1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                          A D A . T E X T _ I O                           --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-2018, Free Software Foundation, Inc.         --
10--                                                                          --
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.                                     --
17--                                                                          --
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.               --
21--                                                                          --
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/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32with Ada.Streams;             use Ada.Streams;
33with Interfaces.C_Streams;    use Interfaces.C_Streams;
34
35with System.File_IO;
36with System.CRTL;
37with System.WCh_Cnv;          use System.WCh_Cnv;
38with System.WCh_Con;          use System.WCh_Con;
39
40with Ada.Unchecked_Conversion;
41with Ada.Unchecked_Deallocation;
42
43pragma Elaborate_All (System.File_IO);
44--  Needed because of calls to Chain_File in package body elaboration
45
46package body Ada.Text_IO is
47
48   package FIO renames System.File_IO;
49
50   subtype AP is FCB.AFCB_Ptr;
51
52   function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);
53   function To_TIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);
54   use type FCB.File_Mode;
55
56   use type System.CRTL.size_t;
57
58   WC_Encoding : Character;
59   pragma Import (C, WC_Encoding, "__gl_wc_encoding");
60   --  Default wide character encoding
61
62   Err_Name : aliased String := "*stderr" & ASCII.NUL;
63   In_Name  : aliased String := "*stdin" & ASCII.NUL;
64   Out_Name : aliased String := "*stdout" & ASCII.NUL;
65   --  Names of standard files
66   --
67   --  Use "preallocated" strings to avoid calling "new" during the elaboration
68   --  of the run time. This is needed in the tasking case to avoid calling
69   --  Task_Lock too early. A filename is expected to end with a null character
70   --  in the runtime, here the null characters are added just to have a
71   --  correct filename length.
72   --
73   --  Note: the names for these files are bogus, and probably it would be
74   --  better for these files to have no names, but the ACVC tests insist.
75   --  We use names that are bound to fail in open etc.
76
77   Null_Str : aliased constant String := "";
78   --  Used as form string for standard files
79
80   -----------------------
81   -- Local Subprograms --
82   -----------------------
83
84   function Get_Upper_Half_Char
85     (C    : Character;
86      File : File_Type) return Character;
87   --  This function is shared by Get and Get_Immediate to extract an encoded
88   --  upper half character value from the given File. The first byte has
89   --  already been read and is passed in C. The character value is returned as
90   --  the result, and the file pointer is bumped past the character.
91   --  Constraint_Error is raised if the encoded value is outside the bounds of
92   --  type Character.
93
94   function Get_Upper_Half_Char_Immed
95     (C    : Character;
96      File : File_Type) return Character;
97   --  This routine is identical to Get_Upper_Half_Char, except that the reads
98   --  are done in Get_Immediate mode (i.e. without waiting for a line return).
99
100   function Getc (File : File_Type) return int;
101   --  Gets next character from file, which has already been checked for being
102   --  in read status, and returns the character read if no error occurs. The
103   --  result is EOF if the end of file was read.
104
105   function Getc_Immed (File : File_Type) return int;
106   --  This routine is identical to Getc, except that the read is done in
107   --  Get_Immediate mode (i.e. without waiting for a line return).
108
109   function Has_Upper_Half_Character (Item : String) return Boolean;
110   --  Returns True if any of the characters is in the range 16#80#-16#FF#
111
112   function Nextc (File : File_Type) return int;
113   --  Returns next character from file without skipping past it (i.e. it is a
114   --  combination of Getc followed by an Ungetc).
115
116   procedure Put_Encoded (File : File_Type; Char : Character);
117   --  Called to output a character Char to the given File, when the encoding
118   --  method for the file is other than brackets, and Char is upper half.
119
120   procedure Putc (ch : int; File : File_Type);
121   --  Outputs the given character to the file, which has already been checked
122   --  for being in output status. Device_Error is raised if the character
123   --  cannot be written.
124
125   procedure Set_WCEM (File : in out File_Type);
126   --  Called by Open and Create to set the wide character encoding method for
127   --  the file, processing a WCEM form parameter if one is present. File is
128   --  IN OUT because it may be closed in case of an error.
129
130   procedure Terminate_Line (File : File_Type);
131   --  If the file is in Write_File or Append_File mode, and the current line
132   --  is not terminated, then a line terminator is written using New_Line.
133   --  Note that there is no Terminate_Page routine, because the page mark at
134   --  the end of the file is implied if necessary.
135
136   procedure Ungetc (ch : int; File : File_Type);
137   --  Pushes back character into stream, using ungetc. The caller has checked
138   --  that the file is in read status. Device_Error is raised if the character
139   --  cannot be pushed back. An attempt to push back and end of file character
140   --  (EOF) is ignored.
141
142   -------------------
143   -- AFCB_Allocate --
144   -------------------
145
146   function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr is
147      pragma Unreferenced (Control_Block);
148   begin
149      return new Text_AFCB;
150   end AFCB_Allocate;
151
152   ----------------
153   -- AFCB_Close --
154   ----------------
155
156   procedure AFCB_Close (File : not null access Text_AFCB) is
157   begin
158      --  If the file being closed is one of the current files, then close
159      --  the corresponding current file. It is not clear that this action
160      --  is required (RM A.10.3(23)) but it seems reasonable, and besides
161      --  ACVC test CE3208A expects this behavior.
162
163      if File_Type (File) = Current_In then
164         Current_In := null;
165      elsif File_Type (File) = Current_Out then
166         Current_Out := null;
167      elsif File_Type (File) = Current_Err then
168         Current_Err := null;
169      end if;
170
171      Terminate_Line (File_Type (File));
172   end AFCB_Close;
173
174   ---------------
175   -- AFCB_Free --
176   ---------------
177
178   procedure AFCB_Free (File : not null access Text_AFCB) is
179      type FCB_Ptr is access all Text_AFCB;
180      FT : FCB_Ptr := FCB_Ptr (File);
181
182      procedure Free is new Ada.Unchecked_Deallocation (Text_AFCB, FCB_Ptr);
183
184   begin
185      Free (FT);
186   end AFCB_Free;
187
188   -----------
189   -- Close --
190   -----------
191
192   procedure Close (File : in out File_Type) is
193   begin
194      FIO.Close (AP (File)'Unrestricted_Access);
195   end Close;
196
197   ---------
198   -- Col --
199   ---------
200
201   --  Note: we assume that it is impossible in practice for the column
202   --  to exceed the value of Count'Last, i.e. no check is required for
203   --  overflow raising layout error.
204
205   function Col (File : File_Type) return Positive_Count is
206   begin
207      FIO.Check_File_Open (AP (File));
208      return File.Col;
209   end Col;
210
211   function Col return Positive_Count is
212   begin
213      return Col (Current_Out);
214   end Col;
215
216   ------------
217   -- Create --
218   ------------
219
220   procedure Create
221     (File : in out File_Type;
222      Mode : File_Mode := Out_File;
223      Name : String := "";
224      Form : String := "")
225   is
226      Dummy_File_Control_Block : Text_AFCB;
227      pragma Warnings (Off, Dummy_File_Control_Block);
228      --  Yes, we know this is never assigned a value, only the tag
229      --  is used for dispatching purposes, so that's expected.
