aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/libgnat/s-direio.adb
blob: be428c2ed8c3825616cf7ad823fdda28ec1d3d5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--                     S Y S T E M . D I R E C T _ I O                      --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2024, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Ada.IO_Exceptions;          use Ada.IO_Exceptions;
with Ada.Unchecked_Deallocation;
with Interfaces.C_Streams;       use Interfaces.C_Streams;
with System.CRTL;
with System.File_IO;
with System.Soft_Links;

package body System.Direct_IO is

   package FIO renames System.File_IO;
   package SSL renames System.Soft_Links;

   subtype AP is FCB.AFCB_Ptr;
   use type FCB.Shared_Status_Type;

   use type System.CRTL.int64;
   use type System.CRTL.size_t;

   -----------------------
   -- Local Subprograms --
   -----------------------

   procedure Set_Position (File : File_Type);
   --  Sets file position pointer according to value of current index

   -------------------
   -- AFCB_Allocate --
   -------------------

   function AFCB_Allocate (Control_Block : Direct_AFCB) return FCB.AFCB_Ptr is
      pragma Unreferenced (Control_Block);
   begin
      return new Direct_AFCB;
   end AFCB_Allocate;

   ----------------
   -- AFCB_Close --
   ----------------

   --  No special processing required for Direct_IO close

   procedure AFCB_Close (File : not null access Direct_AFCB) is
      pragma Unreferenced (File);
   begin
      null;
   end AFCB_Close;

   ---------------
   -- AFCB_Free --
   ---------------

   procedure AFCB_Free (File : not null access Direct_AFCB) is

      type FCB_Ptr is access all Direct_AFCB;

      FT : FCB_Ptr := FCB_Ptr (File);

      procedure Free is new
        Ada.Unchecked_Deallocation (Direct_AFCB, FCB_Ptr);

   begin
      Free (FT);
   end AFCB_Free;

   ------------
   -- Create --
   ------------

   procedure Create
     (File : in out File_Type;
      Mode : FCB.File_Mode := FCB.Inout_File;
      Name : String := "";
      Form : String := "")
   is
      Dummy_File_Control_Block : Direct_AFCB;
      pragma Warnings (Off, Dummy_File_Control_Block);
      --  Yes, we know this is never assigned a value, only the tag is used for
      --  dispatching purposes, so that's expected.

   begin
      FIO.Open (File_Ptr  => AP (File),
                Dummy_FCB => Dummy_File_Control_Block,
                Mode      => Mode,
                Name      => Name,
                Form      => Form,
                Amethod   => 'D',
                Creat     => True,
                Text      => False);
   end Create;

   -----------------
   -- End_Of_File --
   -----------------

   function End_Of_File (File : File_Type) return Boolean is
   begin
      FIO.Check_Read_Status (AP (File));
      return File.Index > Size (File);
   end End_Of_File;

   -----------
   -- Index --
   -----------

   function Index (File : File_Type) return Positive_Count is
   begin
      FIO.Check_File_Open (AP (File));
      return File.Index;
   end Index;

   ----------
   -- Open --
   ----------

   procedure Open
     (File : in out File_Type;
      Mode : FCB.File_Mode;
      Name : String;
      Form : String := "")
   is
      Dummy_File_Control_Block : Direct_AFCB;
      pragma Warnings (Off, Dummy_File_Control_Block);
      --  Yes, we know this is never assigned a value, only the tag is used for
      --  dispatching purposes, so that's expected.

   begin
      FIO.Open (File_Ptr  => AP (File),
                Dummy_FCB => Dummy_File_Control_Block,
                Mode      => Mode,
                Name      => Name,
                Form      => Form,
                Amethod   => 'D',
                Creat     => False,
                Text      => False);
   end Open;

   ----------
   -- Read --
   ----------

   procedure Read
     (File : File_Type;
      Item : Address;
      Size : Interfaces.C_Streams.size_t;
      From : Positive_Count)
   is
   begin
      Set_Index (File, From);
      Read (File, Item, Size);
   end Read;

   procedure Read
     (File : File_Type;
      Item : Address;
      Size : Interfaces.C_Streams.size_t)
   is
   begin
      FIO.Check_Read_Status (AP (File));

      --  If last operation was not a read, or if in file sharing mode,
      --  then reset the physical pointer of the file to match the index
      --  We lock out task access over the two operations in this case.

      if File.Last_Op /= Op_Read
        or else File.Shared_Status = FCB.Yes
      then
         if End_Of_File (File) then
            raise End_Error;
         end if;

         Locked_Processing : begin
            SSL.Lock_Task.all;
            Set_Position (File);
            FIO.Read_Buf (AP (File), Item, Size);
            SSL.Unlock_Task.all;

         exception
            when others =>
               SSL.Unlock_Task.all;
               raise;
         end Locked_Processing;

      else
         FIO.Read_Buf (AP (File), Item, Size);
      end if;

      File.Index := File.Index + 1;

      --  Set last operation to read, unless we did not read a full record
      --  (happens with the variant record case) in which case we set the
      --  last operation as other, to force the file position to be reset
      --  on the next read.

