pointer).
 147
 148    pragma Export_Procedure
 149      (Internal  => Close,
 150       External  => "",
 151       Mechanism => Reference);
 152    pragma Export_Procedure
 153      (Internal  => Delete,
 154       External  => "",
 155       Mechanism => Reference);
 156    pragma Export_Procedure
 157      (Internal        => Reset,
 158       External        => "",
 159       Parameter_Types => (File_Type),
 160       Mechanism       => Reference);
 161    pragma Export_Procedure
 162      (Internal        => Reset,
 163       External        => "",
 164       Parameter_Types => (File_Type, File_Mode),
 165       Mechanism       => (File => Reference));
 166
 167    type File_Type is new System.Direct_IO.File_Type;
 168
 169    Bytes : constant Interfaces.C_Streams.size_t :=
 170              Interfaces.C_Streams.size_t'Max
 171                (1, Element_Type'Max_Size_In_Storage_Elements);
 172    --  Size of an element in storage units. The Max operation here is to ensure
 173    --  that we allocate a single byte for zero-sized elements. It's a bit weird
 174    --  to instantiate Direct_IO with zero sized elements, but it is legal and
 175    --  this adjustment ensures that we don't get anomalous behavior.
 176
 177    pragma Inline (Close);
 178    pragma Inline (Create);
 179    pragma Inline (Delete);
 180    pragma Inline (End_Of_File);
 181    pragma Inline (Form);
 182    pragma Inline (Index);
 183    pragma Inline (Is_Open);
 184    pragma Inline (Mode);
 185    pragma Inline (Name);
 186    pragma Inline (Open);
 187    pragma Inline (Read);
 188    pragma Inline (Reset);
 189    pragma Inline (Set_Index);
 190    pragma Inline (Size);
 191    pragma Inline (Write);
 192
 193 end Ada.Direct_IO;