1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                          A D A . T E X T _ I O                           --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2019, Free Software Foundation, Inc.         --
10--                                                                          --
11-- This specification is derived from the Ada Reference Manual for use with --
12-- GNAT. The copyright notice above, and the license provisions that follow --
13-- apply solely to the  contents of the part following the private keyword. --
14--                                                                          --
15-- GNAT is free software;  you can  redistribute it  and/or modify it under --
16-- terms of the  GNU General Public License as published  by the Free Soft- --
17-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
18-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
19-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
20-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
21--                                                                          --
22-- As a special exception under Section 7 of GPL version 3, you are granted --
23-- additional permissions described in the GCC Runtime Library Exception,   --
24-- version 3.1, as published by the Free Software Foundation.               --
25--                                                                          --
26-- You should have received a copy of the GNU General Public License and    --
27-- a copy of the GCC Runtime Library Exception along with this program;     --
28-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
29-- <http://www.gnu.org/licenses/>.                                          --
30--                                                                          --
31-- GNAT was originally developed  by the GNAT team at  New York University. --
32-- Extensive contributions were provided by Ada Core Technologies Inc.      --
33--                                                                          --
34------------------------------------------------------------------------------
35
36--  Note: the generic subpackages of Text_IO (Integer_IO, Float_IO, Fixed_IO,
37--  Modular_IO, Decimal_IO and Enumeration_IO) appear as private children in
38--  GNAT. These children are with'ed automatically if they are referenced, so
39--  this rearrangement is invisible to user programs, but has the advantage
40--  that only the needed parts of Text_IO are processed and loaded.
41
42with Ada.IO_Exceptions;
43with Ada.Streams;
44
45with System;
46with System.File_Control_Block;
47with System.WCh_Con;
48
49package Ada.Text_IO is
50   pragma Elaborate_Body;
51
52   type File_Type is limited private with Default_Initial_Condition;
53   type File_Mode is (In_File, Out_File, Append_File);
54
55   --  The following representation clause allows the use of unchecked
56   --  conversion for rapid translation between the File_Mode type
57   --  used in this package and System.File_IO.
58
59   for File_Mode use
60     (In_File     => 0,  -- System.FIle_IO.File_Mode'Pos (In_File)
61      Out_File    => 2,  -- System.File_IO.File_Mode'Pos (Out_File)
62      Append_File => 3); -- System.File_IO.File_Mode'Pos (Append_File)
63
64   type Count is range 0 .. Natural'Last;
65   --  The value of Count'Last must be large enough so that the assumption that
66   --  the Line, Column and Page counts can never exceed this value is valid.
67
68   subtype Positive_Count is Count range 1 .. Count'Last;
69
70   Unbounded : constant Count := 0;
71   --  Line and page length
72
73   subtype Field is Integer range 0 .. 255;
74   --  Note: if for any reason, there is a need to increase this value, then it
75   --  will be necessary to change the corresponding value in System.Img_Real
76   --  in file s-imgrea.adb.
77
78   subtype Number_Base is Integer range 2 .. 16;
79
80   type Type_Set is (Lower_Case, Upper_Case);
81
82   ---------------------
83   -- File Management --
84   ---------------------
85
86   procedure Create
87     (File : in out File_Type;
88      Mode : File_Mode := Out_File;
89      Name : String := "";
90      Form : String := "");
91
92   procedure Open
93     (File : in out File_Type;
94      Mode : File_Mode;
95      Name : String;
96      Form : String := "");
97
98   procedure Close  (File : in out File_Type);
99   procedure Delete (File : in out File_Type);
100   procedure Reset  (File : in out File_Type; Mode : File_Mode);
101   procedure Reset  (File : in out File_Type);
102
103   function Mode (File : File_Type) return File_Mode;
104   function Name (File : File_Type) return String;
105   function Form (File : File_Type) return String;
106
107   function Is_Open (File : File_Type) return Boolean;
108
109   ------------------------------------------------------
110   -- Control of default input, output and error files --
111   ------------------------------------------------------
112
113   procedure Set_Input  (File : File_Type);
114   procedure Set_Output (File : File_Type);
115   procedure Set_Error  (File : File_Type);
116
117   function Standard_Input  return File_Type;
118   function Standard_Output return File_Type;
119   function Standard_Error  return File_Type;
120
121   function Current_Input  return File_Type;
122   function Current_Output return File_Type;
123   function Current_Error  return File_Type;
124
125   type File_Access is access constant File_Type;
126
127   function Standard_Input  return File_Access;
128   function Standard_Output return File_Access;
129   function Standard_Error  return File_Access;
130
131   function Current_Input  return File_Access;
132   function Current_Output return File_Access;
133   function Current_Error  return File_Access;
134
135   --------------------
136   -- Buffer control --
137   --------------------
138
139   --  Note: The parameter file is IN OUT in the RM, but this is clearly
140   --  an oversight, and was intended to be IN, see AI95-00057.
