1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . T E X T _ I O --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
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. --
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 2, 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. See the GNU General Public License --
21 -- for more details. You should have received a copy of the GNU General --
22 -- Public License distributed with GNAT; see file COPYING. If not, write --
23 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
24 -- Boston, MA 02110-1301, USA. --
26 -- As a special exception, if other files instantiate generics from this --
27 -- unit, or you link this unit with other files to produce an executable, --
28 -- this unit does not by itself cause the resulting executable to be --
29 -- covered by the GNU General Public License. This exception does not --
30 -- however invalidate any other reasons why the executable file might be --
31 -- covered by the GNU Public License. --
33 -- GNAT was originally developed by the GNAT team at New York University. --
34 -- Extensive contributions were provided by Ada Core Technologies Inc. --
36 ------------------------------------------------------------------------------
38 -- Note: the generic subpackages of Text_IO (Integer_IO, Float_IO, Fixed_IO,
39 -- Modular_IO, Decimal_IO and Enumeration_IO) appear as private children in
40 -- GNAT. These children are with'ed automatically if they are referenced, so
41 -- this rearrangement is invisible to user programs, but has the advantage
42 -- that only the needed parts of Text_IO are processed and loaded.
44 with Ada
.IO_Exceptions
;
47 with System
.File_Control_Block
;
50 package Ada
.Text_IO
is
51 pragma Elaborate_Body
;
53 type File_Type
is limited private;
54 type File_Mode
is (In_File
, Out_File
, Append_File
);
56 -- The following representation clause allows the use of unchecked
57 -- conversion for rapid translation between the File_Mode type
58 -- used in this package and System.File_IO.
61 (In_File
=> 0, -- System.FIle_IO.File_Mode'Pos (In_File)
62 Out_File
=> 2, -- System.File_IO.File_Mode'Pos (Out_File)
63 Append_File
=> 3); -- System.File_IO.File_Mode'Pos (Append_File)
65 type Count
is range 0 .. Natural'Last;
66 -- The value of Count'Last must be large enough so that the assumption
67 -- enough so that the assumption that the Line, Column and Page
68 -- counts can never exceed this value is a valid assumption.
70 subtype Positive_Count
is Count
range 1 .. Count
'Last;
72 Unbounded
: constant Count
:= 0;
73 -- Line and page length
75 subtype Field
is Integer range 0 .. 255;
76 -- Note: if for any reason, there is a need to increase this value,
77 -- then it will be necessary to change the corresponding value in
78 -- System.Img_Real in file s-imgrea.adb.
80 subtype Number_Base
is Integer range 2 .. 16;
82 type Type_Set
is (Lower_Case
, Upper_Case
);
89 (File
: in out File_Type
;
90 Mode
: File_Mode
:= Out_File
;
95 (File
: in out File_Type
;
100 procedure Close
(File
: in out File_Type
);
101 procedure Delete
(File
: in out File_Type
);
102 procedure Reset
(File
: in out File_Type
; Mode
: File_Mode
);
103 procedure Reset
(File
: in out File_Type
);
105 function Mode
(File
: File_Type
) return File_Mode
;
106 function Name
(File
: File_Type
) return String;
107 function Form
(File
: File_Type
) return String;
109 function Is_Open
(File
: File_Type
) return Boolean;
111 ------------------------------------------------------
112 -- Control of default input, output and error files --
113 ------------------------------------------------------
115 procedure Set_Input
(File
: File_Type
);
116 procedure Set_Output
(File
: File_Type
);
117 procedure Set_Error
(File
: File_Type
);
119 function Standard_Input
return File_Type
;
120 function Standard_Output
return File_Type
;
121 function Standard_Error
return File_Type
;
123 function Current_Input
return File_Type
;
124 function Current_Output
return File_Type
;
125 function Current_Error
return File_Type
;
127 type File_Access
is access constant File_Type
;
129 function Standard_Input
return File_Access
;
130 function Standard_Output
return File_Access
;
131 function Standard_Error
return File_Access
;
133 function Current_Input
return File_Access
;
134 function Current_Output
return File_Access
;
135 function Current_Error
return File_Access
;
141 -- Note: The parameter file is IN OUT in the RM, but this is clearly
142 -- an oversight, and was intended to be IN, see AI95-00057.
