gcc/ada/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 --                            $Revision: 1.51 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- This specification is derived from the Ada Reference Manual for use with --
  14 -- GNAT. The copyright notice above, and the license provisions that follow --
  15 -- apply solely to the  contents of the part following the private keyword. --
  16 --                                                                          --
  17 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  18 -- terms of the  GNU General Public License as published  by the Free Soft- --
  19 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  20 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  21 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  22 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  23 -- for  more details.  You should have  received  a copy of the GNU General --
  24 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  25 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  26 -- MA 02111-1307, USA.                                                      --
  27 --                                                                          --
  28 -- As a special exception,  if other files  instantiate  generics from this --
  29 -- unit, or you link  this unit with other files  to produce an executable, --
  30 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  31 -- covered  by the  GNU  General  Public  License.  This exception does not --
  32 -- however invalidate  any other reasons why  the executable file  might be --
  33 -- covered by the  GNU Public License.                                      --
  34 --                                                                          --
  35 -- GNAT was originally developed  by the GNAT team at  New York University. --
  36 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  37 --                                                                          --
  38 ------------------------------------------------------------------------------
  39
  40 --  Note: the generic subpackages of Text_IO (Integer_IO, Float_IO, Fixed_IO,
  41 --  Modular_IO, Decimal_IO and Enumeration_IO) appear as private children in
  42 --  GNAT. These children are with'ed automatically if they are referenced, so
  43 --  this rearrangement is invisible to user programs, but has the advantage
  44 --  that only the needed parts of Text_IO are processed and loaded.
  45
  46 with Ada.IO_Exceptions;
  47 with Ada.Streams;
  48 with System;
  49 with System.File_Control_Block;
  50
  51 package Ada.Text_IO is
  52 pragma Elaborate_Body (Text_IO);
  53
  54    type File_Type is limited private;
  55    type File_Mode is (In_File, Out_File, Append_File);
  56
  57    --  The following representation clause allows the use of unchecked
  58    --  conversion for rapid translation between the File_Mode type
  59    --  used in this package and System.File_IO.
  60
  61    for File_Mode use
  62      (In_File     => 0,  -- System.FIle_IO.File_Mode'Pos (In_File)
  63       Out_File    => 2,  -- System.File_IO.File_Mode'Pos (Out_File)
  64       Append_File => 3); -- System.File_IO.File_Mode'Pos (Append_File)
  65
  66    type Count is range 0 .. Natural'Last;
  67    --  The value of Count'Last must be large enough so that the assumption
  68    --  enough so that the assumption that the Line, Column and Page
  69    --  counts can never exceed this value is a valid assumption.
  70
  71    subtype Positive_Count is Count range 1 .. Count'Last;
  72
  73    Unbounded : constant Count := 0;
  74    --  Line and page length
  75
  76    subtype Field is Integer range 0 .. 255;
  77    --  Note: if for any reason, there is a need to increase this value,
  78    --  then it will be necessary to change the corresponding value in
  79    --  System.Img_Real in file s-imgrea.adb.
  80
  81    subtype Number_Base is Integer range 2 .. 16;
  82
  83    type Type_Set is (Lower_Case, Upper_Case);
  84
  85    ---------------------
  86    -- File Management --
  87    ---------------------
  88
  89    procedure Create
  90      (File : in out File_Type;
  91       Mode : in File_Mode := Out_File;
  92       Name : in String := "";
  93       Form : in String := "");
  94
  95    procedure Open
  96      (File : in out File_Type;
  97       Mode : in File_Mode;
  98       Name : in String;
  99       Form : in String := "");
 100
 101    procedure Close  (File : in out File_Type);
 102    procedure Delete (File : in out File_Type);
 103    procedure Reset  (File : in out File_Type; Mode : in File_Mode);
 104    procedure Reset  (File : in out File_Type);
 105
 106    function Mode (File : in File_Type) return File_Mode;
 107    function Name (File : in File_Type) return String;
 108    function Form (File : in File_Type) return String;
 109
 110    function Is_Open (File : in File_Type) return Boolean;
 111
 112    ------------------------------------------------------
 113    -- Control of default input, output and error files --
 114    ------------------------------------------------------
 115
 116    procedure Set_Input  (File : in File_Type);
 117    procedure Set_Output (File : in File_Type);
 118    procedure Set_Error  (File : in File_Type);
 119
 120    function Standard_Input  return File_Type;
 121    function Standard_Output return File_Type;
 122    function Standard_Error  return File_Type;
 123
 124    function Current_Input  return File_Type;
 125    function Current_Output return File_Type;
 126    function Current_Error  return File_Type;
 127
 128    type File_Access is access constant File_Type;
 129
 130    function Standard_Input  return File_Access;
 131    function Standard_Output return File_Access;
 132    function Standard_Error  return File_Access;
 133
 134    function Current_Input  return File_Access;
 135    function Current_Output return File_Access;
 136    function Current_Error  return File_Access;
 137
 138    --------------------
 139    -- Buffer control --
 140    --------------------
 141
 142    --  Note: The parameter file is IN OUT in the RM, but this is clearly
 143    --  an oversight, and was intended to be IN, see AI95-00057.
