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) 1992-2013, 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 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. In
697   --  particular the standard implementation uses low level stuff that is
698   --  not appropriate for the JVM and .NET implementations.
699
700   procedure Get_Line
701     (Item : out String;
702      Last : out Natural)
703   is
704   begin
705      Get_Line (Current_In, Item, Last);
706   end Get_Line;
707
708   function Get_Line (File : File_Type) return String is
709      Buffer : String (1 .. 500);
710      Last   : Natural;
711
712      function Get_Rest (S : String) return String;
713      --  This is a recursive function that reads the rest of the line and
714      --  returns it. S is the part read so far.
715
716      --------------
717      -- Get_Rest --
718      --------------
719
720      function Get_Rest (S : String) return String is
721
722         --  Each time we allocate a buffer the same size as what we have
723         --  read so far. This limits us to a logarithmic number of calls
724         --  to Get_Rest and also ensures only a linear use of stack space.
725
726         Buffer : String (1 .. S'Length);
727         Last   : Natural;
728
729      begin
730         Get_Line (File, Buffer, Last);
731
732         declare
733            R : constant String := S & Buffer (1 .. Last);
734         begin
735            if Last < Buffer'Last then
736               return R;
737            else
738               return Get_Rest (R);
739            end if;
740         end;
741      end Get_Rest;
742
743   --  Start of processing for Get_Line
744
745   begin
746      Get_Line (File, Buffer, Last);
747
748      if Last < Buffer'Last then
749         return Buffer (1 .. Last);
750      else
751         return Get_Rest (Buffer (1 .. Last));
752      end if;
753   end Get_Line;
754
755   function Get_Line return String is
756   begin
757      return Get_Line (Current_In);
758   end Get_Line;
759
760   -------------------------
761   -- Get_Upper_Half_Char --
762   -------------------------
763
764   function Get_Upper_Half_Char
765     (C    : Character;
766      File : File_Type) return Character
767   is
768      Result : Wide_Character;
769
770      function In_Char return Character;
771      --  Function used to obtain additional characters it the wide character
772      --  sequence is more than one character long.
773
774      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
775
776      -------------
777      -- In_Char --
778      -------------
779
780      function In_Char return Character is
781         ch : constant Integer := Getc (File);
782      begin
783         if ch = EOF then
784            raise End_Error;
785         else
786            return Character'Val (ch);
787         end if;
788      end In_Char;
789
790   --  Start of processing for Get_Upper_Half_Char
791
792   begin
793      Result := WC_In (C, File.WC_Method);
794
795      if Wide_Character'Pos (Result) > 16#FF# then
796         raise Constraint_Error with
797           "invalid wide character in Text_'I'O input";
798      else
799         return Character'Val (Wide_Character'Pos (Result));
800      end if;
801   end Get_Upper_Half_Char;
802
803   -------------------------------
804   -- Get_Upper_Half_Char_Immed --
805   -------------------------------
806
807   function Get_Upper_Half_Char_Immed
808     (C    : Character;
809      File : File_Type) return Character
810   is
811      Result : Wide_Character;
812
813      function In_Char return Character;
814      --  Function used to obtain additional characters it the wide character
815      --  sequence is more than one character long.
816
817      function WC_In is new Char_Sequence_To_Wide_Char (In_Char);
818
819      -------------
820      -- In_Char --
821      -------------
822
823      function In_Char return Character is
824         ch : constant Integer := Getc_Immed (File);
825      begin
826         if ch = EOF then
827            raise End_Error;
828         else
829            return Character'Val (ch);
830         end if;
831      end In_Char;
832
833   --  Start of processing for Get_Upper_Half_Char_Immed
834
835   begin
836      Result := WC_In (C, File.WC_Method);
837
838      if Wide_Character'Pos (Result) > 16#FF# then
839         raise Constraint_Error with
840           "invalid wide character in Text_'I'O input";
841      else
842         return Character'Val (Wide_Character'Pos (Result));
843      end if;
844   end Get_Upper_Half_Char_Immed;
845
846   ----------
847   -- Getc --
848   ----------
849
850   function Getc (File : File_Type) return int is
851      ch : int;
852
853   begin
854      ch := fgetc (File.Stream);
855
856      if ch = EOF and then ferror (File.Stream) /= 0 then
857         raise Device_Error;
858      else
859         return ch;
860      end if;
861   end Getc;
862
863   ----------------
864   -- Getc_Immed --
865   ----------------
866
867   function Getc_Immed (File : File_Type) return int is
868      ch          : int;
869      end_of_file : int;
870
871      procedure getc_immediate
872        (stream : FILEs; ch : out int; end_of_file : out int);
873      pragma Import (C, getc_immediate, "getc_immediate");
874
875   begin
876      FIO.Check_Read_Status (AP (File));
877
878      if File.Before_LM then
879         File.Before_LM := False;
880         File.Before_LM_PM := False;
881         ch := LM;
882
883      else
884         getc_immediate (File.Stream, ch, end_of_file);
885
886         if ferror (File.Stream) /= 0 then
887            raise Device_Error;
888         elsif end_of_file /= 0 then
889            return EOF;
890         end if;
891      end if;
892
893      return ch;
894   end Getc_Immed;