230
231   begin
232      FIO.Open (File_Ptr  => AP (File),
233                Dummy_FCB => Dummy_File_Control_Block,
234                Mode      => To_FCB (Mode),
235                Name      => Name,
236                Form      => Form,
237                Amethod   => 'T',
238                Creat     => True,
239                Text      => True);
240
241      File.Self := File;
242      Set_WCEM (File);
243   end Create;
244
245   -------------------
246   -- Current_Error --
247   -------------------
248
249   function Current_Error return File_Type is
250   begin
251      return Current_Err;
252   end Current_Error;
253
254   function Current_Error return File_Access is
255   begin
256      return Current_Err.Self'Access;
257   end Current_Error;
258
259   -------------------
260   -- Current_Input --
261   -------------------
262
263   function Current_Input return File_Type is
264   begin
265      return Current_In;
266   end Current_Input;
267
268   function Current_Input return File_Access is
269   begin
270      return Current_In.Self'Access;
271   end Current_Input;
272
273   --------------------
274   -- Current_Output --
275   --------------------
276
277   function Current_Output return File_Type is
278   begin
279      return Current_Out;
280   end Current_Output;
281
282   function Current_Output return File_Access is
283   begin
284      return Current_Out.Self'Access;
285   end Current_Output;
286
287   ------------
288   -- Delete --
289   ------------
290
291   procedure Delete (File : in out File_Type) is
292   begin
293      FIO.Delete (AP (File)'Unrestricted_Access);
294   end Delete;
295
296   -----------------
297   -- End_Of_File --
298   -----------------
299
300   function End_Of_File (File : File_Type) return Boolean is
301      ch : int;
302
303   begin
304      FIO.Check_Read_Status (AP (File));
305
306      if File.Before_Upper_Half_Character then
307         return False;
308
309      elsif File.Before_LM then
310         if File.Before_LM_PM then
311            return Nextc (File) = EOF;
312         end if;
313
314      else
315         ch := Getc (File);
316
317         if ch = EOF then
318            return True;
319
320         elsif ch /= LM then
321            Ungetc (ch, File);
322            return False;
323
324         else -- ch = LM
325            File.Before_LM := True;
326         end if;
327      end if;
328
329      --  Here we are just past the line mark with Before_LM set so that we
330      --  do not have to try to back up past the LM, thus avoiding the need
331      --  to back up more than one character.
332
333      ch := Getc (File);
334
335      if ch = EOF then
336         return True;
337
338      elsif ch = PM and then File.Is_Regular_File then
339         File.Before_LM_PM := True;
340         return Nextc (File) = EOF;
341
342      --  Here if neither EOF nor PM followed end of line
343
344      else
345         Ungetc (ch, File);
346         return False;
347      end if;
348
349   end End_Of_File;
350
351   function End_Of_File return Boolean is
352   begin
353      return End_Of_File (Current_In);
354   end End_Of_File;
355
356   -----------------
357   -- End_Of_Line --
358   -----------------
359
360   function End_Of_Line (File : File_Type) return Boolean is
361      ch : int;
362
363   begin
364      FIO.Check_Read_Status (AP (File));
365
366      if File.Before_Upper_Half_Character then
367         return False;
368
369      elsif File.Before_LM then
370         return True;
371
372      else
373         ch := Getc (File);
374
375         if ch = EOF then
376            return True;
377
378         else
379            Ungetc (ch, File);
380            return (ch = LM);
381         end if;
382      end if;
383   end End_Of_Line;
384
385   function End_Of_Line return Boolean is
386   begin
387      return End_Of_Line (Current_In);
388   end End_Of_Line;
389
390   -----------------
391   -- End_Of_Page --
392   -----------------
393
394   function End_Of_Page (File : File_Type) return Boolean is
395      ch  : int;
396
397   begin
398      FIO.Check_Read_Status (AP (File));
399
400      if not File.Is_Regular_File then
401         return False;
402
403      elsif File.Before_Upper_Half_Character then
404         return False;
405
406      elsif File.Before_LM then
407         if File.Before_LM_PM then
408            return True;
409         end if;
410
411      else
412         ch := Getc (File);
413
414         if ch = EOF then
415            return True;
416
417         elsif ch /= LM then
418            Ungetc (ch, File);
419            return False;
420
421         else -- ch = LM
422            File.Before_LM := True;
423         end if;
424      end if;
425
426      --  Here we are just past the line mark with Before_LM set so that we
427      --  do not have to try to back up past the LM, thus avoiding the need
428      --  to back up more than one character.
429
430      ch := Nextc (File);
431
432      return ch = PM or else ch = EOF;
433   end End_Of_Page;
434
435   function End_Of_Page return Boolean is
436   begin
437      return End_Of_Page (Current_In);
438   end End_Of_Page;
439
440   --------------
441   -- EOF_Char --
442   --------------
443
444   function EOF_Char return Integer is
445   begin
446      return EOF;
447   end EOF_Char;
448
449   -----------
450   -- Flush --
451   -----------
452
453   procedure Flush (File : File_Type) is
454   begin
455      FIO.Flush (AP (File));
456   end Flush;
457
458   procedure Flush is
459   begin
460      Flush (Current_Out);
461   end Flush;
462
463   ----------
464   -- Form --
465   ----------
466
467   function Form (File : File_Type) return String is
468   begin
469      return FIO.Form (AP (File));
470   end Form;
471
472   ---------
473   -- Get --
474   ---------
475
476   procedure Get
477     (File : File_Type;
478      Item : out Character)
479   is
480      ch : int;
481
482   begin
483      FIO.Check_Read_Status (AP (File));
484
485      if File.Before_Upper_Half_Character then
486         File.Before_Upper_Half_Character := False;
487         Item := File.Saved_Upper_Half_Character;
488
489      elsif File.Before_LM then
490         File.Before_LM := False;
491         File.Col := 1;
492
493         if File.Before_LM_PM then
494            File.Line := 1;
495            File.Page := File.Page + 1;
496            File.Before_LM_PM := False;
497         else
498            File.Line := File.Line + 1;
499         end if;
500      end if;
501
502      loop
503         ch := Getc (File);
504
505         if ch = EOF then
506            raise End_Error;
507
508         elsif ch = LM then
509            File.Line := File.Line + 1;
510            File.Col := 1;
511
512         elsif ch = PM and then File.Is_Regular_File then
513            File.Page := File.Page + 1;
514            File.Line := 1;
515
516         else
517            Item := Character'Val (ch);
518            File.Col := File.Col + 1;
519            return;
520         end if;
521      end loop;
522   end Get;
523
524   procedure Get (Item : out Character) is
525   begin
526      Get (Current_In, Item);
527   end Get;
528
529   procedure Get
530     (File : File_Type;
531      Item : out String)
532   is
533      ch : int;
534      J  : Natural;
535
536   begin
537      FIO.Check_Read_Status (AP (File));
538
539      if File.Before_LM then
540         File.Before_LM := False;
541         File.Before_LM_PM := False;
542         File.Col := 1;
543
544         if File.Before_LM_PM then
545            File.Line := 1;
546            File.Page := File.Page + 1;
547            File.Before_LM_PM := False;
548
549         else
550            File.Line := File.Line + 1;
551         end if;
552      end if;
