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 --          Copyright (C) 1992-2002 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 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,  59 Temple Place - Suite 330,  Boston, --
  24 -- MA 02111-1307, USA.                                                      --
  25 --                                                                          --
  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.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  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.
  43
  44 with Ada.IO_Exceptions;
  45 with Ada.Streams;
  46 with System;
  47 with System.File_Control_Block;
  48
  49 package Ada.Text_IO is
  50 pragma Elaborate_Body (Text_IO);
  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
  66    --  enough so that the assumption that the Line, Column and Page
  67    --  counts can never exceed this value is a valid assumption.
  68
  69    subtype Positive_Count is Count range 1 .. Count'Last;
  70
  71    Unbounded : constant Count := 0;
  72    --  Line and page length
  73
  74    subtype Field is Integer range 0 .. 255;
  75    --  Note: if for any reason, there is a need to increase this value,
  76    --  then it will be necessary to change the corresponding value in
  77    --  System.Img_Real in file s-imgrea.adb.
  78
  79    subtype Number_Base is Integer range 2 .. 16;
  80
  81    type Type_Set is (Lower_Case, Upper_Case);
  82
  83    ---------------------
  84    -- File Management --
  85    ---------------------
  86
  87    procedure Create
  88      (File : in out File_Type;
  89       Mode : in File_Mode := Out_File;
  90       Name : in String := "";
  91       Form : in String := "");
  92
  93    procedure Open
  94      (File : in out File_Type;
  95       Mode : in File_Mode;
  96       Name : in String;
  97       Form : in String := "");
  98
  99    procedure Close  (File : in out File_Type);
 100    procedure Delete (File : in out File_Type);
 101    procedure Reset  (File : in out File_Type; Mode : in File_Mode);
 102    procedure Reset  (File : in out File_Type);
 103
 104    function Mode (File : in File_Type) return File_Mode;
 105    function Name (File : in File_Type) return String;
 106    function Form (File : in File_Type) return String;
 107
 108    function Is_Open (File : in File_Type) return Boolean;
 109
 110    ------------------------------------------------------
 111    -- Control of default input, output and error files --
 112    ------------------------------------------------------
 113
 114    procedure Set_Input  (File : in File_Type);
 115    procedure Set_Output (File : in File_Type);
 116    procedure Set_Error  (File : in File_Type);
 117
 118    function Standard_Input  return File_Type;
 119    function Standard_Output return File_Type;
 120    function Standard_Error  return File_Type;
 121
 122    function Current_Input  return File_Type;
 123    function Current_Output return File_Type;
 124    function Current_Error  return File_Type;
 125
 126    type File_Access is access constant File_Type;
 127
 128    function Standard_Input  return File_Access;
 129    function Standard_Output return File_Access;
 130    function Standard_Error  return File_Access;
 131
 132    function Current_Input  return File_Access;
 133    function Current_Output return File_Access;
 134    function Current_Error  return File_Access;
 135
 136    --------------------
 137    -- Buffer control --
 138    --------------------
 139
 140    --  Note: The parameter file is IN OUT in the RM, but this is clearly
 141    --  an oversight, and was intended to be IN, see AI95-00057.
 142
 143    procedure Flush (File : in File_Type);
 144    procedure Flush;
 145
 146    --------------------------------------------
 147    -- Specification of line and page lengths --
 148    --------------------------------------------
 149
 150    procedure Set_Line_Length (File : in File_Type; To : in Count);
 151    procedure Set_Line_Length (To : in Count);
 152
 153    procedure Set_Page_Length (File : in File_Type; To : in Count);
 154    procedure Set_Page_Length (To : in Count);
 155
 156    function Line_Length (File : in File_Type) return Count;
 157    function Line_Length return Count;
 158
 159    function Page_Length (File : in File_Type) return Count;
 160    function Page_Length return Count;
 161
 162    ------------------------------------
 163    -- Column, Line, and Page Control --
 164    ------------------------------------
 165
 166    procedure New_Line (File : in File_Type; Spacing : in Positive_Count := 1);
 167    procedure New_Line (Spacing : in Positive_Count := 1);
 168
 169    procedure Skip_Line (File : in File_Type; Spacing : in Positive_Count := 1);
 170    procedure Skip_Line (Spacing : in Positive_Count := 1);
 171
 172    function End_Of_Line (File : in File_Type) return Boolean;
 173    function End_Of_Line return Boolean;
 174
 175    procedure New_Page (File : in File_Type);
 176    procedure New_Page;
 177
 178    procedure Skip_Page (File : in File_Type);
 179    procedure Skip_Page;
 180
 181    function End_Of_Page (File : in File_Type) return Boolean;
 182    function End_Of_Page return Boolean;
 183
 184    function End_Of_File (File : in File_Type) return Boolean;
 185    function End_Of_File return Boolean;
 186
