1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . S T R E A M S . S T R E A M _ I O --
9 -- Copyright (C) 1992-2008, Free Software Foundation, Inc. --
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. --
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 2, 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. See the GNU General Public License --
21 -- for more details. You should have received a copy of the GNU General --
22 -- Public License distributed with GNAT; see file COPYING. If not, write --
23 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
24 -- Boston, MA 02110-1301, USA. --
26 -- As a special exception, if other files instantiate generics from this --
27 -- unit, or you link this unit with other files to produce an executable, --
28 -- this unit does not by itself cause the resulting executable to be --
29 -- covered by the GNU General Public License. This exception does not --
30 -- however invalidate any other reasons why the executable file might be --
31 -- covered by the GNU Public License. --
33 -- GNAT was originally developed by the GNAT team at New York University. --
34 -- Extensive contributions were provided by Ada Core Technologies Inc. --
36 ------------------------------------------------------------------------------
38 with Ada
.IO_Exceptions
;
39 with System
.File_Control_Block
;
41 package Ada
.Streams
.Stream_IO
is
43 type Stream_Access
is access all Root_Stream_Type
'Class;
45 type File_Type
is limited private;
47 type File_Mode
is (In_File
, Out_File
, Append_File
);
49 -- The following representation clause allows the use of unchecked
50 -- conversion for rapid translation between the File_Mode type
51 -- used in this package and System.File_IO.
54 (In_File
=> 0, -- System.File_IO.File_Mode'Pos (In_File)
55 Out_File
=> 2, -- System.File_IO.File_Mode'Pos (Out_File)
56 Append_File
=> 3); -- System.File_IO.File_Mode'Pos (Append_File)
58 type Count
is new Stream_Element_Offset
59 range 0 .. Stream_Element_Offset
'Last;
61 subtype Positive_Count
is Count
range 1 .. Count
'Last;
62 -- Index into file, in stream elements
69 (File
: in out File_Type
;
70 Mode
: File_Mode
:= Out_File
;
75 (File
: in out File_Type
;
80 procedure Close
(File
: in out File_Type
);
81 procedure Delete
(File
: in out File_Type
);
82 procedure Reset
(File
: in out File_Type
; Mode
: File_Mode
);
83 procedure Reset
(File
: in out File_Type
);
85 function Mode
(File
: File_Type
) return File_Mode
;
86 function Name
(File
: File_Type
) return String;
87 function Form
(File
: File_Type
) return String;
89 function Is_Open
(File
: File_Type
) return Boolean;
90 function End_Of_File
(File
: File_Type
) return Boolean;
92 function Stream
(File
: File_Type
) return Stream_Access
;
94 -----------------------------
95 -- Input-Output Operations --
96 -----------------------------
100 Item
: out Stream_Element_Array
;
101 Last
: out Stream_Element_Offset
;
102 From
: Positive_Count
);
106 Item
: out Stream_Element_Array
;
107 Last
: out Stream_Element_Offset
);
111 Item
: Stream_Element_Array
;
112 To
: Positive_Count
);
116 Item
: Stream_Element_Array
);
118 ----------------------------------------
119 -- Operations on Position within File --
120 ----------------------------------------
122 procedure Set_Index
(File
: File_Type
; To
: Positive_Count
);
124 function Index
(File
: File_Type
) return Positive_Count
;
125 function Size
(File
: File_Type
) return Count
;
127 procedure Set_Mode
(File
: in out File_Type
; Mode
: File_Mode
);
129 -- Note: The parameter file is IN OUT in the RM, but this is clearly
130 -- an oversight, and was intended to be IN, see AI95-00057.
132 procedure Flush
(File
: File_Type
);
138 Status_Error
: exception renames IO_Exceptions
.Status_Error
;
139 Mode_Error
: exception renames IO_Exceptions
.Mode_Error
;
140 Name_Error
: exception renames IO_Exceptions
.Name_Error
;
141 Use_Error
: exception renames IO_Exceptions
.Use_Error
;
142 Device_Error
: exception renames IO_Exceptions
.Device_Error
;
143 End_Error
: exception renames IO_Exceptions
.End_Error
;
144 Data_Error
: exception renames IO_Exceptions
.Data_Error
;
148 -- The following procedures have a File_Type formal of mode IN OUT because
149 -- they may close the original file. The Close operation may raise an
150 -- exception, but in that case we want any assignment to the formal to
151 -- be effective anyway, so it must be passed by reference (or the caller
152 -- will be left with a dangling pointer).
154 pragma Export_Procedure
157 Mechanism
=> Reference
);
158 pragma Export_Procedure
161 Mechanism
=> Reference
);
162 pragma Export_Procedure
165 Parameter_Types
=> (File_Type
),
166 Mechanism
=> Reference
);
167 pragma Export_Procedure
170 Parameter_Types
=> (File_Type
, File_Mode
),
171 Mechanism
=> (File
=> Reference
));
172 pragma Export_Procedure
173 (Internal
=> Set_Mode
,
175 Mechanism
=> (File
=> Reference
));
177 package FCB
renames System
.File_Control_Block
;
179 -----------------------------
180 -- Stream_IO Control Block --
181 -----------------------------
183 type Operation
is (Op_Read
, Op_Write
, Op_Other
);
184 -- Type used to record last operation (to optimize sequential operations)
186 type Stream_AFCB
is new FCB
.AFCB
with record
188 -- Current Index value
190 File_Size
: Stream_Element_Offset
:= -1;
191 -- Cached value of File_Size, so that we do not keep recomputing it
192 -- when not necessary (otherwise End_Of_File becomes gruesomely slow).
193 -- A value of minus one means that there is no cached value.
195 Last_Op
: Operation
:= Op_Other
;
196 -- Last operation performed on file, used to avoid unnecessary
197 -- repositioning between successive read or write operations.
199 Update_Mode
: Boolean := False;
200 -- Set if the mode is changed from write to read or vice versa.
201 -- Indicates that the file has been reopened in update mode.
205 type File_Type
is access all Stream_AFCB
;
207 function AFCB_Allocate
(Control_Block
: Stream_AFCB
) return FCB
.AFCB_Ptr
;
209 procedure AFCB_Close
(File
: not null access Stream_AFCB
);
210 procedure AFCB_Free
(File
: not null access Stream_AFCB
);
213 (File
: in out Stream_AFCB
;
214 Item
: out Ada
.Streams
.Stream_Element_Array
;
215 Last
: out Ada
.Streams
.Stream_Element_Offset
);
216 -- Read operation used when Stream_IO file is treated directly as Stream
219 (File
: in out Stream_AFCB
;
220 Item
: Ada
.Streams
.Stream_Element_Array
);
221 -- Write operation used when Stream_IO file is treated directly as Stream
223 end Ada
.Streams
.Stream_IO
;