553
554      J := Item'First;
555      while J <= Item'Last loop
556         ch := Getc (File);
557
558         if ch = EOF then
559            raise End_Error;
560
561         elsif ch = LM then
562            File.Line := File.Line + 1;
563            File.Col := 1;
564
565         elsif ch = PM and then File.Is_Regular_File then
566            File.Page := File.Page + 1;
567            File.Line := 1;
568
569         else
570            Item (J) := Character'Val (ch);
571            J := J + 1;
572            File.Col := File.Col + 1;
573         end if;
574      end loop;
575   end Get;
576
577   procedure Get (Item : out String) is
578   begin
579      Get (Current_In, Item);
580   end Get;
581
582   -------------------
583   -- Get_Immediate --
584   -------------------
585
586   procedure Get_Immediate
587     (File : File_Type;
588      Item : out Character)
589   is
590      ch          : int;
591
592   begin
593      FIO.Check_Read_Status (AP (File));
594
595      if File.Before_Upper_Half_Character then
596         File.Before_Upper_Half_Character := False;
597         Item := File.Saved_Upper_Half_Character;
598
599      elsif File.Before_LM then
600         File.Before_LM := False;
601         File.Before_LM_PM := False;
602         Item := Character'Val (LM);
603
604      else
605         ch := Getc_Immed (File);
606
607         if ch = EOF then
608            raise End_Error;
609         else
610            Item :=
611              (if not Is_Start_Of_Encoding (Character'Val (ch), File.WC_Method)
612               then Character'Val (ch)
613               else Get_Upper_Half_Char_Immed (Character'Val (ch), File));
614         end if;
615      end if;
616   end Get_Immediate;
617
618   procedure Get_Immediate
619     (Item : out Character)
620   is
621   begin
622      Get_Immediate (Current_In, Item);
623   end Get_Immediate;
624
625   procedure Get_Immediate
626     (File      : File_Type;
627      Item      : out Character;
628      Available : out Boolean)
629   is
630      ch          : int;
631      end_of_file : int;
632      avail       : int;
633
634      procedure getc_immediate_nowait
635        (stream      : FILEs;
636         ch          : out int;
637         end_of_file : out int;
638         avail       : out int);
639      pragma Import (C, getc_immediate_nowait, "getc_immediate_nowait");
640
641   begin
642      FIO.Check_Read_Status (AP (File));
643      Available := True;
644
645      if File.Before_Upper_Half_Character then
646         File.Before_Upper_Half_Character := False;
647         Item := File.Saved_Upper_Half_Character;
648
649      elsif File.Before_LM then
650         File.Before_LM := False;
651         File.Before_LM_PM := False;
652         Item := Character'Val (LM);
653
654      else
655         getc_immediate_nowait (File.Stream, ch, end_of_file, avail);
656
657         if ferror (File.Stream) /= 0 then
658            raise Device_Error;
659
660         elsif end_of_file /= 0 then
661            raise End_Error;
662
663         elsif avail = 0 then
664            Available := False;
665            Item := ASCII.NUL;
666
667         else
668            Available := True;
669
670            Item :=
671              (if not Is_Start_Of_Encoding (Character'Val (ch), File.WC_Method)
672               then Character'Val (ch)
673               else Get_Upper_Half_Char_Immed (Character'Val (ch), File));
674         end if;
675      end if;
676
677   end Get_Immediate;
678
679   procedure Get_Immediate
680     (Item      : out Character;
681      Available : out Boolean)
682   is
683   begin
684      Get_Immediate (Current_In, Item, Available);
685   end Get_Immediate;
686
687   --------------
688   -- Get_Line --
689   --------------
690
691   procedure Get_Line
692     (File : File_Type;
693      Item : out String;
694      Last : out Natural) is separate;
695   --  The implementation of Ada.Text_IO.Get_Line is split into a subunit so
696   --  that different implementations can be used on different systems.
697
698   procedure Get_Line
699     (Item : out String;
700      Last : out Natural)
701   is
702   begin
703      Get_Line (Current_In, Item, Last);
704   end Get_Line;
705
706   function Get_Line (File : File_Type) return String is
707      function Get_Rest (S : String) return String;
708      --  This is a recursive function that reads the rest of the line and
709      --  returns it. S is the part read so far.
710
711      --------------
712      -- Get_Rest --
713      --------------
714
715      function Get_Rest (S : String) return String is
716
717         --  The first time we allocate a buffer of size 500. Each following
718         --  time we allocate a buffer the same size as what we have read so
719         --  far. This limits us to a logarithmic number of calls to Get_Rest
720         --  and also ensures only a linear use of stack space.
721
722         Buffer : String (1 .. Integer'Max (500, S'Length));
723         Last   : Natural;
724
725      begin
726         Get_Line (File, Buffer, Last);
727
728         declare
729            R : constant String := S & Buffer (1 .. Last);
730         begin
731            if Last < Buffer'Last then
732               return R;
733
734            else
735               pragma Assert (Last = Buffer'Last);
736
737               --  If the String has the same length as the buffer, and there
738               --  is no end of line, check whether we are at the end of file,
739               --  in which case we have the full String in the buffer.
740
741               if End_Of_File (File) then
742                  return R;
743
744               else
745                  return Get_Rest (R);
746               end if;
747            end if;
748         end;
749      end Get_Rest;
750
751   --  Start of processing for Get_Line
752
753   begin
754      return Get_Rest ("");
755   end Get_Line;
756
757   function Get_Line return String is
758   begin
759      return Get_Line (Current_In);
760   end Get_Line;
761
762   -------------------------
763   -- Get_Upper_Half_Char --
764   -------------------------
765
766   function Get_Upper_Half_Char
767     (C    : Character;
768      File : File_Type) return Character
769   is
770      Result : Wide_Character;
771
772      function In_Char return Character;
773      --  Function used to obtain additional characters it the wide character
774      --  sequence is more than one character long.
775
776      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
777
778      -------------
779      -- In_Char --
780      -------------
781
782      function In_Char return Character is
783         ch : constant Integer := Getc (File);
784      begin
785         if ch = EOF then
786            raise End_Error;
787         else
788            return Character'Val (ch);
789         end if;
790      end In_Char;
791
792   --  Start of processing for Get_Upper_Half_Char
793
794   begin
795      Result := WC_In (C, File.WC_Method);
796
797      if Wide_Character'Pos (Result) > 16#FF# then
798         raise Constraint_Error with
799           "invalid wide character in Text_'I'O input";
800      else
801         return Character'Val (Wide_Character'Pos (Result));
802      end if;
803   end Get_Upper_Half_Char;
804
805   -------------------------------
806   -- Get_Upper_Half_Char_Immed --
807   -------------------------------
808
809   function Get_Upper_Half_Char_Immed
810     (C    : Character;
811      File : File_Type) return Character
812   is
813      Result : Wide_Character;
814
815      function In_Char return Character;
816      --  Function used to obtain additional characters it the wide character
817      --  sequence is more than one character long.