895
896   ------------------------------
897   -- Has_Upper_Half_Character --
898   ------------------------------
899
900   function Has_Upper_Half_Character (Item : String) return Boolean is
901   begin
902      for J in Item'Range loop
903         if Character'Pos (Item (J)) >= 16#80# then
904            return True;
905         end if;
906      end loop;
907
908      return False;
909   end Has_Upper_Half_Character;
910
911   -------------------------------
912   -- Initialize_Standard_Files --
913   -------------------------------
914
915   procedure Initialize_Standard_Files is
916   begin
917      Standard_Err.Stream            := stderr;
918      Standard_Err.Name              := Err_Name'Access;
919      Standard_Err.Form              := Null_Str'Unrestricted_Access;
920      Standard_Err.Mode              := FCB.Out_File;
921      Standard_Err.Is_Regular_File   := is_regular_file (fileno (stderr)) /= 0;
922      Standard_Err.Is_Temporary_File := False;
923      Standard_Err.Is_System_File    := True;
924      Standard_Err.Is_Text_File      := True;
925      Standard_Err.Access_Method     := 'T';
926      Standard_Err.Self              := Standard_Err;
927      Standard_Err.WC_Method         := Default_WCEM;
928
929      Standard_In.Stream             := stdin;
930      Standard_In.Name               := In_Name'Access;
931      Standard_In.Form               := Null_Str'Unrestricted_Access;
932      Standard_In.Mode               := FCB.In_File;
933      Standard_In.Is_Regular_File    := is_regular_file (fileno (stdin)) /= 0;
934      Standard_In.Is_Temporary_File  := False;
935      Standard_In.Is_System_File     := True;
936      Standard_In.Is_Text_File       := True;
937      Standard_In.Access_Method      := 'T';
938      Standard_In.Self               := Standard_In;
939      Standard_In.WC_Method          := Default_WCEM;
940
941      Standard_Out.Stream            := stdout;
942      Standard_Out.Name              := Out_Name'Access;
943      Standard_Out.Form              := Null_Str'Unrestricted_Access;
944      Standard_Out.Mode              := FCB.Out_File;
945      Standard_Out.Is_Regular_File   := is_regular_file (fileno (stdout)) /= 0;
946      Standard_Out.Is_Temporary_File := False;
947      Standard_Out.Is_System_File    := True;
948      Standard_Out.Is_Text_File      := True;
949      Standard_Out.Access_Method     := 'T';
950      Standard_Out.Self              := Standard_Out;
951      Standard_Out.WC_Method         := Default_WCEM;
952
953      FIO.Make_Unbuffered (AP (Standard_Out));
954      FIO.Make_Unbuffered (AP (Standard_Err));
955   end Initialize_Standard_Files;
956
957   -------------
958   -- Is_Open --
959   -------------
960
961   function Is_Open (File : File_Type) return Boolean is
962   begin
963      return FIO.Is_Open (AP (File));
964   end Is_Open;
965
966   ----------
967   -- Line --
968   ----------
969
970   --  Note: we assume that it is impossible in practice for the line
971   --  to exceed the value of Count'Last, i.e. no check is required for
972   --  overflow raising layout error.
973
974   function Line (File : File_Type) return Positive_Count is
975   begin
976      FIO.Check_File_Open (AP (File));
977      return File.Line;
978   end Line;
979
980   function Line return Positive_Count is
981   begin
982      return Line (Current_Out);
983   end Line;
984
985   -----------------
986   -- Line_Length --
987   -----------------
988
989   function Line_Length (File : File_Type) return Count is
990   begin
991      FIO.Check_Write_Status (AP (File));
992      return File.Line_Length;
993   end Line_Length;
994
995   function Line_Length return Count is
996   begin
997      return Line_Length (Current_Out);
998   end Line_Length;
999
1000   ----------------
1001   -- Look_Ahead --
1002   ----------------
1003
1004   procedure Look_Ahead
1005     (File        : File_Type;
1006      Item        : out Character;
1007      End_Of_Line : out Boolean)
1008   is
1009      ch : int;
1010
1011   begin
1012      FIO.Check_Read_Status (AP (File));
1013
1014      --  If we are logically before a line mark, we can return immediately
1015
1016      if File.Before_LM then
1017         End_Of_Line := True;
1018         Item := ASCII.NUL;
1019
1020      --  If we are before an upper half character just return it (this can
1021      --  happen if there are two calls to Look_Ahead in a row).
1022
1023      elsif File.Before_Upper_Half_Character then
1024         End_Of_Line := False;
1025         Item := File.Saved_Upper_Half_Character;
1026
1027      --  Otherwise we must read a character from the input stream
1028
1029      else
1030         ch := Getc (File);
1031
1032         if ch = LM
1033           or else ch = EOF
1034           or else (ch = PM and then File.Is_Regular_File)
1035         then
1036            End_Of_Line := True;
1037            Ungetc (ch, File);
1038            Item := ASCII.NUL;
1039
1040         --  Case where character obtained does not represent the start of an
1041         --  encoded sequence so it stands for itself and we can unget it with
1042         --  no difficulty.
1043
1044         elsif not Is_Start_Of_Encoding
1045                     (Character'Val (ch), File.WC_Method)
1046         then
1047            End_Of_Line := False;
1048            Ungetc (ch, File);
1049            Item := Character'Val (ch);
1050
1051         --  For the start of an encoding, we read the character using the
1052         --  Get_Upper_Half_Char routine. It will occupy more than one byte
1053         --  so we can't put it back with ungetc. Instead we save it in the
1054         --  control block, setting a flag that everyone interested in reading
1055         --  characters must test before reading the stream.
