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) 1992-2009, 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
  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
  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 : File_Mode := Out_File;
  90       Name : String := "";
  91       Form : String := "");
  92
  93    procedure Open
  94      (File : in out File_Type;
  95       Mode : File_Mode;
  96       Name : String;
  97       Form : 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 : File_Mode);
 102    procedure Reset  (File : in out File_Type);
 103
 104    function Mode (File : File_Type) return File_Mode;
 105    function Name (File : File_Type) return String;
 106    function Form (File : File_Type) return String;
 107
 108    function Is_Open (File : File_Type) return Boolean;
 109
 110    ------------------------------------------------------
 111    -- Control of default input, output and error files --
 112    ------------------------------------------------------
 113
 114    procedure Set_Input  (File : File_Type);
 115    procedure Set_Output (File : File_Type);
 116    procedure Set_Error  (File : 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 : File_Type);
 144    procedure Flush;
 145
 146    --------------------------------------------
 147    -- Specification of line and page lengths --
 148    --------------------------------------------
 149
 150    procedure Set_Line_Length (File : File_Type; To : Count);
 151    procedure Set_Line_Length (To : Count);
 152
 153    procedure Set_Page_Length (File : File_Type; To : Count);
 154    procedure Set_Page_Length (To : Count);
 155
 156    function Line_Length (File : File_Type) return Count;
 157    function Line_Length return Count;
 158
 159    function Page_Length (File : 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 : File_Type; Spacing : Positive_Count := 1);
 167    procedure New_Line (Spacing : Positive_Count := 1);
 168
 169    procedure Skip_Line (File : File_Type; Spacing : Positive_Count := 1);
 170    procedure Skip_Line (Spacing : Positive_Count := 1);
 171
 172    function End_Of_Line (File : File_Type) return Boolean;
 173    function End_Of_Line return Boolean;
 174
 175    procedure New_Page (File : File_Type);
 176    procedure New_Page;
 177
 178    procedure Skip_Page (File : File_Type);
 179    procedure Skip_Page;
 180
 181    function End_Of_Page (File : File_Type) return Boolean;
 182    function End_Of_Page return Boolean;
 183
 184    function End_Of_File (File : File_Type) return Boolean;
 185    function End_Of_File return Boolean;
 186
 187    procedure Set_Col (File : File_Type;  To : Positive_Count);
 188    procedure Set_Col (To : Positive_Count);
 189
 190    procedure Set_Line (File : File_Type; To : Positive_Count);
 191    procedure Set_Line (To : Positive_Count);
 192
 193    function Col (File : File_Type) return Positive_Count;
 194    function Col return Positive_Count;
 195
 196    function Line (File : File_Type) return Positive_Count;
 197    function Line return Positive_Count;
 198
 199    function Page (File : File_Type) return Positive_Count;
 200    function Page return Positive_Count;
 201
 202    ----------------------------
 203    -- Character Input-Output --
 204    ----------------------------
 205
 206    procedure Get (File : File_Type; Item : out Character);
 207    procedure Get (Item : out Character);
 208    procedure Put (File : File_Type; Item : Character);
 209    procedure Put (Item : Character);
 210
 211    procedure Look_Ahead
 212      (File        : 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 : File_Type;
 222       Item : out Character);
 223
 224    procedure Get_Immediate
 225      (Item : out Character);
 226
 227    procedure Get_Immediate
 228      (File      : 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 : File_Type; Item : out String);
 241    procedure Get (Item : out String);
 242    procedure Put (File : File_Type; Item : String);
 243    procedure Put (Item : String);
 244
 245    procedure Get_Line
 246      (File : 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    function Get_Line (File : File_Type) return String;
 255    pragma Ada_05 (Get_Line);
 256
 257    function Get_Line return String;
 258    pragma Ada_05 (Get_Line);
 259
 260    procedure Put_Line
 261      (File : File_Type;
 262       Item : String);
 263
 264    procedure Put_Line
 265      (Item : String);
 266
 267    ---------------------------------------
 268    -- Generic packages for Input-Output --
 269    ---------------------------------------
 270
 271    --  The generic packages:
 272
 273    --    Ada.Text_IO.Integer_IO
 274    --    Ada.Text_IO.Modular_IO
 275    --    Ada.Text_IO.Float_IO
 276    --    Ada.Text_IO.Fixed_IO
 277    --    Ada.Text_IO.Decimal_IO
 278    --    Ada.Text_IO.Enumeration_IO
 279
 280    --  are implemented as separate child packages in GNAT, so the
 281    --  spec and body of these packages are to be found in separate
 282    --  child units. This implementation detail is hidden from the
 283    --  Ada programmer by special circuitry in the compiler that
 284    --  treats these child packages as though they were nested in
 285    --  Text_IO. The advantage of this special processing is that
 286    --  the subsidiary routines needed if these generics are used
 287    --  are not loaded when they are not used.
 288
 289    ----------------
 290    -- Exceptions --
 291    ----------------
 292
 293    Status_Error : exception renames IO_Exceptions.Status_Error;
 294    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 295    Name_Error   : exception renames IO_Exceptions.Name_Error;
 296    Use_Error    : exception renames IO_Exceptions.Use_Error;
 297    Device_Error : exception renames IO_Exceptions.Device_Error;
 298    End_Error    : exception renames IO_Exceptions.End_Error;
 299    Data_Error   : exception renames IO_Exceptions.Data_Error;
 300    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 301
 302 private
 303
 304    --  The following procedures have a File_Type formal of mode IN OUT because
 305    --  they may close the original file. The Close operation may raise an
 306    --  exception, but in that case we want any assignment to the formal to
 307    --  be effective anyway, so it must be passed by reference (or the caller
 308    --  will be left with a dangling pointer).