144 procedure Flush
(File
: File_Type
);
147 --------------------------------------------
148 -- Specification of line and page lengths --
149 --------------------------------------------
151 procedure Set_Line_Length
(File
: File_Type
; To
: Count
);
152 procedure Set_Line_Length
(To
: Count
);
154 procedure Set_Page_Length
(File
: File_Type
; To
: Count
);
155 procedure Set_Page_Length
(To
: Count
);
157 function Line_Length
(File
: File_Type
) return Count
;
158 function Line_Length
return Count
;
160 function Page_Length
(File
: File_Type
) return Count
;
161 function Page_Length
return Count
;
163 ------------------------------------
164 -- Column, Line, and Page Control --
165 ------------------------------------
167 procedure New_Line
(File
: File_Type
; Spacing
: Positive_Count
:= 1);
168 procedure New_Line
(Spacing
: Positive_Count
:= 1);
170 procedure Skip_Line
(File
: File_Type
; Spacing
: Positive_Count
:= 1);
171 procedure Skip_Line
(Spacing
: Positive_Count
:= 1);
173 function End_Of_Line
(File
: File_Type
) return Boolean;
174 function End_Of_Line
return Boolean;
176 procedure New_Page
(File
: File_Type
);
179 procedure Skip_Page
(File
: File_Type
);
182 function End_Of_Page
(File
: File_Type
) return Boolean;
183 function End_Of_Page
return Boolean;
185 function End_Of_File
(File
: File_Type
) return Boolean;
186 function End_Of_File
return Boolean;
188 procedure Set_Col
(File
: File_Type
; To
: Positive_Count
);
189 procedure Set_Col
(To
: Positive_Count
);
191 procedure Set_Line
(File
: File_Type
; To
: Positive_Count
);
192 procedure Set_Line
(To
: Positive_Count
);
194 function Col
(File
: File_Type
) return Positive_Count
;
195 function Col
return Positive_Count
;
197 function Line
(File
: File_Type
) return Positive_Count
;
198 function Line
return Positive_Count
;
200 function Page
(File
: File_Type
) return Positive_Count
;
201 function Page
return Positive_Count
;
203 ----------------------------
204 -- Character Input-Output --
205 ----------------------------
207 procedure Get
(File
: File_Type
; Item
: out Character);
208 procedure Get
(Item
: out Character);
209 procedure Put
(File
: File_Type
; Item
: Character);
210 procedure Put
(Item
: Character);
214 Item
: out Character;
215 End_Of_Line
: out Boolean);
218 (Item
: out Character;
219 End_Of_Line
: out Boolean);
221 procedure Get_Immediate
223 Item
: out Character);
225 procedure Get_Immediate
226 (Item
: out Character);
228 procedure Get_Immediate
230 Item
: out Character;
231 Available
: out Boolean);
233 procedure Get_Immediate
234 (Item
: out Character;
235 Available
: out Boolean);
237 -------------------------
238 -- String Input-Output --
239 -------------------------
241 procedure Get
(File
: File_Type
; Item
: out String);
242 procedure Get
(Item
: out String);
243 procedure Put
(File
: File_Type
; Item
: String);
244 procedure Put
(Item
: String);
255 function Get_Line
(File
: File_Type
) return String;
256 pragma Ada_05
(Get_Line
);
258 function Get_Line
return String;
259 pragma Ada_05
(Get_Line
);
268 ---------------------------------------
269 -- Generic packages for Input-Output --
270 ---------------------------------------
272 -- The generic packages:
274 -- Ada.Text_IO.Integer_IO
275 -- Ada.Text_IO.Modular_IO
276 -- Ada.Text_IO.Float_IO
277 -- Ada.Text_IO.Fixed_IO
278 -- Ada.Text_IO.Decimal_IO
279 -- Ada.Text_IO.Enumeration_IO
281 -- are implemented as separate child packages in GNAT, so the
282 -- spec and body of these packages are to be found in separate
283 -- child units. This implementation detail is hidden from the
284 -- Ada programmer by special circuitry in the compiler that
285 -- treats these child packages as though they were nested in
286 -- Text_IO. The advantage of this special processing is that
287 -- the subsidiary routines needed if these generics are used
288 -- are not loaded when they are not used.