818
819      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
820
821      -------------
822      -- In_Char --
823      -------------
824
825      function In_Char return Character is
826         ch : constant Integer := Getc_Immed (File);
827      begin
828         if ch = EOF then
829            raise End_Error;
830         else
831            return Character'Val (ch);
832         end if;
833      end In_Char;
834
835   --  Start of processing for Get_Upper_Half_Char_Immed
836
837   begin
838      Result := WC_In (C, File.WC_Method);
839
840      if Wide_Character'Pos (Result) > 16#FF# then
841         raise Constraint_Error with
842           "invalid wide character in Text_'I'O input";
843      else
844         return Character'Val (Wide_Character'Pos (Result));
845      end if;
846   end Get_Upper_Half_Char_Immed;
847
848   ----------
849   -- Getc --
850   ----------
851
852   function Getc (File : File_Type) return int is
853      ch : int;
854
855   begin
856      ch := fgetc (File.Stream);
857
858      if ch = EOF and then ferror (File.Stream) /= 0 then
859         raise Device_Error;
860      else
861         return ch;
862      end if;
863   end Getc;
864
865   ----------------
866   -- Getc_Immed --
867   ----------------
868
869   function Getc_Immed (File : File_Type) return int is
870      ch          : int;
871      end_of_file : int;
872
873      procedure getc_immediate
874        (stream : FILEs; ch : out int; end_of_file : out int);
875      pragma Import (C, getc_immediate, "getc_immediate");
876
877   begin
878      FIO.Check_Read_Status (AP (File));
879
880      if File.Before_LM then
881         File.Before_LM := False;
882         File.Before_LM_PM := False;
883         ch := LM;
884
885      else
886         getc_immediate (File.Stream, ch, end_of_file);
887
888         if ferror (File.Stream) /= 0 then
889            raise Device_Error;
890         elsif end_of_file /= 0 then
891            return EOF;
892         end if;
893      end if;
894
895      return ch;
896   end Getc_Immed;
897
898   ------------------------------
899   -- Has_Upper_Half_Character --
900   ------------------------------
901
902   function Has_Upper_Half_Character (Item : String) return Boolean is
903   begin
904      for J in Item'Range loop
905         if Character'Pos (Item (J)) >= 16#80# then
906            return True;
907         end if;
908      end loop;
909
910      return False;
911   end Has_Upper_Half_Character;
912
913   -------------------------------
914   -- Initialize_Standard_Files --
915   -------------------------------
916
917   procedure Initialize_Standard_Files is
918   begin
919      Standard_Err.Stream            := stderr;
920      Standard_Err.Name              := Err_Name'Access;
921      Standard_Err.Form              := Null_Str'Unrestricted_Access;
922      Standard_Err.Mode              := FCB.Out_File;
923      Standard_Err.Is_Regular_File   := is_regular_file (fileno (stderr)) /= 0;
924      Standard_Err.Is_Temporary_File := False;
925      Standard_Err.Is_System_File    := True;
926      Standard_Err.Text_Encoding     := Default_Text;
927      Standard_Err.Access_Method     := 'T';
928      Standard_Err.Self              := Standard_Err;
929      Standard_Err.WC_Method         := Default_WCEM;
930
931      Standard_In.Stream             := stdin;
932      Standard_In.Name               := In_Name'Access;
933      Standard_In.Form               := Null_Str'Unrestricted_Access;
934      Standard_In.Mode               := FCB.In_File;
935      Standard_In.Is_Regular_File    := is_regular_file (fileno (stdin)) /= 0;
936      Standard_In.Is_Temporary_File  := False;
937      Standard_In.Is_System_File     := True;
938      Standard_In.Text_Encoding      := Default_Text;
939      Standard_In.Access_Method      := 'T';
940      Standard_In.Self               := Standard_In;
941      Standard_In.WC_Method          := Default_WCEM;
942
943      Standard_Out.Stream            := stdout;
944      Standard_Out.Name              := Out_Name'Access;
945      Standard_Out.Form              := Null_Str'Unrestricted_Access;
946      Standard_Out.Mode              := FCB.Out_File;
947      Standard_Out.Is_Regular_File   := is_regular_file (fileno (stdout)) /= 0;
948      Standard_Out.Is_Temporary_File := False;
949      Standard_Out.Is_System_File    := True;
950      Standard_Out.Text_Encoding     := Default_Text;
951      Standard_Out.Access_Method     := 'T';
952      Standard_Out.Self              := Standard_Out;
953      Standard_Out.WC_Method         := Default_WCEM;
954
955      FIO.Make_Unbuffered (AP (Standard_Out));
956      FIO.Make_Unbuffered (AP (Standard_Err));
957   end Initialize_Standard_Files;
958
959   -------------
960   -- Is_Open --
961   -------------
962
963   function Is_Open (File : File_Type) return Boolean is
964   begin
965      return FIO.Is_Open (AP (File));
966   end Is_Open;
967
968   ----------
969   -- Line --
970   ----------
971
972   --  Note: we assume that it is impossible in practice for the line
973   --  to exceed the value of Count'Last, i.e. no check is required for
974   --  overflow raising layout error.
975
976   function Line (File : File_Type) return Positive_Count is
977   begin
978      FIO.Check_File_Open (AP (File));
979      return File.Line;
980   end Line;
981
982   function Line return Positive_Count is
983   begin
984      return Line (Current_Out);
985   end Line;
986
987   -----------------
988   -- Line_Length --
989   -----------------
990
991   function Line_Length (File : File_Type) return Count is
992   begin
993      FIO.Check_Write_Status (AP (File));
994      return File.Line_Length;
995   end Line_Length;
996
997   function Line_Length return Count is
998   begin
999      return Line_Length (Current_Out);
1000   end Line_Length;
1001
1002   ----------------
1003   -- Look_Ahead --
1004   ----------------
1005
1006   procedure Look_Ahead
1007     (File        : File_Type;
1008      Item        : out Character;
1009      End_Of_Line : out Boolean)
1010   is
1011      ch : int;
1012
1013   begin
1014      FIO.Check_Read_Status (AP (File));
1015
1016      --  If we are logically before a line mark, we can return immediately
1017
1018      if File.Before_LM then
1019         End_Of_Line := True;
1020         Item := ASCII.NUL;
1021
1022      --  If we are before an upper half character just return it (this can
1023      --  happen if there are two calls to Look_Ahead in a row).
1024
1025      elsif File.Before_Upper_Half_Character then
1026         End_Of_Line := False;
1027         Item := File.Saved_Upper_Half_Character;
1028
1029      --  Otherwise we must read a character from the input stream
1030
1031      else
1032         ch := Getc (File);
1033
1034         if ch = LM
1035           or else ch = EOF
1036           or else (ch = PM and then File.Is_Regular_File)
1037         then
1038            End_Of_Line := True;
1039            Ungetc (ch, File);
1040            Item := ASCII.NUL;
1041
1042         --  Case where character obtained does not represent the start of an
1043         --  encoded sequence so it stands for itself and we can unget it with
1044         --  no difficulty.
1045
1046         elsif not Is_Start_Of_Encoding
1047                     (Character'Val (ch), File.WC_Method)
1048         then
1049            End_Of_Line := False;
1050            Ungetc (ch, File);
1051            Item := Character'Val (ch);
1052
1053         --  For the start of an encoding, we read the character using the
1054         --  Get_Upper_Half_Char routine. It will occupy more than one byte
1055         --  so we can't put it back with ungetc. Instead we save it in the
1056         --  control block, setting a flag that everyone interested in reading
1057         --  characters must test before reading the stream.
1058
1059         else
1060            Item := Get_Upper_Half_Char (Character'Val (ch), File);
1061            End_Of_Line := False;
1062            File.Saved_Upper_Half_Character := Item;
1063            File.Before_Upper_Half_Character := True;
1064         end if;
1065      end if;
1066   end Look_Ahead;
1067
1068   procedure Look_Ahead
1069     (Item        : out Character;
1070      End_Of_Line : out Boolean)
1071   is
1072   begin
1073      Look_Ahead (Current_In, Item, End_Of_Line);
1074   end Look_Ahead;
1075
1076   ----------
1077   -- Mode --
1078   ----------
1079
1080   function Mode (File : File_Type) return File_Mode is
1081   begin
1082      return To_TIO (FIO.Mode (AP (File)));
1083   end Mode;
1084
1085   ----------
1086   -- Name --
1087   ----------
1088
1089   function Name (File : File_Type) return String is
1090   begin
1091      return FIO.Name (AP (File));
1092   end Name;
1093
1094   --------------
1095   -- New_Line --
1096   --------------
1097
1098   procedure New_Line
1099     (File    : File_Type;
1100      Spacing : Positive_Count := 1)
1101   is
1102   begin
1103      --  Raise Constraint_Error if out of range value. The reason for this
1104      --  explicit test is that we don't want junk values around, even if
1105      --  checks are off in the caller.
