1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . D I R E C T _ I O --
10 -- Copyright (C) 1992-2001 Free Software Foundation, Inc. --
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. --
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. --
30 -- GNAT was originally developed by the GNAT team at New York University. --
31 -- Extensive contributions were provided by Ada Core Technologies Inc. --
33 ------------------------------------------------------------------------------
35 with Ada.IO_Exceptions; use Ada.IO_Exceptions;
36 with Interfaces.C_Streams; use Interfaces.C_Streams;
37 with System; use System;
39 with System.Soft_Links;
40 with Unchecked_Deallocation;
42 package body System.Direct_IO is
44 package FIO renames System.File_IO;
45 package SSL renames System.Soft_Links;
47 subtype AP is FCB.AFCB_Ptr;
48 use type FCB.Shared_Status_Type;
50 -----------------------
51 -- Local Subprograms --
52 -----------------------
54 procedure Set_Position (File : in File_Type);
55 -- Sets file position pointer according to value of current index
61 function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
62 pragma Warnings (Off, Control_Block);
65 return new Direct_AFCB;
72 -- No special processing required for Direct_IO close
74 procedure AFCB_Close (File : access Direct_AFCB) is
75 pragma Warnings (Off, File);
85 procedure AFCB_Free (File : access Direct_AFCB) is
87 type FCB_Ptr is access all Direct_AFCB;
89 FT : FCB_Ptr := FCB_Ptr (File);
92 Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);
103 (File : in out File_Type;
104 Mode : in FCB.File_Mode := FCB.Inout_File;
105 Name : in String := "";
106 Form : in String := "")
108 File_Control_Block : Direct_AFCB;
111 FIO.Open (File_Ptr => AP (File),
112 Dummy_FCB => File_Control_Block,
125 function End_Of_File (File : in File_Type) return Boolean is
127 FIO.Check_Read_Status (AP (File));
128 return Count (File.Index) > Size (File);
135 function Index (File : in File_Type) return Positive_Count is
137 FIO.Check_File_Open (AP (File));
138 return Count (File.Index);
146 (File : in out File_Type;
147 Mode : in FCB.File_Mode;
149 Form : in String := "")
151 File_Control_Block : Direct_AFCB;
154 FIO.Open (File_Ptr => AP (File),
155 Dummy_FCB => File_Control_Block,
169 (File : in File_Type;
171 Size : in Interfaces.C_Streams.size_t;
172 From : in Positive_Count)
175 Set_Index (File, From);
176 Read (File, Item, Size);
180 (File : in File_Type;
182 Size : in Interfaces.C_Streams.size_t)
185 FIO.Check_Read_Status (AP (File));
187 -- If last operation was not a read, or if in file sharing mode,
188 -- then reset the physical pointer of the file to match the index
189 -- We lock out task access over the two operations in this case.
191 if File.Last_Op /= Op_Read
192 or else File.Shared_Status = FCB.Yes
194 if End_Of_File (File) then
198 Locked_Processing : begin
201 FIO.Read_Buf (AP (File), Item, Size);
208 end Locked_Processing;
211 FIO.Read_Buf (AP (File), Item, Size);
214 File.Index := File.Index + 1;
216 -- Set last operation to read, unless we did not read a full record
217 -- (happens with the variant record case) in which case we set the
218 -- last operation as other, to force the file position to be reset
221 if File.Bytes = Size then
222 File.Last_Op := Op_Read;
224 File.Last_Op := Op_Other;
228 -- The following is the required overriding for Stream.Read, which is
229 -- not used, since we do not do Stream operations on Direct_IO files.
232 (File : in out Direct_AFCB;
233 Item : out Ada.Streams.Stream_Element_Array;
234 Last : out Ada.Streams.Stream_Element_Offset)
244 procedure Reset (File : in out File_Type; Mode : in FCB.File_Mode) is
246 FIO.Reset (AP (File), Mode);
248 File.Last_Op := Op_Read;
251 procedure Reset (File : in out File_Type) is
253 FIO.Reset (AP (File));
255 File.Last_Op := Op_Read;
262 procedure Set_Index (File : in File_Type; To : in Positive_Count) is
264 FIO.Check_File_Open (AP (File));
265 File.Index := Count (To);
266 File.Last_Op := Op_Other;
273 procedure Set_Position (File : in File_Type) is
276 (File.Stream, long (File.Bytes) *
277 long (File.Index - 1), SEEK_SET) /= 0
287 function Size (File : in File_Type) return Count is
289 FIO.Check_File_Open (AP (File));
290 File.Last_Op := Op_Other;
292 if fseek (File.Stream, 0, SEEK_END) /= 0 then
296 return Count (ftell (File.Stream) / long (File.Bytes));
306 Size : in Interfaces.C_Streams.size_t;
307 Zeroes : System.Storage_Elements.Storage_Array)
311 -- Do the actual write
313 procedure Do_Write is
315 FIO.Write_Buf (AP (File), Item, Size);
317 -- If we did not write the whole record (happens with the variant
318 -- record case), then fill out the rest of the record with zeroes.
319 -- This is cleaner in any case, and is required for the last
320 -- record, since otherwise the length of the file is wrong.
322 if File.Bytes > Size then
323 FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
327 -- Start of processing for Write
330 FIO.Check_Write_Status (AP (File));
332 -- If last operation was not a write, or if in file sharing mode,
333 -- then reset the physical pointer of the file to match the index
334 -- We lock out task access over the two operations in this case.
336 if File.Last_Op /= Op_Write
337 or else File.Shared_Status = FCB.Yes
339 Locked_Processing : begin
349 end Locked_Processing;
355 File.Index := File.Index + 1;
357 -- Set last operation to write, unless we did not read a full record
358 -- (happens with the variant record case) in which case we set the
359 -- last operation as other, to force the file position to be reset
360 -- on the next write.
362 if File.Bytes = Size then
363 File.Last_Op := Op_Write;
365 File.Last_Op := Op_Other;
369 -- The following is the required overriding for Stream.Write, which is
370 -- not used, since we do not do Stream operations on Direct_IO files.
373 (File : in out Direct_AFCB;
374 Item : in Ada.Streams.Stream_Element_Array)
380 end System.Direct_IO;