 144
 145    procedure Flush (File : in File_Type);
 146    procedure Flush;
 147
 148    --------------------------------------------
 149    -- Specification of line and page lengths --
 150    --------------------------------------------
 151
 152    procedure Set_Line_Length (File : in File_Type; To : in Count);
 153    procedure Set_Line_Length (To : in Count);
 154
 155    procedure Set_Page_Length (File : in File_Type; To : in Count);
 156    procedure Set_Page_Length (To : in Count);
 157
 158    function Line_Length (File : in File_Type) return Count;
 159    function Line_Length return Count;
 160
 161    function Page_Length (File : in File_Type) return Count;
 162    function Page_Length return Count;
 163
 164    ------------------------------------
 165    -- Column, Line, and Page Control --
 166    ------------------------------------
 167
 168    procedure New_Line (File : in File_Type; Spacing : in Positive_Count := 1);
 169    procedure New_Line (Spacing : in Positive_Count := 1);
 170
 171    procedure Skip_Line (File : in File_Type; Spacing : in Positive_Count := 1);
 172    procedure Skip_Line (Spacing : in Positive_Count := 1);
 173
 174    function End_Of_Line (File : in File_Type) return Boolean;
 175    function End_Of_Line return Boolean;
 176
 177    procedure New_Page (File : in File_Type);
 178    procedure New_Page;
 179
 180    procedure Skip_Page (File : in File_Type);
 181    procedure Skip_Page;
 182
 183    function End_Of_Page (File : in File_Type) return Boolean;
 184    function End_Of_Page return Boolean;
 185
 186    function End_Of_File (File : in File_Type) return Boolean;
 187    function End_Of_File return Boolean;
 188
 189    procedure Set_Col (File : in File_Type;  To : in Positive_Count);
 190    procedure Set_Col (To : in Positive_Count);
 191
 192    procedure Set_Line (File : in File_Type; To : in Positive_Count);
 193    procedure Set_Line (To : in Positive_Count);
 194
 195    function Col (File : in File_Type) return Positive_Count;
 196    function Col return Positive_Count;
 197
 198    function Line (File : in File_Type) return Positive_Count;
 199    function Line return Positive_Count;
 200
 201    function Page (File : in File_Type) return Positive_Count;
 202    function Page return Positive_Count;
 203
 204    ----------------------------
 205    -- Character Input-Output --
 206    ----------------------------
 207
 208    procedure Get (File : in File_Type; Item : out Character);
 209    procedure Get (Item : out Character);
 210    procedure Put (File : in File_Type; Item : in Character);
 211    procedure Put (Item : in Character);
 212
 213    procedure Look_Ahead
 214      (File        : in File_Type;
 215       Item        : out Character;
 216       End_Of_Line : out Boolean);
 217
 218    procedure Look_Ahead
 219      (Item        : out Character;
 220       End_Of_Line : out Boolean);
 221
 222    procedure Get_Immediate
 223      (File : in File_Type;
 224       Item : out Character);
 225
 226    procedure Get_Immediate
 227      (Item : out Character);
 228
 229    procedure Get_Immediate
 230      (File      : in File_Type;
 231       Item      : out Character;
 232       Available : out Boolean);
 233
 234    procedure Get_Immediate
 235      (Item      : out Character;
 236       Available : out Boolean);
 237
 238    -------------------------
 239    -- String Input-Output --
 240    -------------------------
 241
 242    procedure Get (File : in File_Type; Item : out String);
 243    procedure Get (Item : out String);
 244    procedure Put (File : in File_Type; Item : in String);
 245    procedure Put (Item : in String);
 246
 247    procedure Get_Line
 248      (File : in File_Type;
 249       Item : out String;
 250       Last : out Natural);
 251
 252    procedure Get_Line
 253      (Item : out String;
 254       Last : out Natural);
 255
 256    procedure Put_Line
 257      (File : in File_Type;
 258       Item : in String);
 259
 260    procedure Put_Line
 261      (Item : in String);
 262
