1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . D I R E C T _ I O --
9 -- Copyright (C) 1992-2003 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;
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 use type System.CRTL.long;
51 use type System.CRTL.size_t;
53 -----------------------
54 -- Local Subprograms --
55 -----------------------
57 procedure Set_Position (File : in File_Type);
58 -- Sets file position pointer according to value of current index
64 function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
65 pragma Unreferenced (Control_Block);
68 return new Direct_AFCB;
75 -- No special processing required for Direct_IO close
77 procedure AFCB_Close (File : access Direct_AFCB) is
78 pragma Unreferenced (File);
88 procedure AFCB_Free (File : access Direct_AFCB) is
90 type FCB_Ptr is access all Direct_AFCB;
92 FT : FCB_Ptr := FCB_Ptr (File);
95 Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);
106 (File : in out File_Type;
107 Mode : in FCB.File_Mode := FCB.Inout_File;
108 Name : in String := "";
109 Form : in String := "")
111 Dummy_File_Control_Block : Direct_AFCB;
112 pragma Warnings (Off, Dummy_File_Control_Block);
113 -- Yes, we know this is never assigned a value, only the tag
114 -- is used for dispatching purposes, so that's expected.
117 FIO.Open (File_Ptr => AP (File),
118 Dummy_FCB => Dummy_File_Control_Block,
131 function End_Of_File (File : in File_Type) return Boolean is
133 FIO.Check_Read_Status (AP (File));
134 return Count (File.Index) > Size (File);
141 function Index (File : in File_Type) return Positive_Count is
143 FIO.Check_File_Open (AP (File));
144 return Count (File.Index);
152 (File : in out File_Type;
153 Mode : in FCB.File_Mode;
155 Form : in String := "")
157 Dummy_File_Control_Block : Direct_AFCB;
158 pragma Warnings (Off, Dummy_File_Control_Block);
159 -- Yes, we know this is never assigned a value, only the tag
160 -- is used for dispatching purposes, so that's expected.
163 FIO.Open (File_Ptr => AP (File),
164 Dummy_FCB => Dummy_File_Control_Block,
178 (File : in File_Type;
180 Size : in Interfaces.C_Streams.size_t;
181 From : in Positive_Count)
184 Set_Index (File, From);
185 Read (File, Item, Size);
189 (File : in File_Type;
191 Size : in Interfaces.C_Streams.size_t)
194 FIO.Check_Read_Status (AP (File));
196 -- If last operation was not a read, or if in file sharing mode,
197 -- then reset the physical pointer of the file to match the index
198 -- We lock out task access over the two operations in this case.
200 if File.Last_Op /= Op_Read
201 or else File.Shared_Status = FCB.Yes
203 if End_Of_File (File) then
207 Locked_Processing : begin
210 FIO.Read_Buf (AP (File), Item, Size);
217 end Locked_Processing;
220 FIO.Read_Buf (AP (File), Item, Size);
223 File.Index := File.Index + 1;
225 -- Set last operation to read, unless we did not read a full record
226 -- (happens with the variant record case) in which case we set the
227 -- last operation as other, to force the file position to be reset
230 if File.Bytes = Size then
231 File.Last_Op := Op_Read;
233 File.Last_Op := Op_Other;
237 -- The following is the required overriding for Stream.Read, which is
238 -- not used, since we do not do Stream operations on Direct_IO files.
241 (File : in out Direct_AFCB;
242 Item : out Ada.Streams.Stream_Element_Array;
243 Last : out Ada.Streams.Stream_Element_Offset)
253 procedure Reset (File : in out File_Type; Mode : in FCB.File_Mode) is
255 FIO.Reset (AP (File), Mode);
257 File.Last_Op := Op_Read;
260 procedure Reset (File : in out File_Type) is
262 FIO.Reset (AP (File));
264 File.Last_Op := Op_Read;
271 procedure Set_Index (File : in File_Type; To : in Positive_Count) is
273 FIO.Check_File_Open (AP (File));
274 File.Index := Count (To);
275 File.Last_Op := Op_Other;
282 procedure Set_Position (File : in File_Type) is
285 (File.Stream, long (File.Bytes) *
286 long (File.Index - 1), SEEK_SET) /= 0
296 function Size (File : in File_Type) return Count is
298 FIO.Check_File_Open (AP (File));
299 File.Last_Op := Op_Other;
301 if fseek (File.Stream, 0, SEEK_END) /= 0 then
305 return Count (ftell (File.Stream) / long (File.Bytes));
315 Size : in Interfaces.C_Streams.size_t;
316 Zeroes : System.Storage_Elements.Storage_Array)
320 -- Do the actual write
322 procedure Do_Write is
324 FIO.Write_Buf (AP (File), Item, Size);
326 -- If we did not write the whole record (happens with the variant
327 -- record case), then fill out the rest of the record with zeroes.
328 -- This is cleaner in any case, and is required for the last
329 -- record, since otherwise the length of the file is wrong.
331 if File.Bytes > Size then
332 FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
336 -- Start of processing for Write
339 FIO.Check_Write_Status (AP (File));
341 -- If last operation was not a write, or if in file sharing mode,
342 -- then reset the physical pointer of the file to match the index
343 -- We lock out task access over the two operations in this case.
345 if File.Last_Op /= Op_Write
346 or else File.Shared_Status = FCB.Yes
348 Locked_Processing : begin
358 end Locked_Processing;
364 File.Index := File.Index + 1;
366 -- Set last operation to write, unless we did not read a full record
367 -- (happens with the variant record case) in which case we set the
368 -- last operation as other, to force the file position to be reset
369 -- on the next write.
371 if File.Bytes = Size then
372 File.Last_Op := Op_Write;
374 File.Last_Op := Op_Other;
378 -- The following is the required overriding for Stream.Write, which is
379 -- not used, since we do not do Stream operations on Direct_IO files.
382 (File : in out Direct_AFCB;
383 Item : in Ada.Streams.Stream_Element_Array)
389 end System.Direct_IO;