1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . D I R E C T _ I O --
9 -- $Revision: 1.10 $ --
11 -- Copyright (C) 1992,1993,1994,1995,1996 Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 -- This package contains the declaration of the control block used for
37 -- Direct_IO. This must be declared at the outer library level. It also
38 -- contains code that is shared between instances of Direct_IO.
40 with Interfaces.C_Streams;
42 with System.File_Control_Block;
43 with System.Storage_Elements;
45 package System.Direct_IO is
47 package FCB renames System.File_Control_Block;
49 type Operation is (Op_Read, Op_Write, Op_Other);
50 -- Type used to record last operation (to optimize sequential operations)
52 subtype Count is Interfaces.C_Streams.long;
53 -- The Count type in each instantiation is derived from this type
55 subtype Positive_Count is Count range 1 .. Count'Last;
57 type Direct_AFCB is new FCB.AFCB with record
59 -- Current Index value
61 Bytes : Interfaces.C_Streams.size_t;
62 -- Length of item in bytes (set from inside generic template)
64 Last_Op : Operation := Op_Other;
65 -- Last operation performed on file, used to avoid unnecessary
66 -- repositioning between successive read or write operations.
69 function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr;
71 procedure AFCB_Close (File : access Direct_AFCB);
72 procedure AFCB_Free (File : access Direct_AFCB);
75 (File : in out Direct_AFCB;
76 Item : out Ada.Streams.Stream_Element_Array;
77 Last : out Ada.Streams.Stream_Element_Offset);
78 -- Required overriding of Read, not actually used for Direct_IO
81 (File : in out Direct_AFCB;
82 Item : in Ada.Streams.Stream_Element_Array);
83 -- Required overriding of Write, not actually used for Direct_IO
85 type File_Type is access all Direct_AFCB;
86 -- File_Type in individual instantiations is derived from this type
89 (File : in out File_Type;
90 Mode : in FCB.File_Mode := FCB.Inout_File;
91 Name : in String := "";
92 Form : in String := "");
94 function End_Of_File (File : in File_Type) return Boolean;
96 function Index (File : in File_Type) return Positive_Count;
99 (File : in out File_Type;
100 Mode : in FCB.File_Mode;
102 Form : in String := "");
105 (File : in File_Type;
106 Item : System.Address;
107 Size : in Interfaces.C_Streams.size_t;
108 From : in Positive_Count);
111 (File : in File_Type;
112 Item : System.Address;
113 Size : in Interfaces.C_Streams.size_t);
115 procedure Reset (File : in out File_Type; Mode : in FCB.File_Mode);
117 procedure Reset (File : in out File_Type);
119 procedure Set_Index (File : in File_Type; To : in Positive_Count);
121 function Size (File : in File_Type) return Count;
124 (File : in File_Type;
125 Item : System.Address;
126 Size : in Interfaces.C_Streams.size_t;
127 Zeroes : System.Storage_Elements.Storage_Array);
128 -- Note: Zeroes is the buffer of zeroes used to fill out partial records
130 end System.Direct_IO;