 263    ---------------------------------------
 264    -- Generic packages for Input-Output --
 265    ---------------------------------------
 266
 267    --  The generic packages:
 268
 269    --    Ada.Text_IO.Integer_IO
 270    --    Ada.Text_IO.Modular_IO
 271    --    Ada.Text_IO.Float_IO
 272    --    Ada.Text_IO.Fixed_IO
 273    --    Ada.Text_IO.Decimal_IO
 274    --    Ada.Text_IO.Enumeration_IO
 275
 276    --  are implemented as separate child packages in GNAT, so the
 277    --  spec and body of these packages are to be found in separate
 278    --  child units. This implementation detail is hidden from the
 279    --  Ada programmer by special circuitry in the compiler that
 280    --  treats these child packages as though they were nested in
 281    --  Text_IO. The advantage of this special processing is that
 282    --  the subsidiary routines needed if these generics are used
 283    --  are not loaded when they are not used.
 284
 285    ----------------
 286    -- Exceptions --
 287    ----------------
 288
 289    Status_Error : exception renames IO_Exceptions.Status_Error;
 290    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 291    Name_Error   : exception renames IO_Exceptions.Name_Error;
 292    Use_Error    : exception renames IO_Exceptions.Use_Error;
 293    Device_Error : exception renames IO_Exceptions.Device_Error;
 294    End_Error    : exception renames IO_Exceptions.End_Error;
 295    Data_Error   : exception renames IO_Exceptions.Data_Error;
 296    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 297
 298 private
 299    -----------------------------------
 300    -- Handling of Format Characters --
 301    -----------------------------------
 302
 303    --  Line marks are represented by the single character ASCII.LF (16#0A#).
 304    --  In DOS and similar systems, underlying file translation takes care
 305    --  of translating this to and from the standard CR/LF sequences used in
 306    --  these operating systems to mark the end of a line. On output there is
 307    --  always a line mark at the end of the last line, but on input, this
 308    --  line mark can be omitted, and is implied by the end of file.
 309
 310    --  Page marks are represented by the single character ASCII.FF (16#0C#),
 311    --  The page mark at the end of the file may be omitted, and is normally
 312    --  omitted on output unless an explicit New_Page call is made before
 313    --  closing the file. No page mark is added when a file is appended to,
 314    --  so, in accordance with the permission in (RM A.10.2(4)), there may
 315    --  or may not be a page mark separating preexising text in the file
 316    --  from the new text to be written.
 317
 318    --  A file mark is marked by the physical end of file. In DOS translation
 319    --  mode on input, an EOF character (SUB = 16#1A#) gets translated to the
 320    --  physical end of file, so in effect this character is recognized as
 321    --  marking the end of file in DOS and similar systems.
 322
 323    LM : constant := Character'Pos (ASCII.LF);
 324    --  Used as line mark
 325
 326    PM : constant := Character'Pos (ASCII.FF);
 327    --  Used as page mark, except at end of file where it is implied
 328
 329    --------------------------------
 330    -- Text_IO File Control Block --
 331    --------------------------------
 332
 333    package FCB renames System.File_Control_Block;
 334
 335    type Text_AFCB;
 336    type File_Type is access all Text_AFCB;
 337
 338    type Text_AFCB is new FCB.AFCB with record
 339       Page        : Count := 1;
 340       Line        : Count := 1;
 341       Col         : Count := 1;
 342       Line_Length : Count := 0;
 343       Page_Length : Count := 0;
 344
 345       Self : aliased File_Type;
 346       --  Set to point to the containing Text_AFCB block. This is used to
 347       --  implement the Current_{Error,Input,Ouput} functions which return
 348       --  a File_Access, the file access value returned is a pointer to
 349       --  the Self field of the corresponding file.