294 Status_Error
: exception renames IO_Exceptions
.Status_Error
;
295 Mode_Error
: exception renames IO_Exceptions
.Mode_Error
;
296 Name_Error
: exception renames IO_Exceptions
.Name_Error
;
297 Use_Error
: exception renames IO_Exceptions
.Use_Error
;
298 Device_Error
: exception renames IO_Exceptions
.Device_Error
;
299 End_Error
: exception renames IO_Exceptions
.End_Error
;
300 Data_Error
: exception renames IO_Exceptions
.Data_Error
;
301 Layout_Error
: exception renames IO_Exceptions
.Layout_Error
;
304 -----------------------------------
305 -- Handling of Format Characters --
306 -----------------------------------
308 -- Line marks are represented by the single character ASCII.LF (16#0A#).
309 -- In DOS and similar systems, underlying file translation takes care
310 -- of translating this to and from the standard CR/LF sequences used in
311 -- these operating systems to mark the end of a line. On output there is
312 -- always a line mark at the end of the last line, but on input, this
313 -- line mark can be omitted, and is implied by the end of file.
315 -- Page marks are represented by the single character ASCII.FF (16#0C#),
316 -- The page mark at the end of the file may be omitted, and is normally
317 -- omitted on output unless an explicit New_Page call is made before
318 -- closing the file. No page mark is added when a file is appended to,
319 -- so, in accordance with the permission in (RM A.10.2(4)), there may
320 -- or may not be a page mark separating preexising text in the file
321 -- from the new text to be written.
323 -- A file mark is marked by the physical end of file. In DOS translation
324 -- mode on input, an EOF character (SUB = 16#1A#) gets translated to the
325 -- physical end of file, so in effect this character is recognized as
326 -- marking the end of file in DOS and similar systems.
328 LM
: constant := Character'Pos (ASCII
.LF
);
331 PM
: constant := Character'Pos (ASCII
.FF
);
332 -- Used as page mark, except at end of file where it is implied
334 --------------------------------
335 -- Text_IO File Control Block --
336 --------------------------------
338 Default_WCEM
: System
.WCh_Con
.WC_Encoding_Method
:=
339 System
.WCh_Con
.WCEM_UTF8
;
340 -- This gets modified during initialization (see body) using
341 -- the default value established in the call to Set_Globals.
343 package FCB
renames System
.File_Control_Block
;
346 type File_Type
is access all Text_AFCB
;
348 type Text_AFCB
is new FCB
.AFCB
with record
352 Line_Length
: Count
:= 0;
353 Page_Length
: Count
:= 0;
355 Self
: aliased File_Type
;
356 -- Set to point to the containing Text_AFCB block. This is used to
357 -- implement the Current_{Error,Input,Ouput} functions which return
358 -- a File_Access, the file access value returned is a pointer to
359 -- the Self field of the corresponding file.
361 Before_LM
: Boolean := False;
362 -- This flag is used to deal with the anomalies introduced by the
363 -- peculiar definition of End_Of_File and End_Of_Page in Ada. These
364 -- functions require looking ahead more than one character. Since
365 -- there is no convenient way of backing up more than one character,
366 -- what we do is to leave ourselves positioned past the LM, but set
367 -- this flag, so that we know that from an Ada point of view we are
368 -- in front of the LM, not after it. A bit of a kludge, but it works!
370 Before_LM_PM
: Boolean := False;
371 -- This flag similarly handles the case of being physically positioned
372 -- after a LM-PM sequence when logically we are before the LM-PM. This
373 -- flag can only be set if Before_LM is also set.
375 WC_Method
: System
.WCh_Con
.WC_Encoding_Method
:= Default_WCEM
;
376 -- Encoding method to be used for this file. Text_IO does not deal with
377 -- wide characters, but it does deal with upper half characters in the
378 -- range 16#80#-16#FF# which may need encoding, e.g. in UTF-8 mode.
380 Before_Upper_Half_Character
: Boolean := False;
381 -- This flag is set to indicate that an encoded upper half character has
382 -- been read by Text_IO.Look_Ahead. If it is set to True, then it means
383 -- that the stream is logically positioned before the character but is
384 -- physically positioned after it. The character involved must be in
385 -- the range 16#80#-16#FF#, i.e. if the flag is set, then we know the
386 -- next character has a code greater than 16#7F#, and the value of this
387 -- character is saved in Saved_Upper_Half_Character.