      File.Last_Op := (if File.Bytes = Size then Op_Read else Op_Other);
   end Read;

   --  The following is the required overriding for Stream.Read, which is
   --  not used, since we do not do Stream operations on Direct_IO files.

   procedure Read
     (File : in out Direct_AFCB;
      Item : out Ada.Streams.Stream_Element_Array;
      Last : out Ada.Streams.Stream_Element_Offset)
   is
   begin
      raise Program_Error;
   end Read;

   -----------
   -- Reset --
   -----------

   procedure Reset (File : in out File_Type; Mode : FCB.File_Mode) is
      pragma Warnings (Off, File);
      --  File is actually modified via Unrestricted_Access below, but
      --  GNAT will generate a warning anyway.
      --
      --  Note that we do not use pragma Unmodified here, since in -gnatc mode,
      --  GNAT will complain that File is modified for "File.Index := 1;"
   begin
      FIO.Reset (AP (File)'Unrestricted_Access, Mode);
      File.Index := 1;
      File.Last_Op := Op_Read;
   end Reset;

   procedure Reset (File : in out File_Type) is
      pragma Warnings (Off, File);
      --  See above (other Reset procedure) for explanations on this pragma
   begin
      FIO.Reset (AP (File)'Unrestricted_Access);
      File.Index := 1;
      File.Last_Op := Op_Read;
   end Reset;

   ---------------
   -- Set_Index --
   ---------------

   procedure Set_Index (File : File_Type; To : Positive_Count) is
   begin
      FIO.Check_File_Open (AP (File));
      File.Index := Count (To);
      File.Last_Op := Op_Other;
   end Set_Index;

   ------------------
   -- Set_Position --
   ------------------

   procedure Set_Position (File : File_Type) is
      R : int;
   begin
      R :=
        fseek64
          (File.Stream, int64 (File.Bytes) * int64 (File.Index - 1), SEEK_SET);

      if R /= 0 then
         raise Use_Error;
      end if;
   end Set_Position;

   ----------
   -- Size --
   ----------

   function Size (File : File_Type) return Count is
      Pos : int64;

   begin
      FIO.Check_File_Open (AP (File));
      File.Last_Op := Op_Other;

      if fseek64 (File.Stream, 0, SEEK_END) /= 0 then
         raise Device_Error;
      end if;

      Pos := ftell64 (File.Stream);

      if Pos = -1 then
         raise Use_Error;
      end if;

      return Count (Pos / int64 (File.Bytes));
   end Size;

   -----------
   -- Write --
   -----------

   procedure Write
     (File   : File_Type;
      Item   : Address;
      Size   : Interfaces.C_Streams.size_t;
      Zeroes : System.Storage_Elements.Storage_Array)

   is
      procedure Do_Write;
      --  Do the actual write

      --------------
      -- Do_Write --
      --------------

      procedure Do_Write is
      begin
         FIO.Write_Buf (AP (File), Item, Size);

         --  If we did not write the whole record (happens with the variant
         --  record case), then fill out the rest of the record with zeroes.
         --  This is cleaner in any case, and is required for the last
         --  record, since otherwise the length of the file is wrong.

         if File.Bytes > Size then
            FIO.Write_Buf (AP (File), Zeroes'Address, File.Bytes - Size);
         end if;
      end Do_Write;

   --  Start of processing for Write

   begin
      FIO.Check_Write_Status (AP (File));

      --  If last operation was not a write, or if in file sharing mode,
      --  then reset the physical pointer of the file to match the index
      --  We lock out task access over the two operations in this case.

      if File.Last_Op /= Op_Write
        or else File.Shared_Status = FCB.Yes
      then
         Locked_Processing : begin
            SSL.Lock_Task.all;
            Set_Position (File);
            Do_Write;
            SSL.Unlock_Task.all;

         exception
            when others =>
               SSL.Unlock_Task.all;
               raise;
         end Locked_Processing;

      else
         Do_Write;
      end if;

      File.Index := File.Index + 1;

      --  Set last operation to write, unless we did not read a full record
      --  (happens with the variant record case) in which case we set the
      --  last operation as other, to force the file position to be reset
      --  on the next write.

      File.Last_Op := (if File.Bytes = Size then Op_Write else Op_Other);
   end Write;

   --  The following is the required overriding for Stream.Write, which is
   --  not used, since we do not do Stream operations on Direct_IO files.

   procedure Write
     (File : in out Direct_AFCB;
      Item : Ada.Streams.Stream_Element_Array)
   is
   begin
      raise Program_Error;
   end Write;

end System.Direct_IO;