141
142   procedure Flush (File : File_Type);
143   procedure Flush;
144
145   --------------------------------------------
146   -- Specification of line and page lengths --
147   --------------------------------------------
148
149   procedure Set_Line_Length (File : File_Type; To : Count);
150   procedure Set_Line_Length (To : Count);
151
152   procedure Set_Page_Length (File : File_Type; To : Count);
153   procedure Set_Page_Length (To : Count);
154
155   function Line_Length (File : File_Type) return Count;
156   function Line_Length return Count;
157
158   function Page_Length (File : File_Type) return Count;
159   function Page_Length return Count;
160
161   ------------------------------------
162   -- Column, Line, and Page Control --
163   ------------------------------------
164
165   procedure New_Line (File : File_Type; Spacing : Positive_Count := 1);
166   procedure New_Line (Spacing : Positive_Count := 1);
167
168   procedure Skip_Line (File : File_Type; Spacing : Positive_Count := 1);
169   procedure Skip_Line (Spacing : Positive_Count := 1);
170
171   function End_Of_Line (File : File_Type) return Boolean;
172   function End_Of_Line return Boolean;
173
174   procedure New_Page (File : File_Type);
175   procedure New_Page;
176
177   procedure Skip_Page (File : File_Type);
178   procedure Skip_Page;
179
180   function End_Of_Page (File : File_Type) return Boolean;
181   function End_Of_Page return Boolean;
182
183   function End_Of_File (File : File_Type) return Boolean;
184   function End_Of_File return Boolean;
185
186   procedure Set_Col (File : File_Type;  To : Positive_Count);
187   procedure Set_Col (To : Positive_Count);
188
189   procedure Set_Line (File : File_Type; To : Positive_Count);
190   procedure Set_Line (To : Positive_Count);
191
192   function Col (File : File_Type) return Positive_Count;
193   function Col return Positive_Count;
194
195   function Line (File : File_Type) return Positive_Count;
196   function Line return Positive_Count;
197
198   function Page (File : File_Type) return Positive_Count;
199   function Page return Positive_Count;
200
201   ----------------------------
202   -- Character Input-Output --
203   ----------------------------
204
205   procedure Get (File : File_Type; Item : out Character);
206   procedure Get (Item : out Character);
207   procedure Put (File : File_Type; Item : Character);
208   procedure Put (Item : Character);
209
210   procedure Look_Ahead
211     (File        : File_Type;
212      Item        : out Character;
213      End_Of_Line : out Boolean);
214
215   procedure Look_Ahead
216     (Item        : out Character;
217      End_Of_Line : out Boolean);
218
219   procedure Get_Immediate
220     (File : File_Type;
221      Item : out Character);
222
223   procedure Get_Immediate
224     (Item : out Character);
225
226   procedure Get_Immediate
227     (File      : File_Type;
228      Item      : out Character;
229      Available : out Boolean);
230
231   procedure Get_Immediate
232     (Item      : out Character;
233      Available : out Boolean);
234
235   -------------------------
236   -- String Input-Output --
237   -------------------------
238
239   procedure Get (File : File_Type; Item : out String);
240   procedure Get (Item : out String);
241   procedure Put (File : File_Type; Item : String);
242   procedure Put (Item : String);
243
244   procedure Get_Line
245     (File : File_Type;
246      Item : out String;
247      Last : out Natural);
248
249   procedure Get_Line
250     (Item : out String;
251      Last : out Natural);
252
253   function Get_Line (File : File_Type) return String;
254   pragma Ada_05 (Get_Line);
255
256   function Get_Line return String;
257   pragma Ada_05 (Get_Line);
258
259   procedure Put_Line
260     (File : File_Type;
261      Item : String);
262
263   procedure Put_Line
264     (Item : String);
265
266   ---------------------------------------
267   -- Generic packages for Input-Output --
268   ---------------------------------------
269
270   --  The generic packages:
271
272   --    Ada.Text_IO.Integer_IO
273   --    Ada.Text_IO.Modular_IO
274   --    Ada.Text_IO.Float_IO
275   --    Ada.Text_IO.Fixed_IO
276   --    Ada.Text_IO.Decimal_IO
277   --    Ada.Text_IO.Enumeration_IO
278
279   --  are implemented as separate child packages in GNAT, so the
280   --  spec and body of these packages are to be found in separate
281   --  child units. This implementation detail is hidden from the
282   --  Ada programmer by special circuitry in the compiler that
283   --  treats these child packages as though they were nested in
284   --  Text_IO. The advantage of this special processing is that
285   --  the subsidiary routines needed if these generics are used
286   --  are not loaded when they are not used.