1106
1107      if not Spacing'Valid then
1108         raise Constraint_Error;
1109      end if;
1110
1111      FIO.Check_Write_Status (AP (File));
1112
1113      for K in 1 .. Spacing loop
1114         Putc (LM, File);
1115         File.Line := File.Line + 1;
1116
1117         if File.Page_Length /= 0
1118           and then File.Line > File.Page_Length
1119         then
1120            Putc (PM, File);
1121            File.Line := 1;
1122            File.Page := File.Page + 1;
1123         end if;
1124      end loop;
1125
1126      File.Col := 1;
1127   end New_Line;
1128
1129   procedure New_Line (Spacing : Positive_Count := 1) is
1130   begin
1131      New_Line (Current_Out, Spacing);
1132   end New_Line;
1133
1134   --------------
1135   -- New_Page --
1136   --------------
1137
1138   procedure New_Page (File : File_Type) is
1139   begin
1140      FIO.Check_Write_Status (AP (File));
1141
1142      if File.Col /= 1 or else File.Line = 1 then
1143         Putc (LM, File);
1144      end if;
1145
1146      Putc (PM, File);
1147      File.Page := File.Page + 1;
1148      File.Line := 1;
1149      File.Col := 1;
1150   end New_Page;
1151
1152   procedure New_Page is
1153   begin
1154      New_Page (Current_Out);
1155   end New_Page;
1156
1157   -----------
1158   -- Nextc --
1159   -----------
1160
1161   function Nextc (File : File_Type) return int is
1162      ch : int;
1163
1164   begin
1165      ch := fgetc (File.Stream);
1166
1167      if ch = EOF then
1168         if ferror (File.Stream) /= 0 then
1169            raise Device_Error;
1170         end if;
1171
1172      else
1173         if ungetc (ch, File.Stream) = EOF then
1174            raise Device_Error;
1175         end if;
1176      end if;
1177
1178      return ch;
1179   end Nextc;
1180
1181   ----------
1182   -- Open --
1183   ----------
1184
1185   procedure Open
1186     (File : in out File_Type;
1187      Mode : File_Mode;
1188      Name : String;
1189      Form : String := "")
1190   is
1191      Dummy_File_Control_Block : Text_AFCB;
1192      pragma Warnings (Off, Dummy_File_Control_Block);
1193      --  Yes, we know this is never assigned a value, only the tag
1194      --  is used for dispatching purposes, so that's expected.
1195
1196   begin
1197      FIO.Open (File_Ptr  => AP (File),
1198                Dummy_FCB => Dummy_File_Control_Block,
1199                Mode      => To_FCB (Mode),
1200                Name      => Name,
1201                Form      => Form,
1202                Amethod   => 'T',
1203                Creat     => False,
1204                Text      => True);
1205
1206      File.Self := File;
1207      Set_WCEM (File);
1208   end Open;
1209
1210   ----------
1211   -- Page --
1212   ----------
1213
1214   --  Note: we assume that it is impossible in practice for the page
1215   --  to exceed the value of Count'Last, i.e. no check is required for
1216   --  overflow raising layout error.
1217
1218   function Page (File : File_Type) return Positive_Count is
1219   begin
1220      FIO.Check_File_Open (AP (File));
1221      return File.Page;
1222   end Page;
1223
1224   function Page return Positive_Count is
1225   begin
1226      return Page (Current_Out);
1227   end Page;
1228
1229   -----------------
1230   -- Page_Length --
1231   -----------------
1232
1233   function Page_Length (File : File_Type) return Count is
1234   begin
1235      FIO.Check_Write_Status (AP (File));
1236      return File.Page_Length;
1237   end Page_Length;
1238
1239   function Page_Length return Count is
1240   begin
1241      return Page_Length (Current_Out);
1242   end Page_Length;
1243
1244   ---------
1245   -- Put --
1246   ---------
1247
1248   procedure Put
1249     (File : File_Type;
1250      Item : Character)
1251   is
1252   begin
1253      FIO.Check_Write_Status (AP (File));
1254
1255      if File.Line_Length /= 0 and then File.Col > File.Line_Length then
1256         New_Line (File);
1257      end if;
1258
1259      --  If lower half character, or brackets encoding, output directly
1260
1261      if Character'Pos (Item) < 16#80#
1262        or else File.WC_Method = WCEM_Brackets
1263      then
1264         if fputc (Character'Pos (Item), File.Stream) = EOF then
1265            raise Device_Error;
1266         end if;
1267
1268      --  Case of upper half character with non-brackets encoding
1269
1270      else
1271         Put_Encoded (File, Item);
1272      end if;
1273
1274      File.Col := File.Col + 1;
1275   end Put;
1276
1277   procedure Put (Item : Character) is
1278   begin
1279      Put (Current_Out, Item);
1280   end Put;
1281
1282   ---------
1283   -- Put --
1284   ---------
1285
1286   procedure Put
1287     (File : File_Type;
1288      Item : String)
1289   is
1290   begin
1291      FIO.Check_Write_Status (AP (File));
1292
1293      --  Only have something to do if string is non-null
1294
1295      if Item'Length > 0 then
1296
1297         --  If we have bounded lines, or if the file encoding is other than
1298         --  Brackets and the string has at least one upper half character,
1299         --  then output the string character by character.
1300
1301         if File.Line_Length /= 0
1302           or else (File.WC_Method /= WCEM_Brackets
1303                      and then Has_Upper_Half_Character (Item))
1304         then
1305            for J in Item'Range loop
1306               Put (File, Item (J));
1307            end loop;
1308
1309         --  Otherwise we can output the entire string at once. Note that if
1310         --  there are LF or FF characters in the string, we do not bother to
1311         --  count them as line or page terminators.
1312
1313         else
1314            FIO.Write_Buf (AP (File), Item'Address, Item'Length);
1315            File.Col := File.Col + Item'Length;
1316         end if;
1317      end if;
1318   end Put;
1319
1320   procedure Put (Item : String) is
1321   begin
1322      Put (Current_Out, Item);
1323   end Put;
1324
1325   -----------------
1326   -- Put_Encoded --
1327   -----------------
1328
1329   procedure Put_Encoded (File : File_Type; Char : Character) is
1330      procedure Out_Char (C : Character);
1331      --  Procedure to output one character of an upper half encoded sequence
1332
1333      procedure WC_Out is new Wide_Char_To_Char_Sequence (Out_Char);
1334
1335      --------------
1336      -- Out_Char --
1337      --------------
1338
1339      procedure Out_Char (C : Character) is
1340      begin
1341         Putc (Character'Pos (C), File);
1342      end Out_Char;
1343
1344   --  Start of processing for Put_Encoded
1345
1346   begin
1347      WC_Out (Wide_Character'Val (Character'Pos (Char)), File.WC_Method);
1348   end Put_Encoded;
1349
1350   --------------
1351   -- Put_Line --
1352   --------------
1353
1354   procedure Put_Line
1355     (File : File_Type;
1356      Item : String)
1357   is
1358      Ilen   : Natural := Item'Length;
1359      Istart : Natural := Item'First;
1360
1361   begin
1362      FIO.Check_Write_Status (AP (File));
1363
1364      --  If we have bounded lines, or if the file encoding is other than
1365      --  Brackets and the string has at least one upper half character, then
1366      --  output the string character by character.
1367
1368      if File.Line_Length /= 0
1369        or else (File.WC_Method /= WCEM_Brackets
1370                   and then Has_Upper_Half_Character (Item))
1371      then
1372         for J in Item'Range loop
1373            Put (File, Item (J));
1374         end loop;
1375
1376         New_Line (File);
1377         return;
1378      end if;
1379
1380      --  Normal case where we do not need to output character by character
1381
1382      --  We setup a single string that has the necessary terminators and
1383      --  then write it with a single call. The reason for doing this is
1384      --  that it gives better behavior for the use of Put_Line in multi-
1385      --  tasking programs, since often the OS will treat the entire put
1386      --  operation as an atomic operation.
1387
1388      --  We only do this if the message is 512 characters or less in length,
1389      --  since otherwise Put_Line would use an unbounded amount of stack
1390      --  space and could cause undetected stack overflow. If we have a
1391      --  longer string, then output the first part separately to avoid this.
