aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/gprep.adb
blob: c4bf8e91a522f7842cbcec9cc0519ca4affccaa8 (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
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                                G P R E P                                 --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2002-2014, 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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Atree;    use Atree;
with Csets;
with Errutil;
with Namet;    use Namet;
with Opt;
with Osint;    use Osint;
with Output;   use Output;
with Prep;     use Prep;
with Scng;
with Sinput.C;
with Snames;
with Stringt;  use Stringt;
with Switch;   use Switch;
with Types;    use Types;

with Ada.Command_Line; use Ada.Command_Line;
with Ada.Text_IO;      use Ada.Text_IO;

with GNAT.Case_Util;            use GNAT.Case_Util;
with GNAT.Command_Line;
with GNAT.Directory_Operations; use GNAT.Directory_Operations;

with System.OS_Lib; use System.OS_Lib;

package body GPrep is

   Copyright_Displayed : Boolean := False;
   --  Used to prevent multiple displays of the copyright notice

   ------------------------
   -- Argument Line Data --
   ------------------------

   Unix_Line_Terminators : Boolean := False;
   --  Set to True with option -T

   type String_Array is array (Boolean) of String_Access;
   Yes_No : constant String_Array :=
     (False => new String'("YES"),
      True  => new String'("NO"));

   Infile_Name  : Name_Id := No_Name;
   Outfile_Name : Name_Id := No_Name;
   Deffile_Name : Name_Id := No_Name;

   Output_Directory : Name_Id := No_Name;
   --  Used when the specified output is an existing directory

   Input_Directory : Name_Id := No_Name;
   --  Used when the specified input and output are existing directories

   Source_Ref_Pragma : Boolean := False;
   --  Record command line options (set if -r switch set)

   Text_Outfile : aliased Ada.Text_IO.File_Type;
   Outfile      : constant File_Access := Text_Outfile'Access;

   File_Name_Buffer_Initial_Size : constant := 50;
   File_Name_Buffer : String_Access :=
                        new String (1 .. File_Name_Buffer_Initial_Size);
   --  A buffer to build output file names from input file names

   -----------------
   -- Subprograms --
   -----------------

   procedure Display_Copyright;
   --  Display the copyright notice

   procedure Post_Scan;
   --  Null procedure, needed by instantiation of Scng below

   package Scanner is new Scng
     (Post_Scan,
      Errutil.Error_Msg,
      Errutil.Error_Msg_S,
      Errutil.Error_Msg_SC,
      Errutil.Error_Msg_SP,
      Errutil.Style);
   --  The scanner for the preprocessor

   function Is_ASCII_Letter (C : Character) return Boolean;
   --  True if C is in 'a' .. 'z' or in 'A' .. 'Z'

   procedure Double_File_Name_Buffer;
   --  Double the size of the file name buffer

   procedure Preprocess_Infile_Name;
   --  When the specified output is a directory, preprocess the infile name
   --  for symbol substitution, to get the output file name.

   procedure Process_Files;
   --  Process the single input file or all the files in the directory tree
   --  rooted at the input directory.

   procedure Process_Command_Line_Symbol_Definition (S : String);
   --  Process a -D switch on the command line

   procedure Put_Char_To_Outfile (C : Character);
   --  Output one character to the output file. Used to initialize the
   --  preprocessor.

   procedure New_EOL_To_Outfile;
   --  Output a new line to the output file. Used to initialize the
   --  preprocessor.

   procedure Scan_Command_Line;
   --  Scan the switches and the file names

   procedure Usage;
   --  Display the usage

   -----------------------
   -- Display_Copyright --
   -----------------------

   procedure Display_Copyright is
   begin
      if not Copyright_Displayed then
         Display_Version ("GNAT Preprocessor", "1996");
         Copyright_Displayed := True;
      end if;
   end Display_Copyright;

   -----------------------------
   -- Double_File_Name_Buffer --
   -----------------------------

   procedure Double_File_Name_Buffer is
      New_Buffer : constant String_Access :=
                     new String (1 .. 2 * File_Name_Buffer'Length);
   begin
      New_Buffer (File_Name_Buffer'Range) := File_Name_Buffer.all;
      Free (File_Name_Buffer);
      File_Name_Buffer := New_Buffer;
   end Double_File_Name_Buffer;

   --------------
   -- Gnatprep --
   --------------

   procedure Gnatprep is
   begin
      --  Do some initializations (order is important here)