 187    procedure Set_Col (File : in File_Type;  To : in Positive_Count);
 188    procedure Set_Col (To : in Positive_Count);
 189
 190    procedure Set_Line (File : in File_Type; To : in Positive_Count);
 191    procedure Set_Line (To : in Positive_Count);
 192
 193    function Col (File : in File_Type) return Positive_Count;
 194    function Col return Positive_Count;
 195
 196    function Line (File : in File_Type) return Positive_Count;
 197    function Line return Positive_Count;
 198
 199    function Page (File : in File_Type) return Positive_Count;
 200    function Page return Positive_Count;
 201
 202    ----------------------------
 203    -- Character Input-Output --
 204    ----------------------------
 205
 206    procedure Get (File : in File_Type; Item : out Character);
 207    procedure Get (Item : out Character);
 208    procedure Put (File : in File_Type; Item : in Character);
 209    procedure Put (Item : in Character);
 210
 211    procedure Look_Ahead
 212      (File        : in File_Type;
 213       Item        : out Character;
 214       End_Of_Line : out Boolean);
 215
 216    procedure Look_Ahead
 217      (Item        : out Character;
 218       End_Of_Line : out Boolean);
 219
 220    procedure Get_Immediate
 221      (File : in File_Type;
 222       Item : out Character);
 223
 224    procedure Get_Immediate
 225      (Item : out Character);
 226
 227    procedure Get_Immediate
 228      (File      : in File_Type;
 229       Item      : out Character;
 230       Available : out Boolean);
 231
 232    procedure Get_Immediate
 233      (Item      : out Character;
 234       Available : out Boolean);
 235
 236    -------------------------
 237    -- String Input-Output --
 238    -------------------------
 239
 240    procedure Get (File : in File_Type; Item : out String);
 241    procedure Get (Item : out String);
 242    procedure Put (File : in File_Type; Item : in String);
 243    procedure Put (Item : in String);
 244
 245    procedure Get_Line
 246      (File : in File_Type;
 247       Item : out String;
 248       Last : out Natural);
 249
 250    procedure Get_Line
 251      (Item : out String;
 252       Last : out Natural);
 253
 254    procedure Put_Line
 255      (File : in File_Type;
 256       Item : in String);
 257
 258    procedure Put_Line
 259      (Item : in String);
 260
 261    ---------------------------------------
 262    -- Generic packages for Input-Output --
 263    ---------------------------------------
 264
 265    --  The generic packages:
 266
 267    --    Ada.Text_IO.Integer_IO
 268    --    Ada.Text_IO.Modular_IO
 269    --    Ada.Text_IO.Float_IO
 270    --    Ada.Text_IO.Fixed_IO
 271    --    Ada.Text_IO.Decimal_IO
 272    --    Ada.Text_IO.Enumeration_IO
 273
 274    --  are implemented as separate child packages in GNAT, so the
 275    --  spec and body of these packages are to be found in separate
 276    --  child units. This implementation detail is hidden from the
 277    --  Ada programmer by special circuitry in the compiler that
 278    --  treats these child packages as though they were nested in
 279    --  Text_IO. The advantage of this special processing is that
 280    --  the subsidiary routines needed if these generics are used
 281    --  are not loaded when they are not used.
 282
 283    ----------------
 284    -- Exceptions --
 285    ----------------
 286
 287    Status_Error : exception renames IO_Exceptions.Status_Error;
 288    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 289    Name_Error   : exception renames IO_Exceptions.Name_Error;
 290    Use_Error    : exception renames IO_Exceptions.Use_Error;
 291    Device_Error : exception renames IO_Exceptions.Device_Error;
 292    End_Error    : exception renames IO_Exceptions.End_Error;
 293    Data_Error   : exception renames IO_Exceptions.Data_Error;
 294    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 295
 296 private
 297    -----------------------------------
 298    -- Handling of Format Characters --
 299    -----------------------------------
 300
 301    --  Line marks are represented by the single character ASCII.LF (16#0A#).
 302    --  In DOS and similar systems, underlying file translation takes care
 303    --  of translating this to and from the standard CR/LF sequences used in
 304    --  these operating systems to mark the end of a line. On output there is
 305    --  always a line mark at the end of the last line, but on input, this
 306    --  line mark can be omitted, and is implied by the end of file.
 307
 308    --  Page marks are represented by the single character ASCII.FF (16#0C#),
 309    --  The page mark at the end of the file may be omitted, and is normally
 310    --  omitted on output unless an explicit New_Page call is made before
 311    --  closing the file. No page mark is added when a file is appended to,
 312    --  so, in accordance with the permission in (RM A.10.2(4)), there may
 313    --  or may not be a page mark separating preexising text in the file
 314    --  from the new text to be written.
 315
 316    --  A file mark is marked by the physical end of file. In DOS translation
 317    --  mode on input, an EOF character (SUB = 16#1A#) gets translated to the
 318    --  physical end of file, so in effect this character is recognized as
 319    --  marking the end of file in DOS and similar systems.