1056
1057         else
1058            Item := Get_Upper_Half_Char (Character'Val (ch), File);
1059            End_Of_Line := False;
1060            File.Saved_Upper_Half_Character := Item;
1061            File.Before_Upper_Half_Character := True;
1062         end if;
1063      end if;
1064   end Look_Ahead;
1065
1066   procedure Look_Ahead
1067     (Item        : out Character;
1068      End_Of_Line : out Boolean)
1069   is
1070   begin
1071      Look_Ahead (Current_In, Item, End_Of_Line);
1072   end Look_Ahead;
1073
1074   ----------
1075   -- Mode --
1076   ----------
1077
1078   function Mode (File : File_Type) return File_Mode is
1079   begin
1080      return To_TIO (FIO.Mode (AP (File)));
1081   end Mode;
1082
1083   ----------
1084   -- Name --
1085   ----------
1086
1087   function Name (File : File_Type) return String is
1088   begin
1089      return FIO.Name (AP (File));
1090   end Name;
1091
1092   --------------
1093   -- New_Line --
1094   --------------
1095
1096   procedure New_Line
1097     (File    : File_Type;
1098      Spacing : Positive_Count := 1)
1099   is
1100   begin
1101      --  Raise Constraint_Error if out of range value. The reason for this
1102      --  explicit test is that we don't want junk values around, even if
1103      --  checks are off in the caller.
1104
1105      if not Spacing'Valid then
1106         raise Constraint_Error;
1107      end if;
1108
1109      FIO.Check_Write_Status (AP (File));
1110
1111      for K in 1 .. Spacing loop
1112         Putc (LM, File);
1113         File.Line := File.Line + 1;
1114
1115         if File.Page_Length /= 0
1116           and then File.Line > File.Page_Length
1117         then
1118            Putc (PM, File);
1119            File.Line := 1;
1120            File.Page := File.Page + 1;
1121         end if;
1122      end loop;
1123
1124      File.Col := 1;
1125   end New_Line;
1126
1127   procedure New_Line (Spacing : Positive_Count := 1) is
1128   begin
1129      New_Line (Current_Out, Spacing);
1130   end New_Line;
1131
1132   --------------
1133   -- New_Page --
1134   --------------
1135
1136   procedure New_Page (File : File_Type) is
1137   begin
1138      FIO.Check_Write_Status (AP (File));
1139
1140      if File.Col /= 1 or else File.Line = 1 then
1141         Putc (LM, File);
1142      end if;
1143
1144      Putc (PM, File);
1145      File.Page := File.Page + 1;
1146      File.Line := 1;
1147      File.Col := 1;
1148   end New_Page;
1149
1150   procedure New_Page is
1151   begin
1152      New_Page (Current_Out);
1153   end New_Page;
1154
1155   -----------
1156   -- Nextc --
1157   -----------
1158
1159   function Nextc (File : File_Type) return int is
1160      ch : int;
1161
1162   begin
1163      ch := fgetc (File.Stream);
1164
1165      if ch = EOF then
1166         if ferror (File.Stream) /= 0 then
1167            raise Device_Error;
1168         end if;
1169
1170      else
1171         if ungetc (ch, File.Stream) = EOF then
1172            raise Device_Error;
1173         end if;
1174      end if;
1175
1176      return ch;
1177   end Nextc;
1178
1179   ----------
1180   -- Open --
1181   ----------
1182
1183   procedure Open
1184     (File : in out File_Type;
1185      Mode : File_Mode;
1186      Name : String;
1187      Form : String := "")
1188   is
1189      Dummy_File_Control_Block : Text_AFCB;
1190      pragma Warnings (Off, Dummy_File_Control_Block);
1191      --  Yes, we know this is never assigned a value, only the tag
1192      --  is used for dispatching purposes, so that's expected.
1193
1194   begin
1195      FIO.Open (File_Ptr  => AP (File),
1196                Dummy_FCB => Dummy_File_Control_Block,
1197                Mode      => To_FCB (Mode),
1198                Name      => Name,
1199                Form      => Form,
1200                Amethod   => 'T',
1201                Creat     => False,
1202                Text      => True);
1203
1204      File.Self := File;
1205      Set_WCEM (File);
1206   end Open;
1207
1208   ----------
1209   -- Page --
1210   ----------
1211
1212   --  Note: we assume that it is impossible in practice for the page
1213   --  to exceed the value of Count'Last, i.e. no check is required for
1214   --  overflow raising layout error.
1215
1216   function Page (File : File_Type) return Positive_Count is
1217   begin
1218      FIO.Check_File_Open (AP (File));
1219      return File.Page;
1220   end Page;
1221
1222   function Page return Positive_Count is
1223   begin
1224      return Page (Current_Out);
1225   end Page;
1226
1227   -----------------
1228   -- Page_Length --
1229   -----------------
1230
1231   function Page_Length (File : File_Type) return Count is
1232   begin
1233      FIO.Check_Write_Status (AP (File));
1234      return File.Page_Length;
1235   end Page_Length;
1236
1237   function Page_Length return Count is
1238   begin
1239      return Page_Length (Current_Out);
1240   end Page_Length;
1241
1242   ---------
1243   -- Put --
1244   ---------
1245
1246   procedure Put
1247     (File : File_Type;
1248      Item : Character)
1249   is
1250   begin
1251      FIO.Check_Write_Status (AP (File));
1252
1253      if File.Line_Length /= 0 and then File.Col > File.Line_Length then
1254         New_Line (File);
1255      end if;
1256
1257      --  If lower half character, or brackets encoding, output directly
1258
1259      if Character'Pos (Item) < 16#80#
1260        or else File.WC_Method = WCEM_Brackets
1261      then
1262         if fputc (Character'Pos (Item), File.Stream) = EOF then
1263            raise Device_Error;
1264         end if;
1265
1266      --  Case of upper half character with non-brackets encoding
1267
1268      else
1269         Put_Encoded (File, Item);
1270      end if;
1271
1272      File.Col := File.Col + 1;
1273   end Put;
1274
1275   procedure Put (Item : Character) is
1276   begin
1277      Put (Current_Out, Item);
1278   end Put;
1279
1280   ---------
1281   -- Put --
1282   ---------
1283
1284   procedure Put
1285     (File : File_Type;
1286      Item : String)
1287   is
1288   begin
1289      FIO.Check_Write_Status (AP (File));
1290
1291      --  Only have something to do if string is non-null
1292
1293      if Item'Length > 0 then
1294
1295         --  If we have bounded lines, or if the file encoding is other than
1296         --  Brackets and the string has at least one upper half character,
1297         --  then output the string character by character.