1392
1393      if Ilen > 512 then
1394         FIO.Write_Buf (AP (File), Item'Address, size_t (Ilen - 512));
1395         Istart := Istart + Ilen - 512;
1396         Ilen   := 512;
1397      end if;
1398
1399      --  Now prepare the string with its terminator
1400
1401      declare
1402         Buffer : String (1 .. Ilen + 2);
1403         Plen   : size_t;
1404
1405      begin
1406         Buffer (1 .. Ilen) := Item (Istart .. Item'Last);
1407         Buffer (Ilen + 1) := Character'Val (LM);
1408
1409         if File.Page_Length /= 0
1410           and then File.Line > File.Page_Length
1411         then
1412            Buffer (Ilen + 2) := Character'Val (PM);
1413            Plen := size_t (Ilen) + 2;
1414            File.Line := 1;
1415            File.Page := File.Page + 1;
1416
1417         else
1418            Plen := size_t (Ilen) + 1;
1419            File.Line := File.Line + 1;
1420         end if;
1421
1422         FIO.Write_Buf (AP (File), Buffer'Address, Plen);
1423
1424         File.Col := 1;
1425      end;
1426   end Put_Line;
1427
1428   procedure Put_Line (Item : String) is
1429   begin
1430      Put_Line (Current_Out, Item);
1431   end Put_Line;
1432
1433   ----------
1434   -- Putc --
1435   ----------
1436
1437   procedure Putc (ch : int; File : File_Type) is
1438   begin
1439      if fputc (ch, File.Stream) = EOF then
1440         raise Device_Error;
1441      end if;
1442   end Putc;
1443
1444   ----------
1445   -- Read --
1446   ----------
1447
1448   --  This is the primitive Stream Read routine, used when a Text_IO file
1449   --  is treated directly as a stream using Text_IO.Streams.Stream.
1450
1451   procedure Read
1452     (File : in out Text_AFCB;
1453      Item : out Stream_Element_Array;
1454      Last : out Stream_Element_Offset)
1455   is
1456      Discard_ch : int;
1457      pragma Warnings (Off, Discard_ch);
1458
1459   begin
1460      --  Need to deal with Before_Upper_Half_Character ???
1461
1462      if File.Mode /= FCB.In_File then
1463         raise Mode_Error;
1464      end if;
1465
1466      --  Deal with case where our logical and physical position do not match
1467      --  because of being after an LM or LM-PM sequence when in fact we are
1468      --  logically positioned before it.
1469
1470      if File.Before_LM then
1471
1472         --  If we are before a PM, then it is possible for a stream read
1473         --  to leave us after the LM and before the PM, which is a bit
1474         --  odd. The easiest way to deal with this is to unget the PM,
1475         --  so we are indeed positioned between the characters. This way
1476         --  further stream read operations will work correctly, and the
1477         --  effect on text processing is a little weird, but what can
1478         --  be expected if stream and text input are mixed this way?
1479
1480         if File.Before_LM_PM then
1481            Discard_ch := ungetc (PM, File.Stream);
1482            File.Before_LM_PM := False;
1483         end if;
1484
1485         File.Before_LM := False;
1486
1487         Item (Item'First) := Stream_Element (Character'Pos (ASCII.LF));
1488
1489         if Item'Length = 1 then
1490            Last := Item'Last;
1491
1492         else
1493            Last :=
1494              Item'First +
1495                Stream_Element_Offset
1496                  (fread (buffer => Item'Address,
1497                          index  => size_t (Item'First + 1),
1498                          size   => 1,
1499                          count  => Item'Length - 1,
1500                          stream => File.Stream));
1501         end if;
1502
1503         return;
1504      end if;
1505
1506      --  Now we do the read. Since this is a text file, it is normally in
1507      --  text mode, but stream data must be read in binary mode, so we
1508      --  temporarily set binary mode for the read, resetting it after.
1509      --  These calls have no effect in a system (like Unix) where there is
1510      --  no distinction between text and binary files.
1511
1512      set_binary_mode (fileno (File.Stream));
1513
1514      Last :=
1515        Item'First +
1516          Stream_Element_Offset
1517            (fread (Item'Address, 1, Item'Length, File.Stream)) - 1;
1518
1519      if Last < Item'Last then
1520         if ferror (File.Stream) /= 0 then
1521            raise Device_Error;
1522         end if;
1523      end if;
1524
1525      set_text_mode (fileno (File.Stream));
1526   end Read;
1527
1528   -----------
1529   -- Reset --
1530   -----------
1531
1532   procedure Reset
1533     (File : in out File_Type;
1534      Mode : File_Mode)
1535   is
1536   begin
1537      --  Don't allow change of mode for current file (RM A.10.2(5))
1538
1539      if (File = Current_In  or else
1540          File = Current_Out or else
1541          File = Current_Error)
1542        and then To_FCB (Mode) /= File.Mode
1543      then
1544         raise Mode_Error;
1545      end if;
1546
1547      Terminate_Line (File);
1548      FIO.Reset (AP (File)'Unrestricted_Access, To_FCB (Mode));
1549      File.Page := 1;
1550      File.Line := 1;
1551      File.Col  := 1;
1552      File.Line_Length := 0;
1553      File.Page_Length := 0;
1554      File.Before_LM := False;
1555      File.Before_LM_PM := False;
1556   end Reset;
1557
1558   procedure Reset (File : in out File_Type) is
1559   begin
1560      Terminate_Line (File);
1561      FIO.Reset (AP (File)'Unrestricted_Access);
1562      File.Page := 1;
1563      File.Line := 1;
1564      File.Col  := 1;
1565      File.Line_Length := 0;
1566      File.Page_Length := 0;
1567      File.Before_LM := False;
1568      File.Before_LM_PM := False;
1569   end Reset;
1570
1571   -------------
1572   -- Set_Col --
1573   -------------
1574
1575   procedure Set_Col
1576     (File : File_Type;
1577      To   : Positive_Count)
1578   is
1579      ch : int;
1580
1581   begin
1582      --  Raise Constraint_Error if out of range value. The reason for this
1583      --  explicit test is that we don't want junk values around, even if
1584      --  checks are off in the caller.
1585
1586      if not To'Valid then
1587         raise Constraint_Error;
1588      end if;
1589
1590      FIO.Check_File_Open (AP (File));
1591
1592      --  Output case
1593
1594      if Mode (File) >= Out_File then
1595
1596         --  Error if we attempt to set Col to a value greater than the
1597         --  maximum permissible line length.
1598
1599         if File.Line_Length /= 0 and then To > File.Line_Length then
1600            raise Layout_Error;
1601         end if;
1602
1603         --  If we are behind current position, then go to start of new line
1604
1605         if To < File.Col then
1606            New_Line (File);
1607         end if;
1608
1609         --  Loop to output blanks till we are at the required column
1610
1611         while File.Col < To loop
1612            Put (File, ' ');
1613         end loop;
1614
1615      --  Input case
1616
1617      else
1618         --  If we are logically before a LM, but physically after it, the
1619         --  file position still reflects the position before the LM, so eat
1620         --  it now and adjust the file position appropriately.
1621
1622         if File.Before_LM then
1623            File.Before_LM := False;
1624            File.Before_LM_PM := False;
1625            File.Line := File.Line + 1;
1626            File.Col := 1;
1627         end if;
1628
1629         --  Loop reading characters till we get one at the required Col value
1630
1631         loop
1632            --  Read next character. The reason we have to read ahead is to
1633            --  skip formatting characters, the effect of Set_Col is to set
1634            --  us to a real character with the right Col value, and format
1635            --  characters don't count.
1636
1637            ch := Getc (File);
1638
1639            --  Error if we hit an end of file
1640
1641            if ch = EOF then
1642               raise End_Error;
1643
1644            --  If line mark, eat it and adjust file position
1645
1646            elsif ch = LM then
1647               File.Line := File.Line + 1;
1648               File.Col := 1;
1649
1650            --  If recognized page mark, eat it, and adjust file position
1651
1652            elsif ch = PM and then File.Is_Regular_File then
1653               File.Page := File.Page + 1;
1654               File.Line := 1;
1655               File.Col := 1;
1656
1657            --  Otherwise this is the character we are looking for, so put it
1658            --  back in the input stream (we have not adjusted the file
1659            --  position yet, so everything is set right after this ungetc).