287
288   ----------------
289   -- Exceptions --
290   ----------------
291
292   Status_Error : exception renames IO_Exceptions.Status_Error;
293   Mode_Error   : exception renames IO_Exceptions.Mode_Error;
294   Name_Error   : exception renames IO_Exceptions.Name_Error;
295   Use_Error    : exception renames IO_Exceptions.Use_Error;
296   Device_Error : exception renames IO_Exceptions.Device_Error;
297   End_Error    : exception renames IO_Exceptions.End_Error;
298   Data_Error   : exception renames IO_Exceptions.Data_Error;
299   Layout_Error : exception renames IO_Exceptions.Layout_Error;
300
301private
302
303   --  The following procedures have a File_Type formal of mode IN OUT because
304   --  they may close the original file. The Close operation may raise an
305   --  exception, but in that case we want any assignment to the formal to
306   --  be effective anyway, so it must be passed by reference (or the caller
307   --  will be left with a dangling pointer).
308
309   pragma Export_Procedure
310     (Internal  => Close,
311      External  => "",
312      Mechanism => Reference);
313   pragma Export_Procedure
314     (Internal  => Delete,
315      External  => "",
316      Mechanism => Reference);
317   pragma Export_Procedure
318     (Internal        => Reset,
319      External        => "",
320      Parameter_Types => (File_Type),
321      Mechanism       => Reference);
322   pragma Export_Procedure
323     (Internal        => Reset,
324      External        => "",
325      Parameter_Types => (File_Type, File_Mode),
326      Mechanism       => (File => Reference));
327
328   -----------------------------------
329   -- Handling of Format Characters --
330   -----------------------------------
331
332   --  Line marks are represented by the single character ASCII.LF (16#0A#).
333   --  In DOS and similar systems, underlying file translation takes care
334   --  of translating this to and from the standard CR/LF sequences used in
335   --  these operating systems to mark the end of a line. On output there is
336   --  always a line mark at the end of the last line, but on input, this
337   --  line mark can be omitted, and is implied by the end of file.
338
339   --  Page marks are represented by the single character ASCII.FF (16#0C#),
340   --  The page mark at the end of the file may be omitted, and is normally
341   --  omitted on output unless an explicit New_Page call is made before
342   --  closing the file. No page mark is added when a file is appended to,
343   --  so, in accordance with the permission in (RM A.10.2(4)), there may
344   --  or may not be a page mark separating preexisting text in the file
345   --  from the new text to be written.
346
347   --  A file mark is marked by the physical end of file. In DOS translation
348   --  mode on input, an EOF character (SUB = 16#1A#) gets translated to the
349   --  physical end of file, so in effect this character is recognized as
350   --  marking the end of file in DOS and similar systems.
351
352   LM : constant := Character'Pos (ASCII.LF);
353   --  Used as line mark
354
355   PM : constant := Character'Pos (ASCII.FF);
356   --  Used as page mark, except at end of file where it is implied
357
358   --------------------------------
359   -- Text_IO File Control Block --
360   --------------------------------
361
362   Default_WCEM : System.WCh_Con.WC_Encoding_Method :=
363                    System.WCh_Con.WCEM_UTF8;
364   --  This gets modified during initialization (see body) using
365   --  the default value established in the call to Set_Globals.
366
367   package FCB renames System.File_Control_Block;
368
369   type Text_AFCB;
370   type File_Type is access all Text_AFCB;
371
372   type Text_AFCB is new FCB.AFCB with record
373      Page        : Count := 1;
374      Line        : Count := 1;
375      Col         : Count := 1;
376      Line_Length : Count := 0;
377      Page_Length : Count := 0;
378
379      Self : aliased File_Type;
380      --  Set to point to the containing Text_AFCB block. This is used to
381      --  implement the Current_{Error,Input,Output} functions which return
382      --  a File_Access, the file access value returned is a pointer to
383      --  the Self field of the corresponding file.
