gcc/ada/a-ststio.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                A D A . S T R E A M S . S T R E A M _ I O                 --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2009, 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.File_Control_Block;
  38
  39 package Ada.Streams.Stream_IO is
  40
  41    type Stream_Access is access all Root_Stream_Type'Class;
  42
  43    type File_Type is limited private;
  44
  45    type File_Mode is (In_File, Out_File, Append_File);
  46
  47    --  The following representation clause allows the use of unchecked
  48    --  conversion for rapid translation between the File_Mode type
  49    --  used in this package and System.File_IO.
  50
  51    for File_Mode use
  52      (In_File     => 0,  -- System.File_IO.File_Mode'Pos (In_File)
  53       Out_File    => 2,  -- System.File_IO.File_Mode'Pos (Out_File)
  54       Append_File => 3); -- System.File_IO.File_Mode'Pos (Append_File)
  55
  56    type Count is new Stream_Element_Offset
  57      range 0 .. Stream_Element_Offset'Last;
  58
  59    subtype Positive_Count is Count range 1 .. Count'Last;
  60    --  Index into file, in stream elements
  61
  62    ---------------------
  63    -- File Management --
  64    ---------------------
  65
  66    procedure Create
  67      (File : in out File_Type;
  68       Mode : File_Mode := Out_File;
  69       Name : String := "";
  70       Form : String := "");
  71
  72    procedure Open
  73      (File : in out File_Type;
  74       Mode : File_Mode;
  75       Name : String;
  76       Form : String := "");
  77
  78    procedure Close  (File : in out File_Type);
  79    procedure Delete (File : in out File_Type);
  80    procedure Reset  (File : in out File_Type; Mode : File_Mode);
  81    procedure Reset  (File : in out File_Type);
  82
  83    function Mode (File : File_Type) return File_Mode;
  84    function Name (File : File_Type) return String;
  85    function Form (File : File_Type) return String;
  86
  87    function Is_Open     (File : File_Type) return Boolean;
  88    function End_Of_File (File : File_Type) return Boolean;
  89
  90    function Stream (File : File_Type) return Stream_Access;
  91
  92    -----------------------------
  93    -- Input-Output Operations --
  94    -----------------------------
  95
  96    procedure Read
  97      (File : File_Type;
  98       Item : out Stream_Element_Array;
  99       Last : out Stream_Element_Offset;
 100       From : Positive_Count);
 101
 102    procedure Read
 103      (File : File_Type;
 104       Item : out Stream_Element_Array;
 105       Last : out Stream_Element_Offset);
 106
 107    procedure Write
 108      (File : File_Type;
 109       Item : Stream_Element_Array;
 110       To   : Positive_Count);
 111
 112    procedure Write
 113      (File : File_Type;
 114       Item : Stream_Element_Array);
 115
 116    ----------------------------------------
 117    -- Operations on Position within File --
 118    ----------------------------------------
 119
 120    procedure Set_Index (File : File_Type; To : Positive_Count);
 121
 122    function Index (File : File_Type) return Positive_Count;
 123    function Size  (File : File_Type) return Count;
 124
 125    procedure Set_Mode (File : in out File_Type; Mode : File_Mode);
 126
 127    --  Note: The parameter file is IN OUT in the RM, but this is clearly
 128    --  an oversight, and was intended to be IN, see AI95-00057.
 129
 130    procedure Flush (File : File_Type);
 131
 132    ----------------
 133    -- Exceptions --
 134    ----------------
 135
 136    Status_Error : exception renames IO_Exceptions.Status_Error;
 137    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 138    Name_Error   : exception renames IO_Exceptions.Name_Error;
 139    Use_Error    : exception renames IO_Exceptions.Use_Error;
 140    Device_Error : exception renames IO_Exceptions.Device_Error;
 141    End_Error    : exception renames IO_Exceptions.End_Error;
 142    Data_Error   : exception renames IO_Exceptions.Data_Error;
 143
 144 private
 145
 146    --  The following procedures have a File_Type formal of mode IN OUT because
 147    --  they may close the original file. The Close operation may raise an
 148    --  exception, but in that case we want any assignment to the formal to
 149    --  be effective anyway, so it must be passed by reference (or the caller
 150    --  will be left with a dangling pointer).
 151
 152    pragma Export_Procedure
 153      (Internal  => Close,
 154       External  => "",
 155       Mechanism => Reference);
 156    pragma Export_Procedure
 157      (Internal  => Delete,
 158       External  => "",
 159       Mechanism => Reference);
 160    pragma Export_Procedure
 161      (Internal        => Reset,
 162       External        => "",
 163       Parameter_Types => (File_Type),
 164       Mechanism       => Reference);
 165    pragma Export_Procedure
 166      (Internal        => Reset,
 167       External        => "",
 168       Parameter_Types => (File_Type, File_Mode),
 169       Mechanism       => (File => Reference));
 170    pragma Export_Procedure
 171      (Internal  => Set_Mode,
 172       External  => "",
 173       Mechanism => (File => Reference));
 174
 175    package FCB renames System.File_Control_Block;
 176
 177    -----------------------------
 178    -- Stream_IO Control Block --
 179    -----------------------------
 180
 181    type Operation is (Op_Read, Op_Write, Op_Other);
 182    --  Type used to record last operation (to optimize sequential operations)
 183
 184    type Stream_AFCB is new FCB.AFCB with record
 185       Index : Count := 1;
 186       --  Current Index value
 187
 188       File_Size : Stream_Element_Offset := -1;
 189       --  Cached value of File_Size, so that we do not keep recomputing it
 190       --  when not necessary (otherwise End_Of_File becomes gruesomely slow).
 191       --  A value of minus one means that there is no cached value.
 192
 193       Last_Op : Operation := Op_Other;
 194       --  Last operation performed on file, used to avoid unnecessary
 195       --  repositioning between successive read or write operations.
 196
 197       Update_Mode : Boolean := False;
 198       --  Set if the mode is changed from write to read or vice versa.
 199       --  Indicates that the file has been reopened in update mode.
 200
 201    end record;
 202
 203    type File_Type is access all Stream_AFCB;
 204
 205    function AFCB_Allocate (Control_Block : Stream_AFCB) return FCB.AFCB_Ptr;
 206
 207    procedure AFCB_Close (File : not null access Stream_AFCB);
 208    procedure AFCB_Free  (File : not null access Stream_AFCB);
 209
 210    procedure Read
 211      (File : in out Stream_AFCB;
 212       Item : out Ada.Streams.Stream_Element_Array;
 213       Last : out Ada.Streams.Stream_Element_Offset);
 214    --  Read operation used when Stream_IO file is treated directly as Stream
 215
 216    procedure Write
 217      (File : in out Stream_AFCB;
 218       Item : Ada.Streams.Stream_Element_Array);
 219    --  Write operation used when Stream_IO file is treated directly as Stream
 220
 221 end Ada.Streams.Stream_IO;