389 Saved_Upper_Half_Character
: Character;
390 -- This field is valid only if Before_Upper_Half_Character is set. It
391 -- contains an upper-half character read by Look_Ahead. If Look_Ahead
392 -- reads a character in the range 16#00# to 16#7F#, then it can use
393 -- ungetc to put it back, but ungetc cannot be called more than once,
394 -- so for characters above this range, we don't try to back up the
395 -- file. Instead we save the character in this field and set the flag
396 -- Before_Upper_Half_Character to True to indicate that we are logically
397 -- positioned before this character even though the stream is physically
398 -- positioned after it.
402 function AFCB_Allocate
(Control_Block
: Text_AFCB
) return FCB
.AFCB_Ptr
;
404 procedure AFCB_Close
(File
: not null access Text_AFCB
);
405 procedure AFCB_Free
(File
: not null access Text_AFCB
);
408 (File
: in out Text_AFCB
;
409 Item
: out Ada
.Streams
.Stream_Element_Array
;
410 Last
: out Ada
.Streams
.Stream_Element_Offset
);
411 -- Read operation used when Text_IO file is treated directly as Stream
414 (File
: in out Text_AFCB
;
415 Item
: Ada
.Streams
.Stream_Element_Array
);
416 -- Write operation used when Text_IO file is treated directly as Stream
418 ------------------------
419 -- The Standard Files --
420 ------------------------
422 Null_Str
: aliased constant String := "";
423 -- Used as name and form of standard files
425 Standard_In_AFCB
: aliased Text_AFCB
;
426 Standard_Out_AFCB
: aliased Text_AFCB
;
427 Standard_Err_AFCB
: aliased Text_AFCB
;
429 Standard_In
: aliased File_Type
:= Standard_In_AFCB
'Access;
430 Standard_Out
: aliased File_Type
:= Standard_Out_AFCB
'Access;
431 Standard_Err
: aliased File_Type
:= Standard_Err_AFCB
'Access;
434 Current_In
: aliased File_Type
:= Standard_In
;
435 Current_Out
: aliased File_Type
:= Standard_Out
;
436 Current_Err
: aliased File_Type
:= Standard_Err
;
439 -----------------------
440 -- Local Subprograms --
441 -----------------------
443 -- These subprograms are in the private part of the spec so that they can
444 -- be shared by the routines in the body of Ada.Text_IO.Wide_Text_IO.
446 -- Note: we use Integer in these declarations instead of the more accurate
447 -- Interfaces.C_Streams.int, because we do not want to drag in the spec of
448 -- this interfaces package with the spec of Ada.Text_IO, and we know that
449 -- in fact these types are identical
451 function EOF_Char
return Integer;
452 -- Returns the system-specific character indicating the end of a text file.
453 -- This is exported for use by child packages such as Enumeration_Aux to
454 -- eliminate their needing to depend directly on Interfaces.C_Streams.
456 function Getc
(File
: File_Type
) return Integer;
457 -- Gets next character from file, which has already been checked for
458 -- being in read status, and returns the character read if no error
459 -- occurs. The result is EOF if the end of file was read.
461 function Nextc
(File
: File_Type
) return Integer;
462 -- Returns next character from file without skipping past it (i.e. it
463 -- is a combination of Getc followed by an Ungetc).
465 procedure Putc
(ch
: Integer; File
: File_Type
);
466 -- Outputs the given character to the file, which has already been
467 -- checked for being in output status. Device_Error is raised if the
468 -- character cannot be written.
470 procedure Terminate_Line
(File
: File_Type
);
471 -- If the file is in Write_File or Append_File mode, and the current
472 -- line is not terminated, then a line terminator is written using
473 -- New_Line. Note that there is no Terminate_Page routine, because
474 -- the page mark at the end of the file is implied if necessary.
476 procedure Ungetc
(ch
: Integer; File
: File_Type
);
477 -- Pushes back character into stream, using ungetc. The caller has
478 -- checked that the file is in read status. Device_Error is raised
479 -- if the character cannot be pushed back. An attempt to push back
480 -- and end of file character (EOF) is ignored.