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 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- This specification is derived from the Ada Reference Manual for use with --
  13 -- GNAT. The copyright notice above, and the license provisions that follow --
  14 -- apply solely to the  contents of the part following the private keyword. --
  15 --                                                                          --
  16 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  17 -- terms of the  GNU General Public License as published  by the Free Soft- --
  18 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  19 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  20 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  21 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  22 -- for  more details.  You should have  received  a copy of the GNU General --
  23 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  24 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  25 -- MA 02111-1307, USA.                                                      --
  26 --                                                                          --
  27 -- As a special exception,  if other files  instantiate  generics from this --
  28 -- unit, or you link  this unit with other files  to produce an executable, --
  29 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  30 -- covered  by the  GNU  General  Public  License.  This exception does not --
  31 -- however invalidate  any other reasons why  the executable file  might be --
  32 -- covered by the  GNU Public License.                                      --
  33 --                                                                          --
  34 -- GNAT was originally developed  by the GNAT team at  New York University. --
  35 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  36 --                                                                          --
  37 ------------------------------------------------------------------------------
  38
  39 with Ada.IO_Exceptions;
  40 with System.File_Control_Block;
  41
  42 package Ada.Streams.Stream_IO is
  43
  44    type Stream_Access is access all Root_Stream_Type'Class;
  45
  46    type File_Type is limited private;
  47
  48    type File_Mode is (In_File, Out_File, Append_File);
  49
  50    --  The following representation clause allows the use of unchecked
  51    --  conversion for rapid translation between the File_Mode type
  52    --  used in this package and System.File_IO.
  53
  54    for File_Mode use
  55      (In_File     => 0,  -- System.FIle_IO.File_Mode'Pos (In_File)
  56       Out_File    => 2,  -- System.File_IO.File_Mode'Pos (Out_File)
  57       Append_File => 3); -- System.File_IO.File_Mode'Pos (Append_File)
  58
  59    type Count is new Stream_Element_Offset
  60      range 0 .. Stream_Element_Offset'Last;
  61
  62    subtype Positive_Count is Count range 1 .. Count'Last;
  63    --  Index into file, in stream elements
  64
  65    ---------------------
  66    -- File Management --
  67    ---------------------
  68
  69    procedure Create
  70      (File : in out File_Type;
  71       Mode : in File_Mode := Out_File;
  72       Name : in String := "";
  73       Form : in String := "");
  74
  75    procedure Open
  76      (File : in out File_Type;
  77       Mode : in File_Mode;
  78       Name : in String;
  79       Form : in String := "");
  80
  81    procedure Close  (File : in out File_Type);
  82    procedure Delete (File : in out File_Type);
  83    procedure Reset  (File : in out File_Type; Mode : in File_Mode);
  84    procedure Reset  (File : in out File_Type);
  85
  86    function Mode (File : in File_Type) return File_Mode;
  87    function Name (File : in File_Type) return String;
  88    function Form (File : in File_Type) return String;
  89
  90    function Is_Open     (File : in File_Type) return Boolean;
  91    function End_Of_File (File : in File_Type) return Boolean;
  92
  93    function Stream (File : in File_Type) return Stream_Access;
  94
  95    -----------------------------
  96    -- Input-Output Operations --
  97    -----------------------------
  98
  99    procedure Read
 100      (File : in  File_Type;
 101       Item : out Stream_Element_Array;
 102       Last : out Stream_Element_Offset;
 103       From : in  Positive_Count);
 104
 105    procedure Read
 106      (File : in  File_Type;
 107       Item : out Stream_Element_Array;
 108       Last : out Stream_Element_Offset);
 109
 110    procedure Write
 111      (File : in File_Type;
 112       Item : in Stream_Element_Array;
 113       To   : in Positive_Count);
 114
 115    procedure Write
 116      (File : in File_Type;
 117       Item : in Stream_Element_Array);
 118
 119    ----------------------------------------
 120    -- Operations on Position within File --
 121    ----------------------------------------
 122
 123    procedure Set_Index (File : in File_Type; To : in Positive_Count);
 124
 125    function Index (File : in File_Type) return Positive_Count;
 126    function Size  (File : in File_Type) return Count;
 127
 128    procedure Set_Mode (File : in out File_Type; Mode : in File_Mode);
 129
 130    --  Note: The parameter file is IN OUT in the RM, but this is clearly
 131    --  an oversight, and was intended to be IN, see AI95-00057.
 132
 133    procedure Flush (File : File_Type);
 134
 135    ----------------
 136    -- Exceptions --
 137    ----------------
 138
 139    Status_Error : exception renames IO_Exceptions.Status_Error;
 140    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 141    Name_Error   : exception renames IO_Exceptions.Name_Error;
 142    Use_Error    : exception renames IO_Exceptions.Use_Error;
 143    Device_Error : exception renames IO_Exceptions.Device_Error;
 144    End_Error    : exception renames IO_Exceptions.End_Error;
 145    Data_Error   : exception renames IO_Exceptions.Data_Error;
 146
 147 private
 148    package FCB renames System.File_Control_Block;
 149
 150    -----------------------------
 151    -- Stream_IO Control Block --
 152    -----------------------------
 153
 154    type Operation is (Op_Read, Op_Write, Op_Other);
 155    --  Type used to record last operation (to optimize sequential operations)
 156
 157    type Stream_AFCB is new FCB.AFCB with record
 158       Index : Count := 1;
 159       --  Current Index value
 160
 161       File_Size : Stream_Element_Offset := -1;
 162       --  Cached value of File_Size, so that we do not keep recomputing it
 163       --  when not necessary (otherwise End_Of_File becomes gruesomely slow).
 164       --  A value of minus one means that there is no cached value.
 165
 166       Last_Op : Operation := Op_Other;
 167       --  Last operation performed on file, used to avoid unnecessary
 168       --  repositioning between successive read or write operations.
 169
 170       Update_Mode : Boolean := False;
 171       --  Set if the mode is changed from write to read or vice versa.
 172       --  Indicates that the file has been reopened in update mode.
 173
 174    end record;
 175
 176    type File_Type is access all Stream_AFCB;
 177
 178    function AFCB_Allocate (Control_Block : Stream_AFCB) return FCB.AFCB_Ptr;
 179
 180    procedure AFCB_Close (File : access Stream_AFCB);
 181    procedure AFCB_Free  (File : access Stream_AFCB);
 182
 183    procedure Read
 184      (File : in out Stream_AFCB;
 185       Item : out Ada.Streams.Stream_Element_Array;
 186       Last : out Ada.Streams.Stream_Element_Offset);
 187    --  Read operation used when Stream_IO file is treated directly as Stream
 188
 189    procedure Write
 190      (File : in out Stream_AFCB;
 191       Item : in Ada.Streams.Stream_Element_Array);
 192    --  Write operation used when Stream_IO file is treated directly as Stream
 193
 194 end Ada.Streams.Stream_IO;