1660
1661            elsif To = File.Col then
1662               Ungetc (ch, File);
1663               return;
1664
1665            --  Keep skipping characters if we are not there yet, updating the
1666            --  file position past the skipped character.
1667
1668            else
1669               File.Col := File.Col + 1;
1670            end if;
1671         end loop;
1672      end if;
1673   end Set_Col;
1674
1675   procedure Set_Col (To : Positive_Count) is
1676   begin
1677      Set_Col (Current_Out, To);
1678   end Set_Col;
1679
1680   ---------------
1681   -- Set_Error --
1682   ---------------
1683
1684   procedure Set_Error (File : File_Type) is
1685   begin
1686      FIO.Check_Write_Status (AP (File));
1687      Current_Err := File;
1688   end Set_Error;
1689
1690   ---------------
1691   -- Set_Input --
1692   ---------------
1693
1694   procedure Set_Input (File : File_Type) is
1695   begin
1696      FIO.Check_Read_Status (AP (File));
1697      Current_In := File;
1698   end Set_Input;
1699
1700   --------------
1701   -- Set_Line --
1702   --------------
1703
1704   procedure Set_Line
1705     (File : File_Type;
1706      To   : Positive_Count)
1707   is
1708   begin
1709      --  Raise Constraint_Error if out of range value. The reason for this
1710      --  explicit test is that we don't want junk values around, even if
1711      --  checks are off in the caller.
1712
1713      if not To'Valid then
1714         raise Constraint_Error;
1715      end if;
1716
1717      FIO.Check_File_Open (AP (File));
1718
1719      if To = File.Line then
1720         return;
1721      end if;
1722
1723      if Mode (File) >= Out_File then
1724         if File.Page_Length /= 0 and then To > File.Page_Length then
1725            raise Layout_Error;
1726         end if;
1727
1728         if To < File.Line then
1729            New_Page (File);
1730         end if;
1731
1732         while File.Line < To loop
1733            New_Line (File);
1734         end loop;
1735
1736      else
1737         while To /= File.Line loop
1738            Skip_Line (File);
1739         end loop;
1740      end if;
1741   end Set_Line;
1742
1743   procedure Set_Line (To : Positive_Count) is
1744   begin
1745      Set_Line (Current_Out, To);
1746   end Set_Line;
1747
1748   ---------------------
1749   -- Set_Line_Length --
1750   ---------------------
1751
1752   procedure Set_Line_Length (File : File_Type; To : Count) is
1753   begin
1754      --  Raise Constraint_Error if out of range value. The reason for this
1755      --  explicit test is that we don't want junk values around, even if
1756      --  checks are off in the caller.
1757
1758      if not To'Valid then
1759         raise Constraint_Error;
1760      end if;
1761
1762      FIO.Check_Write_Status (AP (File));
1763      File.Line_Length := To;
1764   end Set_Line_Length;
1765
1766   procedure Set_Line_Length (To : Count) is
1767   begin
1768      Set_Line_Length (Current_Out, To);
1769   end Set_Line_Length;
1770
1771   ----------------
1772   -- Set_Output --
1773   ----------------
1774
1775   procedure Set_Output (File : File_Type) is
1776   begin
1777      FIO.Check_Write_Status (AP (File));
1778      Current_Out := File;
1779   end Set_Output;
1780
1781   ---------------------
1782   -- Set_Page_Length --
1783   ---------------------
1784
1785   procedure Set_Page_Length (File : File_Type; To : Count) is
1786   begin
1787      --  Raise Constraint_Error if out of range value. The reason for this
1788      --  explicit test is that we don't want junk values around, even if
1789      --  checks are off in the caller.
1790
1791      if not To'Valid then
1792         raise Constraint_Error;
1793      end if;
1794
1795      FIO.Check_Write_Status (AP (File));
1796      File.Page_Length := To;
1797   end Set_Page_Length;
1798
1799   procedure Set_Page_Length (To : Count) is
1800   begin
1801      Set_Page_Length (Current_Out, To);
1802   end Set_Page_Length;
1803
1804   --------------
1805   -- Set_WCEM --
1806   --------------
1807
1808   procedure Set_WCEM (File : in out File_Type) is
1809      Start : Natural;
1810      Stop  : Natural;
1811
1812   begin
1813      FIO.Form_Parameter (File.Form.all, "wcem", Start, Stop);
1814
1815      if Start = 0 then
1816         File.WC_Method := Default_WCEM;
1817
1818      else
1819         if Stop = Start then
1820            for J in WC_Encoding_Letters'Range loop
1821               if File.Form (Start) = WC_Encoding_Letters (J) then
1822                  File.WC_Method := J;
1823                  return;
1824               end if;
1825            end loop;
1826         end if;
1827
1828         Close (File);
1829         raise Use_Error with "invalid WCEM form parameter";
1830      end if;
1831   end Set_WCEM;
1832
1833   ---------------
1834   -- Skip_Line --
1835   ---------------
1836
1837   procedure Skip_Line
1838     (File    : File_Type;
1839      Spacing : Positive_Count := 1)
1840   is
1841      ch : int;
1842
1843   begin
1844      --  Raise Constraint_Error if out of range value. The reason for this
1845      --  explicit test is that we don't want junk values around, even if
1846      --  checks are off in the caller.
1847
1848      if not Spacing'Valid then
1849         raise Constraint_Error;
1850      end if;
1851
1852      FIO.Check_Read_Status (AP (File));
1853
1854      for L in 1 .. Spacing loop
1855         if File.Before_LM then
1856            File.Before_LM := False;
1857
1858            --  Note that if File.Before_LM_PM is currently set, we also have
1859            --  to reset it (because it makes sense for Before_LM_PM to be set
1860            --  only when Before_LM is also set). This is done later on in this
1861            --  subprogram, as soon as Before_LM_PM has been taken into account
1862            --  for the purpose of page and line counts.
1863
1864         else
1865            ch := Getc (File);
1866
1867            --  If at end of file now, then immediately raise End_Error. Note
1868            --  that we can never be positioned between a line mark and a page
1869            --  mark, so if we are at the end of file, we cannot logically be
1870            --  before the implicit page mark that is at the end of the file.
1871
1872            --  For the same reason, we do not need an explicit check for a
1873            --  page mark. If there is a FF in the middle of a line, the file
1874            --  is not in canonical format and we do not care about the page
1875            --  numbers for files other than ones in canonical format.
1876
1877            if ch = EOF then
1878               raise End_Error;
1879            end if;
1880
1881            --  If not at end of file, then loop till we get to an LM or EOF.
1882            --  The latter case happens only in non-canonical files where the
1883            --  last line is not terminated by LM, but we don't want to blow
1884            --  up for such files, so we assume an implicit LM in this case.
1885
1886            loop
1887               exit when ch = LM or else ch = EOF;
1888               ch := Getc (File);
1889            end loop;
1890         end if;
1891
1892         --  We have got past a line mark, now, for a regular file only,
1893         --  see if a page mark immediately follows this line mark and
1894         --  if so, skip past the page mark as well. We do not do this
1895         --  for non-regular files, since it would cause an undesirable
1896         --  wait for an additional character.