1298
1299         if File.Line_Length /= 0
1300           or else (File.WC_Method /= WCEM_Brackets
1301                      and then Has_Upper_Half_Character (Item))
1302         then
1303            for J in Item'Range loop
1304               Put (File, Item (J));
1305            end loop;
1306
1307         --  Otherwise we can output the entire string at once. Note that if
1308         --  there are LF or FF characters in the string, we do not bother to
1309         --  count them as line or page terminators.
1310
1311         else
1312            FIO.Write_Buf (AP (File), Item'Address, Item'Length);
1313            File.Col := File.Col + Item'Length;
1314         end if;
1315      end if;
1316   end Put;
1317
1318   procedure Put (Item : String) is
1319   begin
1320      Put (Current_Out, Item);
1321   end Put;
1322
1323   -----------------
1324   -- Put_Encoded --
1325   -----------------
1326
1327   procedure Put_Encoded (File : File_Type; Char : Character) is
1328      procedure Out_Char (C : Character);
1329      --  Procedure to output one character of an upper half encoded sequence
1330
1331      procedure WC_Out is new Wide_Char_To_Char_Sequence (Out_Char);
1332
1333      --------------
1334      -- Out_Char --
1335      --------------
1336
1337      procedure Out_Char (C : Character) is
1338      begin
1339         Putc (Character'Pos (C), File);
1340      end Out_Char;
1341
1342   --  Start of processing for Put_Encoded
1343
1344   begin
1345      WC_Out (Wide_Character'Val (Character'Pos (Char)), File.WC_Method);
1346   end Put_Encoded;
1347
1348   --------------
1349   -- Put_Line --
1350   --------------
1351
1352   procedure Put_Line
1353     (File : File_Type;
1354      Item : String)
1355   is
1356      Ilen   : Natural := Item'Length;
1357      Istart : Natural := Item'First;
1358
1359   begin
1360      FIO.Check_Write_Status (AP (File));
1361
1362      --  If we have bounded lines, or if the file encoding is other than
1363      --  Brackets and the string has at least one upper half character, then
1364      --  output the string character by character.
1365
1366      if File.Line_Length /= 0
1367        or else (File.WC_Method /= WCEM_Brackets
1368                   and then Has_Upper_Half_Character (Item))
1369      then
1370         for J in Item'Range loop
1371            Put (File, Item (J));
1372         end loop;
1373
1374         New_Line (File);
1375         return;
1376      end if;
1377
1378      --  Normal case where we do not need to output character by character
1379
1380      --  We setup a single string that has the necessary terminators and
1381      --  then write it with a single call. The reason for doing this is
1382      --  that it gives better behavior for the use of Put_Line in multi-
1383      --  tasking programs, since often the OS will treat the entire put
1384      --  operation as an atomic operation.
1385
1386      --  We only do this if the message is 512 characters or less in length,
1387      --  since otherwise Put_Line would use an unbounded amount of stack
1388      --  space and could cause undetected stack overflow. If we have a
1389      --  longer string, then output the first part separately to avoid this.
1390
1391      if Ilen > 512 then
1392         FIO.Write_Buf (AP (File), Item'Address, size_t (Ilen - 512));
1393         Istart := Istart + Ilen - 512;
1394         Ilen   := 512;
1395      end if;
1396
1397      --  Now prepare the string with its terminator
1398
1399      declare
1400         Buffer : String (1 .. Ilen + 2);
1401         Plen   : size_t;
1402
1403      begin
1404         Buffer (1 .. Ilen) := Item (Istart .. Item'Last);
1405         Buffer (Ilen + 1) := Character'Val (LM);
1406
1407         if File.Page_Length /= 0
1408           and then File.Line > File.Page_Length
1409         then
1410            Buffer (Ilen + 2) := Character'Val (PM);
1411            Plen := size_t (Ilen) + 2;
1412            File.Line := 1;
1413            File.Page := File.Page + 1;
1414
1415         else
1416            Plen := size_t (Ilen) + 1;
1417            File.Line := File.Line + 1;
1418         end if;
1419
1420         FIO.Write_Buf (AP (File), Buffer'Address, Plen);
1421
1422         File.Col := 1;
1423      end;
1424   end Put_Line;
1425
1426   procedure Put_Line (Item : String) is
1427   begin
1428      Put_Line (Current_Out, Item);
1429   end Put_Line;
1430
1431   ----------
1432   -- Putc --
1433   ----------
1434
1435   procedure Putc (ch : int; File : File_Type) is
1436   begin
1437      if fputc (ch, File.Stream) = EOF then
1438         raise Device_Error;
1439      end if;
1440   end Putc;
1441
1442   ----------
1443   -- Read --
1444   ----------
1445
1446   --  This is the primitive Stream Read routine, used when a Text_IO file
1447   --  is treated directly as a stream using Text_IO.Streams.Stream.