      Csets.Initialize;
      Snames.Initialize;
      Stringt.Initialize;
      Prep.Initialize;

      --  Initialize the preprocessor

      Prep.Setup_Hooks
        (Error_Msg         => Errutil.Error_Msg'Access,
         Scan              => Scanner.Scan'Access,
         Set_Ignore_Errors => Errutil.Set_Ignore_Errors'Access,
         Put_Char          => Put_Char_To_Outfile'Access,
         New_EOL           => New_EOL_To_Outfile'Access);

      --  Set the scanner characteristics for the preprocessor

      Scanner.Set_Special_Character ('#');
      Scanner.Set_Special_Character ('$');
      Scanner.Set_End_Of_Line_As_Token (True);

      --  Initialize the mapping table of symbols to values

      Prep.Symbol_Table.Init (Prep.Mapping);

      --  Parse the switches and arguments

      Scan_Command_Line;

      if Opt.Verbose_Mode then
         Display_Copyright;
      end if;

      --  Test we had all the arguments needed

      if Infile_Name = No_Name then

         --  No input file specified, just output the usage and exit

         if Argument_Count = 0 then
            Usage;
         else
            GNAT.Command_Line.Try_Help;
         end if;

         return;

      elsif Outfile_Name = No_Name then

         --  No output file specified, exit

         GNAT.Command_Line.Try_Help;
         return;
      end if;

      --  If a pragma Source_File_Name, we need to keep line numbers. So, if
      --  the deleted lines are not put as comment, we must output them as
      --  blank lines.

      if Source_Ref_Pragma and (not Opt.Comment_Deleted_Lines) then
         Opt.Blank_Deleted_Lines := True;
      end if;

      --  If we have a definition file, parse it

      if Deffile_Name /= No_Name then
         declare
            Deffile : Source_File_Index;

         begin
            Errutil.Initialize;
            Deffile := Sinput.C.Load_File (Get_Name_String (Deffile_Name));

            --  Set Main_Source_File to the definition file for the benefit of
            --  Errutil.Finalize.

            Sinput.Main_Source_File := Deffile;

            if Deffile = No_Source_File then
               Fail ("unable to find definition file """
                     & Get_Name_String (Deffile_Name)
                     & """");
            end if;

            Scanner.Initialize_Scanner (Deffile);

            Prep.Parse_Def_File;
         end;
      end if;

      --  If there are errors in the definition file, output them and exit

      if Total_Errors_Detected > 0 then
         Errutil.Finalize (Source_Type => "definition");
         Fail ("errors in definition file """
               & Get_Name_String (Deffile_Name)
               & """");
      end if;

      --  If -s switch was specified, print a sorted list of symbol names and
      --  values, if any.

      if Opt.List_Preprocessing_Symbols then
         Prep.List_Symbols (Foreword => "");
      end if;

      Output_Directory := No_Name;
      Input_Directory  := No_Name;

      --  Check if the specified output is an existing directory

      if Is_Directory (Get_Name_String (Outfile_Name)) then
         Output_Directory := Outfile_Name;

         --  As the output is an existing directory, check if the input too
         --  is a directory.

         if Is_Directory (Get_Name_String (Infile_Name)) then
            Input_Directory := Infile_Name;
         end if;
      end if;

      --  And process the single input or the files in the directory tree
      --  rooted at the input directory.

      Process_Files;
   end Gnatprep;

   ---------------------
   -- Is_ASCII_Letter --
   ---------------------

   function Is_ASCII_Letter (C : Character) return Boolean is
   begin
      return C in 'A' .. 'Z' or else C in 'a' .. 'z';
   end Is_ASCII_Letter;

   ------------------------
   -- New_EOL_To_Outfile --
   ------------------------

   procedure New_EOL_To_Outfile is
   begin
      New_Line (Outfile.all);
   end New_EOL_To_Outfile;

   ---------------
   -- Post_Scan --
   ---------------

   procedure Post_Scan is
   begin
      null;
   end Post_Scan;

   ----------------------------
   -- Preprocess_Infile_Name --
   ----------------------------

   procedure Preprocess_Infile_Name is
      Len    : Natural;
      First  : Positive;
      Last   : Natural;
      Symbol : Name_Id;
      Data   : Symbol_Data;

   begin
      --  Initialize the buffer with the name of the input file

      Get_Name_String (Infile_Name);
      Len := Name_Len;

      while File_Name_Buffer'Length < Len loop
         Double_File_Name_Buffer;
      end loop;

