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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME 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 --          Copyright (C) 1992-2014, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This package contains the declaration of the control block used for
  33 --  Direct_IO. This must be declared at the outer library level. It also
  34 --  contains code that is shared between instances of Direct_IO.
  35
  36 with Interfaces.C_Streams;
  37 with Ada.Streams;
  38 with System.File_Control_Block;
  39 with System.Storage_Elements;
  40
  41 package System.Direct_IO is
  42
  43    package FCB renames System.File_Control_Block;
  44
  45    type Operation is (Op_Read, Op_Write, Op_Other);
  46    --  Type used to record last operation (to optimize sequential operations)
  47
  48    subtype Count is Interfaces.C_Streams.int64;
  49    --  The Count type in each instantiation is derived from this type
  50
  51    subtype Positive_Count is Count range 1 .. Count'Last;
  52
  53    type Direct_AFCB is new FCB.AFCB with record
  54       Index : Count := 1;
  55       --  Current Index value
  56
  57       Bytes : Interfaces.C_Streams.size_t;
  58       --  Length of item in bytes (set from inside generic template)
  59
  60       Last_Op : Operation := Op_Other;
  61       --  Last operation performed on file, used to avoid unnecessary
  62       --  repositioning between successive read or write operations.
  63    end record;
  64
  65    function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr;
  66
  67    procedure AFCB_Close (File : not null access Direct_AFCB);
  68    procedure AFCB_Free  (File : not null access Direct_AFCB);
  69
  70    procedure Read
  71      (File : in out Direct_AFCB;
  72       Item : out Ada.Streams.Stream_Element_Array;
  73       Last : out Ada.Streams.Stream_Element_Offset);
  74    --  Required overriding of Read, not actually used for Direct_IO
  75
  76    procedure Write
  77      (File : in out Direct_AFCB;
  78       Item : Ada.Streams.Stream_Element_Array);
  79    --  Required overriding of Write, not actually used for Direct_IO
  80
  81    type File_Type is access all Direct_AFCB;
  82    --  File_Type in individual instantiations is derived from this type
  83
  84    procedure Create
  85      (File : in out File_Type;
  86       Mode : FCB.File_Mode := FCB.Inout_File;
  87       Name : String := "";
  88       Form : String := "");
  89
  90    function End_Of_File (File : File_Type) return Boolean;
  91
  92    function Index (File : File_Type) return Positive_Count;
  93
  94    procedure Open
  95      (File : in out File_Type;
  96       Mode : FCB.File_Mode;
  97       Name : String;
  98       Form : String := "");
  99
 100    procedure Read
 101      (File : File_Type;
 102       Item : System.Address;
 103       Size : Interfaces.C_Streams.size_t;
 104       From : Positive_Count);
 105
 106    procedure Read
 107      (File : File_Type;
 108       Item : System.Address;
 109       Size : Interfaces.C_Streams.size_t);
 110
 111    procedure Reset (File : in out File_Type; Mode : FCB.File_Mode);
 112    procedure Reset (File : in out File_Type);
 113
 114    procedure Set_Index (File : File_Type; To : Positive_Count);
 115
 116    function Size (File : File_Type) return Count;
 117
 118    procedure Write
 119      (File   : File_Type;
 120       Item   : System.Address;
 121       Size   : Interfaces.C_Streams.size_t;
 122       Zeroes : System.Storage_Elements.Storage_Array);
 123    --  Note: Zeroes is the buffer of zeroes used to fill out partial records
 124
 125    --  The following procedures have a File_Type formal of mode IN OUT because
 126    --  they may close the original file. The Close operation may raise an
 127    --  exception, but in that case we want any assignment to the formal to
 128    --  be effective anyway, so it must be passed by reference (or the caller
 129    --  will be left with a dangling pointer).
 130
 131    pragma Export_Procedure
 132      (Internal        => Reset,
 133       External        => "",
 134       Parameter_Types => (File_Type),
 135       Mechanism       => Reference);
 136    pragma Export_Procedure
 137      (Internal        => Reset,
 138       External        => "",
 139       Parameter_Types => (File_Type, FCB.File_Mode),
 140       Mechanism       => (File => Reference));
 141
 142 end System.Direct_IO;