1448
1449   procedure Read
1450     (File : in out Text_AFCB;
1451      Item : out Stream_Element_Array;
1452      Last : out Stream_Element_Offset)
1453   is
1454      Discard_ch : int;
1455      pragma Warnings (Off, Discard_ch);
1456
1457   begin
1458      --  Need to deal with Before_Upper_Half_Character ???
1459
1460      if File.Mode /= FCB.In_File then
1461         raise Mode_Error;
1462      end if;
1463
1464      --  Deal with case where our logical and physical position do not match
1465      --  because of being after an LM or LM-PM sequence when in fact we are
1466      --  logically positioned before it.
1467
1468      if File.Before_LM then
1469
1470         --  If we are before a PM, then it is possible for a stream read
1471         --  to leave us after the LM and before the PM, which is a bit
1472         --  odd. The easiest way to deal with this is to unget the PM,
1473         --  so we are indeed positioned between the characters. This way
1474         --  further stream read operations will work correctly, and the
1475         --  effect on text processing is a little weird, but what can
1476         --  be expected if stream and text input are mixed this way?
1477
1478         if File.Before_LM_PM then
1479            Discard_ch := ungetc (PM, File.Stream);
1480            File.Before_LM_PM := False;
1481         end if;
1482
1483         File.Before_LM := False;
1484
1485         Item (Item'First) := Stream_Element (Character'Pos (ASCII.LF));
1486
1487         if Item'Length = 1 then
1488            Last := Item'Last;
1489
1490         else
1491            Last :=
1492              Item'First +
1493                Stream_Element_Offset
1494                  (fread (buffer => Item'Address,
1495                          index  => size_t (Item'First + 1),
1496                          size   => 1,
1497                          count  => Item'Length - 1,
1498                          stream => File.Stream));
1499         end if;
1500
1501         return;
1502      end if;
1503
1504      --  Now we do the read. Since this is a text file, it is normally in
1505      --  text mode, but stream data must be read in binary mode, so we
1506      --  temporarily set binary mode for the read, resetting it after.
1507      --  These calls have no effect in a system (like Unix) where there is
1508      --  no distinction between text and binary files.
1509
1510      set_binary_mode (fileno (File.Stream));
1511
1512      Last :=
1513        Item'First +
1514          Stream_Element_Offset
1515            (fread (Item'Address, 1, Item'Length, File.Stream)) - 1;
1516
1517      if Last < Item'Last then
1518         if ferror (File.Stream) /= 0 then
1519            raise Device_Error;
1520         end if;
1521      end if;
1522
1523      set_text_mode (fileno (File.Stream));
1524   end Read;
1525
1526   -----------
1527   -- Reset --
1528   -----------
1529
1530   procedure Reset
1531     (File : in out File_Type;
1532      Mode : File_Mode)
1533   is
1534   begin
1535      --  Don't allow change of mode for current file (RM A.10.2(5))
1536
1537      if (File = Current_In  or else
1538          File = Current_Out or else
1539          File = Current_Error)
1540        and then To_FCB (Mode) /= File.Mode
1541      then
1542         raise Mode_Error;
1543      end if;
1544
1545      Terminate_Line (File);
1546      FIO.Reset (AP (File)'Unrestricted_Access, To_FCB (Mode));
1547      File.Page := 1;
1548      File.Line := 1;
1549      File.Col  := 1;
1550      File.Line_Length := 0;
1551      File.Page_Length := 0;
1552      File.Before_LM := False;
1553      File.Before_LM_PM := False;
1554   end Reset;
1555
1556   procedure Reset (File : in out File_Type) is
1557   begin
1558      Terminate_Line (File);
1559      FIO.Reset (AP (File)'Unrestricted_Access);
1560      File.Page := 1;
1561      File.Line := 1;
1562      File.Col  := 1;
1563      File.Line_Length := 0;
1564      File.Page_Length := 0;
1565      File.Before_LM := False;
1566      File.Before_LM_PM := False;
1567   end Reset;
1568
1569   -------------
1570   -- Set_Col --
1571   -------------
1572
1573   procedure Set_Col
1574     (File : File_Type;
1575      To   : Positive_Count)
1576   is
1577      ch : int;
1578
1579   begin
1580      --  Raise Constraint_Error if out of range value. The reason for this
1581      --  explicit test is that we don't want junk values around, even if
1582      --  checks are off in the caller.
1583
1584      if not To'Valid then
1585         raise Constraint_Error;
1586      end if;
1587
1588      FIO.Check_File_Open (AP (File));
1589
1590      --  Output case
1591
1592      if Mode (File) >= Out_File then
1593
1594         --  Error if we attempt to set Col to a value greater than the
1595         --  maximum permissible line length.
1596
1597         if File.Line_Length /= 0 and then To > File.Line_Length then
1598            raise Layout_Error;
1599         end if;
1600
1601         --  If we are behind current position, then go to start of new line
1602
1603         if To < File.Col then
1604            New_Line (File);
1605         end if;
1606
1607         --  Loop to output blanks till we are at the required column
1608
1609         while File.Col < To loop
1610            Put (File, ' ');
1611         end loop;
1612
1613      --  Input case
1614
1615      else
1616         --  If we are logically before a LM, but physically after it, the
1617         --  file position still reflects the position before the LM, so eat
1618         --  it now and adjust the file position appropriately.
1619
1620         if File.Before_LM then
1621            File.Before_LM := False;
1622            File.Before_LM_PM := False;
1623            File.Line := File.Line + 1;
1624            File.Col := 1;
1625         end if;
1626
1627         --  Loop reading characters till we get one at the required Col value
1628
1629         loop
1630            --  Read next character. The reason we have to read ahead is to
1631            --  skip formatting characters, the effect of Set_Col is to set
1632            --  us to a real character with the right Col value, and format
1633            --  characters don't count.