      File_Name_Buffer (1 .. Len) := Name_Buffer (1 .. Len);

      --  Look for possible symbols in the file name

      First := 1;
      while First < Len loop

         --  A symbol starts with a dollar sign followed by a letter

         if File_Name_Buffer (First) = '$' and then
           Is_ASCII_Letter (File_Name_Buffer (First + 1))
         then
            Last := First + 1;

            --  Find the last letter of the symbol

            while Last < Len and then
               Is_ASCII_Letter (File_Name_Buffer (Last + 1))
            loop
               Last := Last + 1;
            end loop;

            --  Get the symbol name id

            Name_Len := Last - First;
            Name_Buffer (1 .. Name_Len) :=
              File_Name_Buffer (First + 1 .. Last);
            To_Lower (Name_Buffer (1 .. Name_Len));
            Symbol := Name_Find;

            --  And look for this symbol name in the symbol table

            for Index in 1 .. Symbol_Table.Last (Mapping) loop
               Data := Mapping.Table (Index);

               if Data.Symbol = Symbol then

                  --  We found the symbol. If its value is not a string,
                  --  replace the symbol in the file name with the value of
                  --  the symbol.

                  if not Data.Is_A_String then
                     String_To_Name_Buffer (Data.Value);

                     declare
                        Sym_Len : constant Positive := Last - First + 1;
                        Offset  : constant Integer := Name_Len - Sym_Len;
                        New_Len : constant Natural := Len + Offset;

                     begin
                        while New_Len > File_Name_Buffer'Length loop
                           Double_File_Name_Buffer;
                        end loop;

                        File_Name_Buffer (Last + 1 + Offset .. New_Len) :=
                          File_Name_Buffer (Last + 1 .. Len);
                        Len := New_Len;
                        Last := Last + Offset;
                        File_Name_Buffer (First .. Last) :=
                          Name_Buffer (1 .. Name_Len);
                     end;
                  end if;

                  exit;
               end if;
            end loop;

            --  Skip over the symbol name or its value: we are not checking
            --  for another symbol name in the value.

            First := Last + 1;

         else
            First := First + 1;
         end if;
      end loop;

      --  We now have the output file name in the buffer. Get the output
      --  path and put it in Outfile_Name.

      Get_Name_String (Output_Directory);
      Add_Char_To_Name_Buffer (Directory_Separator);
      Add_Str_To_Name_Buffer (File_Name_Buffer (1 .. Len));
      Outfile_Name := Name_Find;
   end Preprocess_Infile_Name;

   --------------------------------------------
   -- Process_Command_Line_Symbol_Definition --
   --------------------------------------------

   procedure Process_Command_Line_Symbol_Definition (S : String) is
      Data   : Symbol_Data;
      Symbol : Symbol_Id;

   begin
      --  Check the symbol definition and get the symbol and its value.
      --  Fail if symbol definition is illegal.

      Check_Command_Line_Symbol_Definition (S, Data);

      Symbol := Index_Of (Data.Symbol);

      --  If symbol does not already exist, create a new entry in the mapping
      --  table.

      if Symbol = No_Symbol then
         Symbol_Table.Increment_Last (Mapping);
         Symbol := Symbol_Table.Last (Mapping);
      end if;

      Mapping.Table (Symbol) := Data;
   end Process_Command_Line_Symbol_Definition;

   -------------------
   -- Process_Files --
   -------------------

   procedure Process_Files is

      procedure Process_One_File;
      --  Process input file Infile_Name and put the result in file
      --  Outfile_Name.

      procedure Recursive_Process (In_Dir : String; Out_Dir : String);
      --  Process recursively files in In_Dir. Results go to Out_Dir

      ----------------------
      -- Process_One_File --
      ----------------------

      procedure Process_One_File is
         Infile : Source_File_Index;

         Modified : Boolean;
         pragma Warnings (Off, Modified);

      begin
         --  Create the output file (fails if this does not work)

         begin
            Create
              (File => Text_Outfile,
               Mode => Out_File,
               Name => Get_Name_String (Outfile_Name),
               Form => "Text_Translation=" &
                       Yes_No (Unix_Line_Terminators).all);

         exception
            when others =>
               Fail
                 ("unable to create output file """
                  & Get_Name_String (Outfile_Name)
                  & """");
         end;

         --  Load the input file

         Infile := Sinput.C.Load_File (Get_Name_String (Infile_Name));

         if Infile = No_Source_File then
            Fail ("unable to find input file """
                  & Get_Name_String (Infile_Name)
                  & """");
         end if;

         --  Set Main_Source_File to the input file for the benefit of
         --  Errutil.Finalize.

