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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                     S Y S T E M . D I R E C T _ I O                      --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --   Copyright (C) 1992,1993,1994,1995,1996 Free Software Foundation, Inc.  --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This package contains the declaration of the control block used for
  36 --  Direct_IO. This must be declared at the outer library level. It also
  37 --  contains code that is shared between instances of Direct_IO.
  38
  39 with Interfaces.C_Streams;
  40 with Ada.Streams;
  41 with System.File_Control_Block;
  42 with System.Storage_Elements;
  43
  44 package System.Direct_IO is
  45
  46    package FCB renames System.File_Control_Block;
  47
  48    type Operation is (Op_Read, Op_Write, Op_Other);
  49    --  Type used to record last operation (to optimize sequential operations)
  50
  51    subtype Count is Interfaces.C_Streams.long;
  52    --  The Count type in each instantiation is derived from this type
  53
  54    subtype Positive_Count is Count range 1 .. Count'Last;
  55
  56    type Direct_AFCB is new FCB.AFCB with record
  57       Index : Count := 1;
  58       --  Current Index value
  59
  60       Bytes : Interfaces.C_Streams.size_t;
  61       --  Length of item in bytes (set from inside generic template)
  62
  63       Last_Op : Operation := Op_Other;
  64       --  Last operation performed on file, used to avoid unnecessary
  65       --  repositioning between successive read or write operations.
  66    end record;
  67
  68    function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr;
  69
  70    procedure AFCB_Close (File : access Direct_AFCB);
  71    procedure AFCB_Free  (File : access Direct_AFCB);
  72
  73    procedure Read
  74      (File : in out Direct_AFCB;
  75       Item : out Ada.Streams.Stream_Element_Array;
  76       Last : out Ada.Streams.Stream_Element_Offset);
  77    --  Required overriding of Read, not actually used for Direct_IO
  78
  79    procedure Write
  80      (File : in out Direct_AFCB;
  81       Item : in Ada.Streams.Stream_Element_Array);
  82    --  Required overriding of Write, not actually used for Direct_IO
  83
  84    type File_Type is access all Direct_AFCB;
  85    --  File_Type in individual instantiations is derived from this type
  86
  87    procedure Create
  88      (File : in out File_Type;
  89       Mode : in FCB.File_Mode := FCB.Inout_File;
  90       Name : in String := "";
  91       Form : in String := "");
  92
  93    function End_Of_File (File : in File_Type) return Boolean;
  94
  95    function Index (File : in File_Type) return Positive_Count;
  96
  97    procedure Open
  98      (File : in out File_Type;
  99       Mode : in FCB.File_Mode;
 100       Name : in String;
 101       Form : in String := "");
 102
 103    procedure Read
 104      (File : in File_Type;
 105       Item : System.Address;
 106       Size : in Interfaces.C_Streams.size_t;
 107       From : in Positive_Count);
 108
 109    procedure Read
 110      (File : in File_Type;
 111       Item : System.Address;
 112       Size : in Interfaces.C_Streams.size_t);
 113
 114    procedure Reset (File : in out File_Type; Mode : in FCB.File_Mode);
 115
 116    procedure Reset (File : in out File_Type);
 117
 118    procedure Set_Index (File : in File_Type; To : in Positive_Count);
 119
 120    function Size (File : in File_Type) return Count;
 121
 122    procedure Write
 123      (File   : in File_Type;
 124       Item   : System.Address;
 125       Size   : in Interfaces.C_Streams.size_t;
 126       Zeroes : System.Storage_Elements.Storage_Array);
 127    --  Note: Zeroes is the buffer of zeroes used to fill out partial records
 128
 129 end System.Direct_IO;