1634
1635            ch := Getc (File);
1636
1637            --  Error if we hit an end of file
1638
1639            if ch = EOF then
1640               raise End_Error;
1641
1642            --  If line mark, eat it and adjust file position
1643
1644            elsif ch = LM then
1645               File.Line := File.Line + 1;
1646               File.Col := 1;
1647
1648            --  If recognized page mark, eat it, and adjust file position
1649
1650            elsif ch = PM and then File.Is_Regular_File then
1651               File.Page := File.Page + 1;
1652               File.Line := 1;
1653               File.Col := 1;
1654
1655            --  Otherwise this is the character we are looking for, so put it
1656            --  back in the input stream (we have not adjusted the file
1657            --  position yet, so everything is set right after this ungetc).
1658
1659            elsif To = File.Col then
1660               Ungetc (ch, File);
1661               return;
1662
1663            --  Keep skipping characters if we are not there yet, updating the
1664            --  file position past the skipped character.
1665
1666            else
1667               File.Col := File.Col + 1;
1668            end if;
1669         end loop;
1670      end if;
1671   end Set_Col;
1672
1673   procedure Set_Col (To : Positive_Count) is
1674   begin
1675      Set_Col (Current_Out, To);
1676   end Set_Col;
1677
1678   ---------------
1679   -- Set_Error --
1680   ---------------
1681
1682   procedure Set_Error (File : File_Type) is
1683   begin
1684      FIO.Check_Write_Status (AP (File));
1685      Current_Err := File;
1686   end Set_Error;
1687
1688   ---------------
1689   -- Set_Input --
1690   ---------------
1691
1692   procedure Set_Input (File : File_Type) is
1693   begin
1694      FIO.Check_Read_Status (AP (File));
1695      Current_In := File;
1696   end Set_Input;
1697
1698   --------------
1699   -- Set_Line --
1700   --------------
1701
1702   procedure Set_Line
1703     (File : File_Type;
1704      To   : Positive_Count)
1705   is
1706   begin
1707      --  Raise Constraint_Error if out of range value. The reason for this
1708      --  explicit test is that we don't want junk values around, even if
1709      --  checks are off in the caller.
1710
1711      if not To'Valid then
1712         raise Constraint_Error;
1713      end if;
1714
1715      FIO.Check_File_Open (AP (File));
1716
1717      if To = File.Line then
1718         return;
1719      end if;
1720
1721      if Mode (File) >= Out_File then
1722         if File.Page_Length /= 0 and then To > File.Page_Length then
1723            raise Layout_Error;
1724         end if;
1725
1726         if To < File.Line then
1727            New_Page (File);
1728         end if;
1729
1730         while File.Line < To loop
1731            New_Line (File);
1732         end loop;
1733
1734      else
1735         while To /= File.Line loop
1736            Skip_Line (File);
1737         end loop;
1738      end if;
1739   end Set_Line;
1740
1741   procedure Set_Line (To : Positive_Count) is
1742   begin
1743      Set_Line (Current_Out, To);
1744   end Set_Line;
1745
1746   ---------------------
1747   -- Set_Line_Length --
1748   ---------------------
1749
1750   procedure Set_Line_Length (File : File_Type; To : Count) is
1751   begin
1752      --  Raise Constraint_Error if out of range value. The reason for this
1753      --  explicit test is that we don't want junk values around, even if
1754      --  checks are off in the caller.
1755
1756      if not To'Valid then
1757         raise Constraint_Error;
1758      end if;
1759
1760      FIO.Check_Write_Status (AP (File));
1761      File.Line_Length := To;
1762   end Set_Line_Length;
1763
1764   procedure Set_Line_Length (To : Count) is
1765   begin
1766      Set_Line_Length (Current_Out, To);
1767   end Set_Line_Length;
1768
1769   ----------------
1770   -- Set_Output --
1771   ----------------
1772
1773   procedure Set_Output (File : File_Type) is
1774   begin
1775      FIO.Check_Write_Status (AP (File));
1776      Current_Out := File;
1777   end Set_Output;
1778
1779   ---------------------
1780   -- Set_Page_Length --
1781   ---------------------
1782
1783   procedure Set_Page_Length (File : File_Type; To : Count) is
1784   begin
1785      --  Raise Constraint_Error if out of range value. The reason for this
1786      --  explicit test is that we don't want junk values around, even if
1787      --  checks are off in the caller.
1788
1789      if not To'Valid then
1790         raise Constraint_Error;
1791      end if;
1792
1793      FIO.Check_Write_Status (AP (File));
1794      File.Page_Length := To;
1795   end Set_Page_Length;
1796
1797   procedure Set_Page_Length (To : Count) is
1798   begin
1799      Set_Page_Length (Current_Out, To);
1800   end Set_Page_Length;
1801
1802   --------------
1803   -- Set_WCEM --
1804   --------------
1805
1806   procedure Set_WCEM (File : in out File_Type) is
1807      Start : Natural;
1808      Stop  : Natural;
1809
1810   begin
1811      File.WC_Method := WCEM_Brackets;
1812      FIO.Form_Parameter (File.Form.all, "wcem", Start, Stop);
1813
1814      if Start = 0 then
1815         File.WC_Method := WCEM_Brackets;
1816
1817      else
1818         if Stop = Start then
1819            for J in WC_Encoding_Letters'Range loop
1820               if File.Form (Start) = WC_Encoding_Letters (J) then
1821                  File.WC_Method := J;
1822                  return;
1823               end if;
1824            end loop;
1825         end if;
1826
1827         Close (File);
1828         raise Use_Error with "invalid WCEM form parameter";
1829      end if;
1830   end Set_WCEM;
1831
1832   ---------------
1833   -- Skip_Line --
1834   ---------------
1835
1836   procedure Skip_Line
1837     (File    : File_Type;
1838      Spacing : Positive_Count := 1)
1839   is
1840      ch : int;
1841
1842   begin
1843      --  Raise Constraint_Error if out of range value. The reason for this
1844      --  explicit test is that we don't want junk values around, even if
1845      --  checks are off in the caller.
