1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . D I R E C T _ I O --
9 -- Copyright (C) 1992-2002 Free Software Foundation, Inc. --
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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Ada.IO_Exceptions; use Ada.IO_Exceptions;
35 with Interfaces.C_Streams; use Interfaces.C_Streams;
36 with System; use System;
38 with System.Soft_Links;
39 with Unchecked_Deallocation;
41 package body System.Direct_IO is
43 package FIO renames System.File_IO;
44 package SSL renames System.Soft_Links;
46 subtype AP is FCB.AFCB_Ptr;
47 use type FCB.Shared_Status_Type;
49 -----------------------
50 -- Local Subprograms --
51 -----------------------
53 procedure Set_Position (File : in File_Type);
54 -- Sets file position pointer according to value of current index
60 function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
61 pragma Unreferenced (Control_Block);
64 return new Direct_AFCB;
71 -- No special processing required for Direct_IO close
73 procedure AFCB_Close (File : access Direct_AFCB) is
74 pragma Unreferenced (File);
84 procedure AFCB_Free (File : access Direct_AFCB) is
86 type FCB_Ptr is access all Direct_AFCB;
88 FT : FCB_Ptr := FCB_Ptr (File);
91 Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);
102 (File : in out File_Type;
103 Mode : in FCB.File_Mode := FCB.Inout_File;
104 Name : in String := "";
105 Form : in String := "")
107 Dummy_File_Control_Block : Direct_AFCB;
108 pragma Warnings (Off, Dummy_File_Control_Block);
109 -- Yes, we know this is never assigned a value, only the tag
110 -- is used for dispatching purposes, so that's expected.
113 FIO.Open (File_Ptr => AP (File),
114 Dummy_FCB => Dummy_File_Control_Block,
127 function End_Of_File (File : in File_Type) return Boolean is
129 FIO.Check_Read_Status (AP (File));
130 return Count (File.Index) > Size (File);
137 function Index (File : in File_Type) return Positive_Count is
139 FIO.Check_File_Open (AP (File));
140 return Count (File.Index);
148 (File : in out File_Type;
149 Mode : in FCB.File_Mode;
151 Form : in String := "")
153 Dummy_File_Control_Block : Direct_AFCB;
154 pragma Warnings (Off, Dummy_File_Control_Block);
155 -- Yes, we know this is never assigned a value, only the tag
156 -- is used for dispatching purposes, so that's expected.
159 FIO.Open (File_Ptr => AP (File),
160 Dummy_FCB => Dummy_File_Control_Block,
174 (File : in File_Type;
176 Size : in Interfaces.C_Streams.size_t;
177 From : in Positive_Count)
180 Set_Index (File, From);
181 Read (File, Item, Size);
185 (File : in File_Type;
187 Size : in Interfaces.C_Streams.size_t)
190 FIO.Check_Read_Status (AP (File));
192 -- If last operation was not a read, or if in file sharing mode,
193 -- then reset the physical pointer of the file to match the index
194 -- We lock out task access over the two operations in this case.
196 if File.Last_Op /= Op_Read
197 or else File.Shared_Status = FCB.Yes
199 if End_Of_File (File) then
203 Locked_Processing : begin
206 FIO.Read_Buf (AP (File), Item, Size);
213 end Locked_Processing;
216 FIO.Read_Buf (AP (File), Item, Size);
219 File.Index := File.Index + 1;
221 -- Set last operation to read, unless we did not read a full record
222 -- (happens with the variant record case) in which case we set the
223 -- last operation as other, to force the file position to be reset
226 if File.Bytes = Size then
227 File.Last_Op := Op_Read;
229 File.Last_Op := Op_Other;
233 -- The following is the required overriding for Stream.Read, which is
234 -- not used, since we do not do Stream operations on Direct_IO files.
237 (File : in out Direct_AFCB;
238 Item : out Ada.Streams.Stream_Element_Array;
239 Last : out Ada.Streams.Stream_Element_Offset)
249 procedure Reset (File : in out File_Type; Mode : in FCB.File_Mode) is
251 FIO.Reset (AP (File), Mode);
253 File.Last_Op := Op_Read;
256 procedure Reset (File : in out File_Type) is
258 FIO.Reset (AP (File));
260 File.Last_Op := Op_Read;
267 procedure Set_Index (File : in File_Type; To : in Positive_Count) is
269 FIO.Check_File_Open (AP (File));
270 File.Index := Count (To);
271 File.Last_Op := Op_Other;
278 procedure Set_Position (File : in File_Type) is
281 (File.Stream, long (File.Bytes) *
282 long (File.Index - 1), SEEK_SET) /= 0
292 function Size (File : in File_Type) return Count is
294 FIO.Check_File_Open (AP (File));
295 File.Last_Op := Op_Other;
297 if fseek (File.Stream, 0, SEEK_END) /= 0 then
301 return Count (ftell (File.Stream) / long (File.Bytes));
311 Size : in Interfaces.C_Streams.size_t;
312 Zeroes : System.Storage_Elements.Storage_Array)
316 -- Do the actual write
318 procedure Do_Write is
320 FIO.Write_Buf (AP (File), Item, Size);
322 -- If we did not write the whole record (happens with the variant
323 -- record case), then fill out the rest of the record with zeroes.
324 -- This is cleaner in any case, and is required for the last
325 -- record, since otherwise the length of the file is wrong.
327 if File.Bytes > Size then
328 FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
332 -- Start of processing for Write
335 FIO.Check_Write_Status (AP (File));
337 -- If last operation was not a write, or if in file sharing mode,
338 -- then reset the physical pointer of the file to match the index
339 -- We lock out task access over the two operations in this case.
341 if File.Last_Op /= Op_Write
342 or else File.Shared_Status = FCB.Yes
344 Locked_Processing : begin
354 end Locked_Processing;
360 File.Index := File.Index + 1;
362 -- Set last operation to write, unless we did not read a full record
363 -- (happens with the variant record case) in which case we set the
364 -- last operation as other, to force the file position to be reset
365 -- on the next write.
367 if File.Bytes = Size then
368 File.Last_Op := Op_Write;
370 File.Last_Op := Op_Other;
374 -- The following is the required overriding for Stream.Write, which is
375 -- not used, since we do not do Stream operations on Direct_IO files.
378 (File : in out Direct_AFCB;
379 Item : in Ada.Streams.Stream_Element_Array)
385 end System.Direct_IO;