         Sinput.Main_Source_File := Infile;

         Scanner.Initialize_Scanner (Infile);

         --  Output the pragma Source_Reference if asked to

         if Source_Ref_Pragma then
            Put_Line
              (Outfile.all,
               "pragma Source_Reference (1, """ &
                 Get_Name_String (Sinput.Full_File_Name (Infile)) & """);");
         end if;

         --  Preprocess the input file

         Prep.Preprocess (Modified);

         --  In verbose mode, if there is no error, report it

         if Opt.Verbose_Mode and then Total_Errors_Detected = 0 then
            Errutil.Finalize (Source_Type => "input");
         end if;

         --  If we had some errors, delete the output file, and report them

         if Total_Errors_Detected > 0 then
            if Outfile /= Standard_Output then
               Delete (Text_Outfile);
            end if;

            Errutil.Finalize (Source_Type => "input");

            OS_Exit (0);

         --  Otherwise, close the output file, and we are done

         elsif Outfile /= Standard_Output then
            Close (Text_Outfile);
         end if;
      end Process_One_File;

      -----------------------
      -- Recursive_Process --
      -----------------------

      procedure Recursive_Process (In_Dir : String; Out_Dir : String) is
         Dir_In : Dir_Type;
         Name : String (1 .. 255);
         Last : Natural;
         In_Dir_Name  : Name_Id;
         Out_Dir_Name : Name_Id;

         procedure Set_Directory_Names;
         --  Establish or reestablish the current input and output directories

         -------------------------
         -- Set_Directory_Names --
         -------------------------

         procedure Set_Directory_Names is
         begin
            Input_Directory := In_Dir_Name;
            Output_Directory := Out_Dir_Name;
         end Set_Directory_Names;

      --  Start of processing for Recursive_Process

      begin
         --  Open the current input directory

         begin
            Open (Dir_In, In_Dir);

         exception
            when Directory_Error =>
               Fail ("could not read directory " & In_Dir);
         end;

         --  Set the new input and output directory names

         Name_Len := In_Dir'Length;
         Name_Buffer (1 .. Name_Len) := In_Dir;
         In_Dir_Name := Name_Find;
         Name_Len := Out_Dir'Length;
         Name_Buffer (1 .. Name_Len) := Out_Dir;
         Out_Dir_Name := Name_Find;

         Set_Directory_Names;

         --  Traverse the input directory
         loop
            Read (Dir_In, Name, Last);
            exit when Last = 0;

            if Name (1 .. Last) /= "." and then Name (1 .. Last) /= ".." then
               declare
                  Input : constant String :=
                            In_Dir & Directory_Separator & Name (1 .. Last);
                  Output : constant String :=
                             Out_Dir & Directory_Separator & Name (1 .. Last);

               begin
                  --  If input is an ordinary file, process it

                  if Is_Regular_File (Input) then
                     --  First get the output file name

                     Name_Len := Last;
                     Name_Buffer (1 .. Name_Len) := Name (1 .. Last);
                     Infile_Name := Name_Find;
                     Preprocess_Infile_Name;

                     --  Set the input file name and process the file

                     Name_Len := Input'Length;
                     Name_Buffer (1 .. Name_Len) := Input;
                     Infile_Name := Name_Find;
                     Process_One_File;

                  elsif Is_Directory (Input) then
                     --  Input is a directory. If the corresponding output
                     --  directory does not already exist, create it.

                     if not Is_Directory (Output) then
                        begin
                           Make_Dir (Dir_Name => Output);

                        exception
                           when Directory_Error =>
                              Fail ("could not create directory """
                                    & Output
                                    & """");
                        end;
                     end if;

                     --  And process this new input directory

                     Recursive_Process (Input, Output);

                     --  Reestablish the input and output directory names
                     --  that have been modified by the recursive call.

                     Set_Directory_Names;
                  end if;
               end;
            end if;
         end loop;
      end Recursive_Process;

   --  Start of processing for Process_Files

   begin
      if Output_Directory = No_Name then

         --  If the output is not a directory, fail if the input is
         --  an existing directory, to avoid possible problems.

         if Is_Directory (Get_Name_String (Infile_Name)) then
            Fail ("input file """ & Get_Name_String (Infile_Name) &
                  """ is a directory");
         end if;

         --  Just process the single input file

         Process_One_File;

      elsif Input_Directory = No_Name then

         --  Get the output file name from the input file name, and process
         --  the single input file.