1846
1847      if not Spacing'Valid then
1848         raise Constraint_Error;
1849      end if;
1850
1851      FIO.Check_Read_Status (AP (File));
1852
1853      for L in 1 .. Spacing loop
1854         if File.Before_LM then
1855            File.Before_LM := False;
1856
1857            --  Note that if File.Before_LM_PM is currently set, we also have
1858            --  to reset it (because it makes sense for Before_LM_PM to be set
1859            --  only when Before_LM is also set). This is done later on in this
1860            --  subprogram, as soon as Before_LM_PM has been taken into account
1861            --  for the purpose of page and line counts.
1862
1863         else
1864            ch := Getc (File);
1865
1866            --  If at end of file now, then immediately raise End_Error. Note
1867            --  that we can never be positioned between a line mark and a page
1868            --  mark, so if we are at the end of file, we cannot logically be
1869            --  before the implicit page mark that is at the end of the file.
1870
1871            --  For the same reason, we do not need an explicit check for a
1872            --  page mark. If there is a FF in the middle of a line, the file
1873            --  is not in canonical format and we do not care about the page
1874            --  numbers for files other than ones in canonical format.
1875
1876            if ch = EOF then
1877               raise End_Error;
1878            end if;
1879
1880            --  If not at end of file, then loop till we get to an LM or EOF.
1881            --  The latter case happens only in non-canonical files where the
1882            --  last line is not terminated by LM, but we don't want to blow
1883            --  up for such files, so we assume an implicit LM in this case.
1884
1885            loop
1886               exit when ch = LM or else ch = EOF;
1887               ch := Getc (File);
1888            end loop;
1889         end if;
1890
1891         --  We have got past a line mark, now, for a regular file only,
1892         --  see if a page mark immediately follows this line mark and
1893         --  if so, skip past the page mark as well. We do not do this
1894         --  for non-regular files, since it would cause an undesirable
1895         --  wait for an additional character.
1896
1897         File.Col := 1;
1898         File.Line := File.Line + 1;
1899
1900         if File.Before_LM_PM then
1901            File.Page := File.Page + 1;
1902            File.Line := 1;
1903            File.Before_LM_PM := False;
1904
1905         elsif File.Is_Regular_File then
1906            ch := Getc (File);
1907
1908            --  Page mark can be explicit, or implied at the end of the file
1909
1910            if (ch = PM or else ch = EOF)
1911              and then File.Is_Regular_File
1912            then
1913               File.Page := File.Page + 1;
1914               File.Line := 1;
1915            else
1916               Ungetc (ch, File);
1917            end if;
1918         end if;
1919      end loop;
1920
1921      File.Before_Upper_Half_Character := False;
1922   end Skip_Line;
1923
1924   procedure Skip_Line (Spacing : Positive_Count := 1) is
1925   begin
1926      Skip_Line (Current_In, Spacing);
1927   end Skip_Line;
1928
1929   ---------------
1930   -- Skip_Page --
1931   ---------------
1932
1933   procedure Skip_Page (File : File_Type) is
1934      ch : int;
1935
1936   begin
1937      FIO.Check_Read_Status (AP (File));
1938
1939      --  If at page mark already, just skip it
1940
1941      if File.Before_LM_PM then
1942         File.Before_LM := False;
1943         File.Before_LM_PM := False;
1944         File.Page := File.Page + 1;
1945         File.Line := 1;
1946         File.Col  := 1;
1947         return;
1948      end if;
1949
1950      --  This is a bit tricky, if we are logically before an LM then
1951      --  it is not an error if we are at an end of file now, since we
1952      --  are not really at it.
1953
1954      if File.Before_LM then
1955         File.Before_LM := False;
1956         File.Before_LM_PM := False;
1957         ch := Getc (File);
1958
1959      --  Otherwise we do raise End_Error if we are at the end of file now
1960
1961      else
1962         ch := Getc (File);
1963
1964         if ch = EOF then
1965            raise End_Error;
1966         end if;
1967      end if;
1968
1969      --  Now we can just rumble along to the next page mark, or to the
1970      --  end of file, if that comes first. The latter case happens when
1971      --  the page mark is implied at the end of file.