 350
 351       Before_LM : Boolean := False;
 352       --  This flag is used to deal with the anomolies introduced by the
 353       --  peculiar definition of End_Of_File and End_Of_Page in Ada. These
 354       --  functions require looking ahead more than one character. Since
 355       --  there is no convenient way of backing up more than one character,
 356       --  what we do is to leave ourselves positioned past the LM, but set
 357       --  this flag, so that we know that from an Ada point of view we are
 358       --  in front of the LM, not after it. A bit of a kludge, but it works!
 359
 360       Before_LM_PM : Boolean := False;
 361       --  This flag similarly handles the case of being physically positioned
 362       --  after a LM-PM sequence when logically we are before the LM-PM. This
 363       --  flag can only be set if Before_LM is also set.
 364
 365    end record;
 366
 367    function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
 368
 369    procedure AFCB_Close (File : access Text_AFCB);
 370    procedure AFCB_Free  (File : access Text_AFCB);
 371
 372    procedure Read
 373      (File : in out Text_AFCB;
 374       Item : out Ada.Streams.Stream_Element_Array;
 375       Last : out Ada.Streams.Stream_Element_Offset);
 376    --  Read operation used when Text_IO file is treated directly as Stream
 377
 378    procedure Write
 379      (File : in out Text_AFCB;
 380       Item : in Ada.Streams.Stream_Element_Array);
 381    --  Write operation used when Text_IO file is treated directly as Stream
 382
 383    ------------------------
 384    -- The Standard Files --
 385    ------------------------
 386
 387    Null_Str : aliased constant String := "";
 388    --  Used as name and form of standard files
 389
 390    Standard_Err_AFCB : aliased Text_AFCB;
 391    Standard_In_AFCB  : aliased Text_AFCB;
 392    Standard_Out_AFCB : aliased Text_AFCB;
 393
 394    Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
 395    Standard_In  : aliased File_Type := Standard_In_AFCB'Access;
 396    Standard_Out : aliased File_Type := Standard_Out_AFCB'Access;
 397    --  Standard files
 398
 399    Current_In   : aliased File_Type := Standard_In;
 400    Current_Out  : aliased File_Type := Standard_Out;
 401    Current_Err  : aliased File_Type := Standard_Err;
 402    --  Current files
 403
 404    -----------------------
 405    -- Local Subprograms --
 406    -----------------------
 407
 408    --  These subprograms are in the private part of the spec so that they can
 409    --  be shared by the routines in the body of Ada.Text_IO.Wide_Text_IO.
 410
 411    --  Note: we use Integer in these declarations instead of the more accurate
 412    --  Interfaces.C_Streams.int, because we do not want to drag in the spec of
 413    --  this interfaces package with the spec of Ada.Text_IO, and we know that
 414    --  in fact these types are identical
 415
 416    function Getc (File : File_Type) return Integer;
 417    --  Gets next character from file, which has already been checked for
 418    --  being in read status, and returns the character read if no error
 419    --  occurs. The result is EOF if the end of file was read.
 420
 421    function Nextc (File : File_Type) return Integer;
 422    --  Returns next character from file without skipping past it (i.e. it
 423    --  is a combination of Getc followed by an Ungetc).
 424
 425    procedure Putc (ch : Integer; File : File_Type);
 426    --  Outputs the given character to the file, which has already been
 427    --  checked for being in output status. Device_Error is raised if the
 428    --  character cannot be written.
 429
 430    procedure Terminate_Line (File : File_Type);
 431    --  If the file is in Write_File or Append_File mode, and the current
 432    --  line is not terminated, then a line terminator is written using
 433    --  New_Line. Note that there is no Terminate_Page routine, because
 434    --  the page mark at the end of the file is implied if necessary.
 435
 436    procedure Ungetc (ch : Integer; File : File_Type);
 437    --  Pushes back character into stream, using ungetc. The caller has
 438    --  checked that the file is in read status. Device_Error is raised
 439    --  if the character cannot be pushed back. An attempt to push back
 440    --  and end of file character (EOF) is ignored.
 441
 442 end Ada.Text_IO;