384
385      Before_LM : Boolean := False;
386      --  This flag is used to deal with the anomalies introduced by the
387      --  peculiar definition of End_Of_File and End_Of_Page in Ada. These
388      --  functions require looking ahead more than one character. Since
389      --  there is no convenient way of backing up more than one character,
390      --  what we do is to leave ourselves positioned past the LM, but set
391      --  this flag, so that we know that from an Ada point of view we are
392      --  in front of the LM, not after it. A little odd, but it works.
393
394      Before_LM_PM : Boolean := False;
395      --  This flag similarly handles the case of being physically positioned
396      --  after a LM-PM sequence when logically we are before the LM-PM. This
397      --  flag can only be set if Before_LM is also set.
398
399      WC_Method : System.WCh_Con.WC_Encoding_Method := Default_WCEM;
400      --  Encoding method to be used for this file. Text_IO does not deal with
401      --  wide characters, but it does deal with upper half characters in the
402      --  range 16#80#-16#FF# which may need encoding, e.g. in UTF-8 mode.
403
404      Before_Upper_Half_Character : Boolean := False;
405      --  This flag is set to indicate that an encoded upper half character has
406      --  been read by Text_IO.Look_Ahead. If it is set to True, then it means
407      --  that the stream is logically positioned before the character but is
408      --  physically positioned after it. The character involved must be in
409      --  the range 16#80#-16#FF#, i.e. if the flag is set, then we know the
410      --  next character has a code greater than 16#7F#, and the value of this
411      --  character is saved in Saved_Upper_Half_Character.
412
413      Saved_Upper_Half_Character : Character;
414      --  This field is valid only if Before_Upper_Half_Character is set. It
415      --  contains an upper-half character read by Look_Ahead. If Look_Ahead
416      --  reads a character in the range 16#00# to 16#7F#, then it can use
417      --  ungetc to put it back, but ungetc cannot be called more than once,
418      --  so for characters above this range, we don't try to back up the
419      --  file. Instead we save the character in this field and set the flag
420      --  Before_Upper_Half_Character to True to indicate that we are logically
421      --  positioned before this character even though the stream is physically
422      --  positioned after it.
423
424   end record;
425
426   function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
427
428   procedure AFCB_Close (File : not null access Text_AFCB);
429   procedure AFCB_Free  (File : not null access Text_AFCB);
430
431   procedure Read
432     (File : in out Text_AFCB;
433      Item : out Ada.Streams.Stream_Element_Array;
434      Last : out Ada.Streams.Stream_Element_Offset);
435   --  Read operation used when Text_IO file is treated directly as Stream
436
437   procedure Write
438     (File : in out Text_AFCB;
439      Item : Ada.Streams.Stream_Element_Array);
440   --  Write operation used when Text_IO file is treated directly as Stream
441
442   ------------------------
443   -- The Standard Files --
444   ------------------------
445
446   Standard_In_AFCB  : aliased Text_AFCB;
447   Standard_Out_AFCB : aliased Text_AFCB;
448   Standard_Err_AFCB : aliased Text_AFCB;
449
450   Standard_In  : aliased File_Type := Standard_In_AFCB'Access;
451   Standard_Out : aliased File_Type := Standard_Out_AFCB'Access;
452   Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
453   --  Standard files
454
455   Current_In   : aliased File_Type := Standard_In;
456   Current_Out  : aliased File_Type := Standard_Out;
457   Current_Err  : aliased File_Type := Standard_Err;
458   --  Current files
459
460   function EOF_Char return Integer;
461   --  Returns the system-specific character indicating the end of a text file.
462   --  This is exported for use by child packages such as Enumeration_Aux to
463   --  eliminate their needing to depend directly on Interfaces.C_Streams,
464   --  which is not available in certain target environments (such as AAMP).
465
466   procedure Initialize_Standard_Files;
467   --  Initializes the file control blocks for the standard files. Called from
468   --  the elaboration routine for this package, and from Reset_Standard_Files
469   --  in package Ada.Text_IO.Reset_Standard_Files.
470
471end Ada.Text_IO;
472