 320
 321    LM : constant := Character'Pos (ASCII.LF);
 322    --  Used as line mark
 323
 324    PM : constant := Character'Pos (ASCII.FF);
 325    --  Used as page mark, except at end of file where it is implied
 326
 327    --------------------------------
 328    -- Text_IO File Control Block --
 329    --------------------------------
 330
 331    package FCB renames System.File_Control_Block;
 332
 333    type Text_AFCB;
 334    type File_Type is access all Text_AFCB;
 335
 336    type Text_AFCB is new FCB.AFCB with record
 337       Page        : Count := 1;
 338       Line        : Count := 1;
 339       Col         : Count := 1;
 340       Line_Length : Count := 0;
 341       Page_Length : Count := 0;
 342
 343       Self : aliased File_Type;
 344       --  Set to point to the containing Text_AFCB block. This is used to
 345       --  implement the Current_{Error,Input,Ouput} functions which return
 346       --  a File_Access, the file access value returned is a pointer to
 347       --  the Self field of the corresponding file.
 348
 349       Before_LM : Boolean := False;
 350       --  This flag is used to deal with the anomolies introduced by the
 351       --  peculiar definition of End_Of_File and End_Of_Page in Ada. These
 352       --  functions require looking ahead more than one character. Since
 353       --  there is no convenient way of backing up more than one character,
 354       --  what we do is to leave ourselves positioned past the LM, but set
 355       --  this flag, so that we know that from an Ada point of view we are
 356       --  in front of the LM, not after it. A bit of a kludge, but it works!
 357
 358       Before_LM_PM : Boolean := False;
 359       --  This flag similarly handles the case of being physically positioned
 360       --  after a LM-PM sequence when logically we are before the LM-PM. This
 361       --  flag can only be set if Before_LM is also set.
 362
 363    end record;
 364
 365    function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
 366
 367    procedure AFCB_Close (File : access Text_AFCB);
 368    procedure AFCB_Free  (File : access Text_AFCB);
 369
 370    procedure Read
 371      (File : in out Text_AFCB;
 372       Item : out Ada.Streams.Stream_Element_Array;
 373       Last : out Ada.Streams.Stream_Element_Offset);
 374    --  Read operation used when Text_IO file is treated directly as Stream
 375
 376    procedure Write
 377      (File : in out Text_AFCB;
 378       Item : in Ada.Streams.Stream_Element_Array);
 379    --  Write operation used when Text_IO file is treated directly as Stream
 380
 381    ------------------------
 382    -- The Standard Files --
 383    ------------------------
 384
 385    Null_Str : aliased constant String := "";
 386    --  Used as name and form of standard files
 387
 388    Standard_Err_AFCB : aliased Text_AFCB;
 389    Standard_In_AFCB  : aliased Text_AFCB;
 390    Standard_Out_AFCB : aliased Text_AFCB;
 391
 392    Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
 393    Standard_In  : aliased File_Type := Standard_In_AFCB'Access;
 394    Standard_Out : aliased File_Type := Standard_Out_AFCB'Access;
 395    --  Standard files
 396
 397    Current_In   : aliased File_Type := Standard_In;
 398    Current_Out  : aliased File_Type := Standard_Out;
 399    Current_Err  : aliased File_Type := Standard_Err;
 400    --  Current files
 401
 402    -----------------------
 403    -- Local Subprograms --
 404    -----------------------
 405
 406    --  These subprograms are in the private part of the spec so that they can
 407    --  be shared by the routines in the body of Ada.Text_IO.Wide_Text_IO.
 408
 409    --  Note: we use Integer in these declarations instead of the more accurate
 410    --  Interfaces.C_Streams.int, because we do not want to drag in the spec of
 411    --  this interfaces package with the spec of Ada.Text_IO, and we know that
 412    --  in fact these types are identical
 413
 414    function EOF_Char return Integer;
 415    --  Returns the system-specific character indicating the end of a text file.
 416    --  This is exported for use by child packages such as Enumeration_Aux to
 417    --  eliminate their needing to depend directly on Interfaces.C_Streams.
 418
 419    function Getc (File : File_Type) return Integer;
 420    --  Gets next character from file, which has already been checked for
 421    --  being in read status, and returns the character read if no error
 422    --  occurs. The result is EOF if the end of file was read.
 423
 424    function Nextc (File : File_Type) return Integer;
 425    --  Returns next character from file without skipping past it (i.e. it
 426    --  is a combination of Getc followed by an Ungetc).
 427
 428    procedure Putc (ch : Integer; File : File_Type);
 429    --  Outputs the given character to the file, which has already been
 430    --  checked for being in output status. Device_Error is raised if the
 431    --  character cannot be written.
 432
 433    procedure Terminate_Line (File : File_Type);
 434    --  If the file is in Write_File or Append_File mode, and the current
 435    --  line is not terminated, then a line terminator is written using
 436    --  New_Line. Note that there is no Terminate_Page routine, because
 437    --  the page mark at the end of the file is implied if necessary.
 438
 439    procedure Ungetc (ch : Integer; File : File_Type);
 440    --  Pushes back character into stream, using ungetc. The caller has
 441    --  checked that the file is in read status. Device_Error is raised
 442    --  if the character cannot be pushed back. An attempt to push back
 443    --  and end of file character (EOF) is ignored.
 444
 445 end Ada.Text_IO;