1972
1973      loop
1974         exit when ch = EOF
1975           or else (ch = PM and then File.Is_Regular_File);
1976         ch := Getc (File);
1977      end loop;
1978
1979      File.Page := File.Page + 1;
1980      File.Line := 1;
1981      File.Col  := 1;
1982      File.Before_Upper_Half_Character := False;
1983   end Skip_Page;
1984
1985   procedure Skip_Page is
1986   begin
1987      Skip_Page (Current_In);
1988   end Skip_Page;
1989
1990   --------------------
1991   -- Standard_Error --
1992   --------------------
1993
1994   function Standard_Error return File_Type is
1995   begin
1996      return Standard_Err;
1997   end Standard_Error;
1998
1999   function Standard_Error return File_Access is
2000   begin
2001      return Standard_Err'Access;
2002   end Standard_Error;
2003
2004   --------------------
2005   -- Standard_Input --
2006   --------------------
2007
2008   function Standard_Input return File_Type is
2009   begin
2010      return Standard_In;
2011   end Standard_Input;
2012
2013   function Standard_Input return File_Access is
2014   begin
2015      return Standard_In'Access;
2016   end Standard_Input;
2017
2018   ---------------------
2019   -- Standard_Output --
2020   ---------------------
2021
2022   function Standard_Output return File_Type is
2023   begin
2024      return Standard_Out;
2025   end Standard_Output;
2026
2027   function Standard_Output return File_Access is
2028   begin
2029      return Standard_Out'Access;
2030   end Standard_Output;
2031
2032   --------------------
2033   -- Terminate_Line --
2034   --------------------
2035
2036   procedure Terminate_Line (File : File_Type) is
2037   begin
2038      FIO.Check_File_Open (AP (File));
2039
2040      --  For file other than In_File, test for needing to terminate last line
2041
2042      if Mode (File) /= In_File then
2043
2044         --  If not at start of line definition need new line
2045
2046         if File.Col /= 1 then
2047            New_Line (File);
2048
2049         --  For files other than standard error and standard output, we
2050         --  make sure that an empty file has a single line feed, so that
2051         --  it is properly formatted. We avoid this for the standard files
2052         --  because it is too much of a nuisance to have these odd line
2053         --  feeds when nothing has been written to the file.
2054
2055         --  We also avoid this for files opened in append mode, in
2056         --  accordance with (RM A.8.2(10))
2057
2058         elsif (File /= Standard_Err and then File /= Standard_Out)
2059           and then (File.Line = 1 and then File.Page = 1)
2060           and then Mode (File) = Out_File
2061         then
2062            New_Line (File);
2063         end if;
2064      end if;
2065   end Terminate_Line;
2066
2067   ------------
2068   -- Ungetc --
2069   ------------
2070
2071   procedure Ungetc (ch : int; File : File_Type) is
2072   begin
2073      if ch /= EOF then
2074         if ungetc (ch, File.Stream) = EOF then
2075            raise Device_Error;
2076         end if;
2077      end if;
2078   end Ungetc;
2079
2080   -----------
2081   -- Write --
2082   -----------
2083
2084   --  This is the primitive Stream Write routine, used when a Text_IO file
2085   --  is treated directly as a stream using Text_IO.Streams.Stream.
2086
2087   procedure Write
2088     (File : in out Text_AFCB;
2089      Item : Stream_Element_Array)
2090   is
2091      pragma Warnings (Off, File);
2092      --  Because in this implementation we don't need IN OUT, we only read
2093
2094      function Has_Translated_Characters return Boolean;
2095      --  return True if Item array contains a character which will be
2096      --  translated under the text file mode. There is only one such
2097      --  character under DOS based systems which is character 10.
2098
2099      text_translation_required : Boolean;
2100      for text_translation_required'Size use Character'Size;
2101      pragma Import (C, text_translation_required,
2102                     "__gnat_text_translation_required");
2103
2104      Siz : constant size_t := Item'Length;
2105
2106      -------------------------------
2107      -- Has_Translated_Characters --
2108      -------------------------------
2109
2110      function Has_Translated_Characters return Boolean is
2111      begin
2112         for K in Item'Range loop
2113            if Item (K) = 10 then
2114               return True;
2115            end if;
2116         end loop;
2117         return False;
2118      end Has_Translated_Characters;
2119
2120      Needs_Binary_Write : constant Boolean :=
2121        text_translation_required and then Has_Translated_Characters;
2122
2123   --  Start of processing for Write
2124
2125   begin
2126      if File.Mode = FCB.In_File then
2127         raise Mode_Error;
2128      end if;
2129
2130      --  Now we do the write. Since this is a text file, it is normally in
2131      --  text mode, but stream data must be written in binary mode, so we
2132      --  temporarily set binary mode for the write, resetting it after. This
2133      --  is done only if needed (i.e. there is some characters in Item which
2134      --  needs to be written using the binary mode).
2135      --  These calls have no effect in a system (like Unix) where there is
2136      --  no distinction between text and binary files.
2137
2138      --  Since the character translation is done at the time the buffer is
2139      --  written (this is true under Windows) we first flush current buffer
2140      --  with text mode if needed.
2141
2142      if Needs_Binary_Write then
2143         if fflush (File.Stream) = -1 then
2144            raise Device_Error;
2145         end if;
2146
2147         set_binary_mode (fileno (File.Stream));
2148      end if;
2149
2150      if fwrite (Item'Address, 1, Siz, File.Stream) /= Siz then
2151         raise Device_Error;
2152      end if;
2153
2154      --  At this point we need to flush the buffer using the binary mode then
2155      --  we reset to text mode.
2156
2157      if Needs_Binary_Write then
2158         if fflush (File.Stream) = -1 then
2159            raise Device_Error;
2160         end if;
2161
2162         set_text_mode (fileno (File.Stream));
2163      end if;
2164   end Write;
2165
2166begin
2167   --  Initialize Standard Files
2168
2169   for J in WC_Encoding_Method loop
2170      if WC_Encoding = WC_Encoding_Letters (J) then
2171         Default_WCEM := J;
2172      end if;
2173   end loop;
2174
2175   Initialize_Standard_Files;
2176
2177   FIO.Chain_File (AP (Standard_In));
2178   FIO.Chain_File (AP (Standard_Out));
2179   FIO.Chain_File (AP (Standard_Err));
2180
2181end Ada.Text_IO;
2182