         Preprocess_Infile_Name;
         Process_One_File;

      else
         --  Recursively process files in the directory tree rooted at the
         --  input directory.

         Recursive_Process
           (In_Dir => Get_Name_String (Input_Directory),
            Out_Dir => Get_Name_String (Output_Directory));
      end if;
   end Process_Files;

   -------------------------
   -- Put_Char_To_Outfile --
   -------------------------

   procedure Put_Char_To_Outfile (C : Character) is
   begin
      Put (Outfile.all, C);
   end Put_Char_To_Outfile;

   -----------------------
   -- Scan_Command_Line --
   -----------------------

   procedure Scan_Command_Line is
      Switch : Character;

      procedure Check_Version_And_Help is new Check_Version_And_Help_G (Usage);

      --  Start of processing for Scan_Command_Line

   begin
      --  First check for --version or --help

      Check_Version_And_Help ("GNATPREP", "1996");

      --  Now scan the other switches

      GNAT.Command_Line.Initialize_Option_Scan;

      loop
         begin
            Switch := GNAT.Command_Line.Getopt ("D: a b c C r s T u v");

            case Switch is

               when ASCII.NUL =>
                  exit;

               when 'D' =>
                  Process_Command_Line_Symbol_Definition
                    (S => GNAT.Command_Line.Parameter);

               when 'a' =>
                  Opt.No_Deletion := True;
                  Opt.Undefined_Symbols_Are_False := True;

               when 'b' =>
                  Opt.Blank_Deleted_Lines := True;

               when 'c' =>
                  Opt.Comment_Deleted_Lines := True;

               when 'C' =>
                  Opt.Replace_In_Comments := True;

               when 'r' =>
                  Source_Ref_Pragma := True;

               when 's' =>
                  Opt.List_Preprocessing_Symbols := True;

               when 'T' =>
                  Unix_Line_Terminators := True;

               when 'u' =>
                  Opt.Undefined_Symbols_Are_False := True;

               when 'v' =>
                  Opt.Verbose_Mode := True;

               when others =>
                  Fail ("Invalid Switch: -" & Switch);
            end case;

         exception
            when GNAT.Command_Line.Invalid_Switch =>
               Write_Str ("Invalid Switch: -");
               Write_Line (GNAT.Command_Line.Full_Switch);
               GNAT.Command_Line.Try_Help;
               OS_Exit (1);
         end;
      end loop;

      --  Get the file names

      loop
         declare
            S : constant String := GNAT.Command_Line.Get_Argument;

         begin
            exit when S'Length = 0;

            Name_Len := S'Length;
            Name_Buffer (1 .. Name_Len) := S;

            if Infile_Name = No_Name then
               Infile_Name := Name_Find;
            elsif Outfile_Name = No_Name then
               Outfile_Name := Name_Find;
            elsif Deffile_Name = No_Name then
               Deffile_Name := Name_Find;
            else
               Fail ("too many arguments specified");
            end if;
         end;
      end loop;
   end Scan_Command_Line;

   -----------
   -- Usage --
   -----------

   procedure Usage is
   begin
      Display_Copyright;
      Write_Line ("Usage: gnatprep [-bcrsuv] [-Dsymbol=value] " &
                    "infile outfile [deffile]");
      Write_Eol;
      Write_Line ("  infile     Name of the input file");
      Write_Line ("  outfile    Name of the output file");
      Write_Line ("  deffile    Name of the definition file");
      Write_Eol;
      Write_Line ("gnatprep switches:");
      Display_Usage_Version_And_Help;
      Write_Line ("   -b  Replace preprocessor lines by blank lines");
      Write_Line ("   -c  Keep preprocessor lines as comments");
      Write_Line ("   -C  Do symbol replacements within comments");
      Write_Line ("   -D  Associate symbol with value");
      Write_Line ("   -r  Generate Source_Reference pragma");
      Write_Line ("   -s  Print a sorted list of symbol names and values");
      Write_Line ("   -T  Use LF as line terminators");
      Write_Line ("   -u  Treat undefined symbols as FALSE");
      Write_Line ("   -v  Verbose mode");
      Write_Eol;
   end Usage;

end GPrep;