1897
1898         File.Col := 1;
1899         File.Line := File.Line + 1;
1900
1901         if File.Before_LM_PM then
1902            File.Page := File.Page + 1;
1903            File.Line := 1;
1904            File.Before_LM_PM := False;
1905
1906         elsif File.Is_Regular_File then
1907            ch := Getc (File);
1908
1909            --  Page mark can be explicit, or implied at the end of the file
1910
1911            if (ch = PM or else ch = EOF)
1912              and then File.Is_Regular_File
1913            then
1914               File.Page := File.Page + 1;
1915               File.Line := 1;
1916            else
1917               Ungetc (ch, File);
1918            end if;
1919         end if;
1920      end loop;
1921
1922      File.Before_Upper_Half_Character := False;
1923   end Skip_Line;
1924
1925   procedure Skip_Line (Spacing : Positive_Count := 1) is
1926   begin
1927      Skip_Line (Current_In, Spacing);
1928   end Skip_Line;
1929
1930   ---------------
1931   -- Skip_Page --
1932   ---------------
1933
1934   procedure Skip_Page (File : File_Type) is
1935      ch : int;
1936
1937   begin
1938      FIO.Check_Read_Status (AP (File));
1939
1940      --  If at page mark already, just skip it
1941
1942      if File.Before_LM_PM then
1943         File.Before_LM := False;
1944         File.Before_LM_PM := False;
1945         File.Page := File.Page + 1;
1946         File.Line := 1;
1947         File.Col  := 1;
1948         return;
1949      end if;
1950
1951      --  This is a bit tricky, if we are logically before an LM then
1952      --  it is not an error if we are at an end of file now, since we
1953      --  are not really at it.
1954
1955      if File.Before_LM then
1956         File.Before_LM := False;
1957         File.Before_LM_PM := False;
1958         ch := Getc (File);
1959
1960      --  Otherwise we do raise End_Error if we are at the end of file now
1961
1962      else
1963         ch := Getc (File);
1964
1965         if ch = EOF then
1966            raise End_Error;
1967         end if;
1968      end if;
1969
1970      --  Now we can just rumble along to the next page mark, or to the
1971      --  end of file, if that comes first. The latter case happens when
1972      --  the page mark is implied at the end of file.
1973
1974      loop
1975         exit when ch = EOF
1976           or else (ch = PM and then File.Is_Regular_File);
1977         ch := Getc (File);
1978      end loop;
1979
1980      File.Page := File.Page + 1;
1981      File.Line := 1;
1982      File.Col  := 1;
1983      File.Before_Upper_Half_Character := False;
1984   end Skip_Page;
1985
1986   procedure Skip_Page is
1987   begin
1988      Skip_Page (Current_In);
1989   end Skip_Page;
1990
1991   --------------------
1992   -- Standard_Error --
1993   --------------------
1994
1995   function Standard_Error return File_Type is
1996   begin
1997      return Standard_Err;
1998   end Standard_Error;
1999
2000   function Standard_Error return File_Access is
2001   begin
2002      return Standard_Err'Access;
2003   end Standard_Error;
2004
2005   --------------------
2006   -- Standard_Input --
2007   --------------------
2008
2009   function Standard_Input return File_Type is
2010   begin
2011      return Standard_In;
2012   end Standard_Input;
2013
2014   function Standard_Input return File_Access is
2015   begin
2016      return Standard_In'Access;
2017   end Standard_Input;
2018
2019   ---------------------
2020   -- Standard_Output --
2021   ---------------------
2022
2023   function Standard_Output return File_Type is
2024   begin
2025      return Standard_Out;
2026   end Standard_Output;
2027
2028   function Standard_Output return File_Access is
2029   begin
2030      return Standard_Out'Access;
2031   end Standard_Output;
2032
2033   --------------------
2034   -- Terminate_Line --
2035   --------------------
2036
2037   procedure Terminate_Line (File : File_Type) is
2038   begin
2039      FIO.Check_File_Open (AP (File));
2040
2041      --  For file other than In_File, test for needing to terminate last line
2042
2043      if Mode (File) /= In_File then
2044
2045         --  If not at start of line definition need new line
2046
2047         if File.Col /= 1 then
2048            New_Line (File);
2049
2050         --  For files other than standard error and standard output, we
2051         --  make sure that an empty file has a single line feed, so that
2052         --  it is properly formatted. We avoid this for the standard files
2053         --  because it is too much of a nuisance to have these odd line
2054         --  feeds when nothing has been written to the file.
2055
2056         --  We also avoid this for files opened in append mode, in
2057         --  accordance with (RM A.8.2(10))
2058
2059         elsif (File /= Standard_Err and then File /= Standard_Out)
2060           and then (File.Line = 1 and then File.Page = 1)
2061           and then Mode (File) = Out_File
2062         then
2063            New_Line (File);
2064         end if;
2065      end if;
2066   end Terminate_Line;
2067
2068   ------------
2069   -- Ungetc --
2070   ------------
2071
2072   procedure Ungetc (ch : int; File : File_Type) is
2073   begin
2074      if ch /= EOF then
2075         if ungetc (ch, File.Stream) = EOF then
2076            raise Device_Error;
2077         end if;
2078      end if;
2079   end Ungetc;
2080
2081   -----------
2082   -- Write --
2083   -----------
2084
2085   --  This is the primitive Stream Write routine, used when a Text_IO file
2086   --  is treated directly as a stream using Text_IO.Streams.Stream.
2087
2088   procedure Write
2089     (File : in out Text_AFCB;
2090      Item : Stream_Element_Array)
2091   is
2092      pragma Warnings (Off, File);
2093      --  Because in this implementation we don't need IN OUT, we only read
2094
2095      function Has_Translated_Characters return Boolean;
2096      --  return True if Item array contains a character which will be
2097      --  translated under the text file mode. There is only one such
2098      --  character under DOS based systems which is character 10.
2099
2100      text_translation_required : Boolean;
2101      for text_translation_required'Size use Character'Size;
2102      pragma Import (C, text_translation_required,
2103                     "__gnat_text_translation_required");
2104
2105      Siz : constant size_t := Item'Length;
2106
2107      -------------------------------
2108      -- Has_Translated_Characters --
2109      -------------------------------
2110
2111      function Has_Translated_Characters return Boolean is
2112      begin
2113         for K in Item'Range loop
2114            if Item (K) = 10 then
2115               return True;
2116            end if;
2117         end loop;
2118         return False;
2119      end Has_Translated_Characters;
2120
2121      Needs_Binary_Write : constant Boolean :=
2122        text_translation_required and then Has_Translated_Characters;
2123
2124   --  Start of processing for Write
2125
2126   begin
2127      if File.Mode = FCB.In_File then
2128         raise Mode_Error;
2129      end if;
2130
2131      --  Now we do the write. Since this is a text file, it is normally in
2132      --  text mode, but stream data must be written in binary mode, so we
2133      --  temporarily set binary mode for the write, resetting it after. This
2134      --  is done only if needed (i.e. there is some characters in Item which
2135      --  needs to be written using the binary mode).
2136      --  These calls have no effect in a system (like Unix) where there is
2137      --  no distinction between text and binary files.
2138
2139      --  Since the character translation is done at the time the buffer is
2140      --  written (this is true under Windows) we first flush current buffer
2141      --  with text mode if needed.
2142
2143      if Needs_Binary_Write then
2144         if fflush (File.Stream) = -1 then
2145            raise Device_Error;
2146         end if;
2147
2148         set_binary_mode (fileno (File.Stream));
2149      end if;
2150
2151      if fwrite (Item'Address, 1, Siz, File.Stream) /= Siz then
2152         raise Device_Error;
2153      end if;
2154
2155      --  At this point we need to flush the buffer using the binary mode then
2156      --  we reset to text mode.
2157
2158      if Needs_Binary_Write then
2159         if fflush (File.Stream) = -1 then
2160            raise Device_Error;
2161         end if;
2162
2163         set_text_mode (fileno (File.Stream));
2164      end if;
2165   end Write;
2166
2167begin
2168   --  Initialize Standard Files
2169
2170   for J in WC_Encoding_Method loop
2171      if WC_Encoding = WC_Encoding_Letters (J) then
2172         Default_WCEM := J;
2173      end if;
2174   end loop;
2175
2176   Initialize_Standard_Files;
2177
2178   FIO.Chain_File (AP (Standard_In));
2179   FIO.Chain_File (AP (Standard_Out));
2180   FIO.Chain_File (AP (Standard_Err));
2181
2182end Ada.Text_IO;
2183