File : a-textio.ads
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) 1992-2014, 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 -- --
23 -- --
24 -- --
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
42 with Ada.IO_Exceptions;
43 with Ada.Streams;
44
45 with System;
46 with System.File_Control_Block;
47 with System.WCh_Con;
48
49 package Ada.Text_IO is
50 pragma Elaborate_Body;
51
52 type File_Type is limited private;
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
301 private
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
471 end Ada.Text_IO;