1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . D I R E C T _ I O --
9 -- Copyright (C) 1992-2009, 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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 with Ada.IO_Exceptions; use Ada.IO_Exceptions;
33 with Interfaces.C_Streams; use Interfaces.C_Streams;
34 with System; use System;
37 with System.Soft_Links;
38 with Ada.Unchecked_Deallocation;
40 package body System.Direct_IO is
42 package FIO renames System.File_IO;
43 package SSL renames System.Soft_Links;
45 subtype AP is FCB.AFCB_Ptr;
46 use type FCB.Shared_Status_Type;
48 use type System.CRTL.long;
49 use type System.CRTL.size_t;
51 -----------------------
52 -- Local Subprograms --
53 -----------------------
55 procedure Set_Position (File : File_Type);
56 -- Sets file position pointer according to value of current index
62 function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
63 pragma Unreferenced (Control_Block);
65 return new Direct_AFCB;
72 -- No special processing required for Direct_IO close
74 procedure AFCB_Close (File : not null access Direct_AFCB) is
75 pragma Unreferenced (File);
84 procedure AFCB_Free (File : not null access Direct_AFCB) is
86 type FCB_Ptr is access all Direct_AFCB;
88 FT : FCB_Ptr := FCB_Ptr (File);
91 Ada.Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);
102 (File : in out File_Type;
103 Mode : FCB.File_Mode := FCB.Inout_File;
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 is used for
110 -- 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 : File_Type) return Boolean is
129 FIO.Check_Read_Status (AP (File));
130 return Count (File.Index) > Size (File);
137 function Index (File : 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 : FCB.File_Mode;
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 is used for
156 -- dispatching purposes, so that's expected.
159 FIO.Open (File_Ptr => AP (File),
160 Dummy_FCB => Dummy_File_Control_Block,
176 Size : Interfaces.C_Streams.size_t;
177 From : Positive_Count)
180 Set_Index (File, From);
181 Read (File, Item, Size);
187 Size : 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 File.Last_Op := (if File.Bytes = Size then Op_Read else Op_Other);
229 -- The following is the required overriding for Stream.Read, which is
230 -- not used, since we do not do Stream operations on Direct_IO files.
233 (File : in out Direct_AFCB;
234 Item : out Ada.Streams.Stream_Element_Array;
235 Last : out Ada.Streams.Stream_Element_Offset)
245 procedure Reset (File : in out File_Type; Mode : FCB.File_Mode) is
246 pragma Warnings (Off, File);
247 -- File is actually modified via Unrestricted_Access below, but
248 -- GNAT will generate a warning anyway.
250 -- Note that we do not use pragma Unmodified here, since in -gnatc mode,
251 -- GNAT will complain that File is modified for "File.Index := 1;"
253 FIO.Reset (AP (File)'Unrestricted_Access, Mode);
255 File.Last_Op := Op_Read;
258 procedure Reset (File : in out File_Type) is
259 pragma Warnings (Off, File);
260 -- See above (other Reset procedure) for explanations on this pragma
262 FIO.Reset (AP (File)'Unrestricted_Access);
264 File.Last_Op := Op_Read;
271 procedure Set_Index (File : File_Type; To : 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 : File_Type) is
285 (File.Stream, long (File.Bytes) *
286 long (File.Index - 1), SEEK_SET) /= 0
296 function Size (File : 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 : Interfaces.C_Streams.size_t;
316 Zeroes : System.Storage_Elements.Storage_Array)
320 -- Do the actual write
326 procedure Do_Write is
328 FIO.Write_Buf (AP (File), Item, Size);
330 -- If we did not write the whole record (happens with the variant
331 -- record case), then fill out the rest of the record with zeroes.
332 -- This is cleaner in any case, and is required for the last
333 -- record, since otherwise the length of the file is wrong.
335 if File.Bytes > Size then
336 FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
340 -- Start of processing for Write
343 FIO.Check_Write_Status (AP (File));
345 -- If last operation was not a write, or if in file sharing mode,
346 -- then reset the physical pointer of the file to match the index
347 -- We lock out task access over the two operations in this case.
349 if File.Last_Op /= Op_Write
350 or else File.Shared_Status = FCB.Yes
352 Locked_Processing : begin
362 end Locked_Processing;
368 File.Index := File.Index + 1;
370 -- Set last operation to write, unless we did not read a full record
371 -- (happens with the variant record case) in which case we set the
372 -- last operation as other, to force the file position to be reset
373 -- on the next write.
375 File.Last_Op := (if File.Bytes = Size then Op_Write else 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 : Ada.Streams.Stream_Element_Array)
389 end System.Direct_IO;