 309
 310    pragma Export_Procedure
 311      (Internal  => Close,
 312       External  => "",
 313       Mechanism => Reference);
 314    pragma Export_Procedure
 315      (Internal  => Delete,
 316       External  => "",
 317       Mechanism => Reference);
 318    pragma Export_Procedure
 319      (Internal        => Reset,
 320       External        => "",
 321       Parameter_Types => (File_Type),
 322       Mechanism       => Reference);
 323    pragma Export_Procedure
 324      (Internal        => Reset,
 325       External        => "",
 326       Parameter_Types => (File_Type, File_Mode),
 327       Mechanism       => (File => Reference));
 328
 329    -----------------------------------
 330    -- Handling of Format Characters --
 331    -----------------------------------
 332
 333    --  Line marks are represented by the single character ASCII.LF (16#0A#).
 334    --  In DOS and similar systems, underlying file translation takes care
 335    --  of translating this to and from the standard CR/LF sequences used in
 336    --  these operating systems to mark the end of a line. On output there is
 337    --  always a line mark at the end of the last line, but on input, this
 338    --  line mark can be omitted, and is implied by the end of file.
 339
 340    --  Page marks are represented by the single character ASCII.FF (16#0C#),
 341    --  The page mark at the end of the file may be omitted, and is normally
 342    --  omitted on output unless an explicit New_Page call is made before
 343    --  closing the file. No page mark is added when a file is appended to,
 344    --  so, in accordance with the permission in (RM A.10.2(4)), there may
 345    --  or may not be a page mark separating preexisting text in the file
 346    --  from the new text to be written.
 347
 348    --  A file mark is marked by the physical end of file. In DOS translation
 349    --  mode on input, an EOF character (SUB = 16#1A#) gets translated to the
 350    --  physical end of file, so in effect this character is recognized as
 351    --  marking the end of file in DOS and similar systems.
 352
 353    LM : constant := Character'Pos (ASCII.LF);
 354    --  Used as line mark
 355
 356    PM : constant := Character'Pos (ASCII.FF);
 357    --  Used as page mark, except at end of file where it is implied
 358
 359    --------------------------------
 360    -- Text_IO File Control Block --
 361    --------------------------------
 362
 363    Default_WCEM : System.WCh_Con.WC_Encoding_Method :=
 364                     System.WCh_Con.WCEM_UTF8;
 365    --  This gets modified during initialization (see body) using
 366    --  the default value established in the call to Set_Globals.
 367
 368    package FCB renames System.File_Control_Block;
 369
 370    type Text_AFCB;
 371    type File_Type is access all Text_AFCB;
 372
 373    type Text_AFCB is new FCB.AFCB with record
 374       Page        : Count := 1;
 375       Line        : Count := 1;
 376       Col         : Count := 1;
 377       Line_Length : Count := 0;
 378       Page_Length : Count := 0;
 379
 380       Self : aliased File_Type;
 381       --  Set to point to the containing Text_AFCB block. This is used to
 382       --  implement the Current_{Error,Input,Output} functions which return
 383       --  a File_Access, the file access value returned is a pointer to
 384       --  the Self field of the corresponding file.
 385
 386       Before_LM : Boolean := False;
 387       --  This flag is used to deal with the anomalies introduced by the
 388       --  peculiar definition of End_Of_File and End_Of_Page in Ada. These
 389       --  functions require looking ahead more than one character. Since
 390       --  there is no convenient way of backing up more than one character,
 391       --  what we do is to leave ourselves positioned past the LM, but set
 392       --  this flag, so that we know that from an Ada point of view we are
 393       --  in front of the LM, not after it. A bit of a kludge, but it works!
 394
 395       Before_LM_PM : Boolean := False;
 396       --  This flag similarly handles the case of being physically positioned
 397       --  after a LM-PM sequence when logically we are before the LM-PM. This
 398       --  flag can only be set if Before_LM is also set.
 399
 400       WC_Method : System.WCh_Con.WC_Encoding_Method := Default_WCEM;
 401       --  Encoding method to be used for this file. Text_IO does not deal with
 402       --  wide characters, but it does deal with upper half characters in the
 403       --  range 16#80#-16#FF# which may need encoding, e.g. in UTF-8 mode.
 404
 405       Before_Upper_Half_Character : Boolean := False;
 406       --  This flag is set to indicate that an encoded upper half character has
 407       --  been read by Text_IO.Look_Ahead. If it is set to True, then it means
 408       --  that the stream is logically positioned before the character but is
 409       --  physically positioned after it. The character involved must be in
 410       --  the range 16#80#-16#FF#, i.e. if the flag is set, then we know the
 411       --  next character has a code greater than 16#7F#, and the value of this
 412       --  character is saved in Saved_Upper_Half_Character.
 413
 414       Saved_Upper_Half_Character : Character;
 415       --  This field is valid only if Before_Upper_Half_Character is set. It
 416       --  contains an upper-half character read by Look_Ahead. If Look_Ahead
 417       --  reads a character in the range 16#00# to 16#7F#, then it can use
 418       --  ungetc to put it back, but ungetc cannot be called more than once,
 419       --  so for characters above this range, we don't try to back up the
 420       --  file. Instead we save the character in this field and set the flag
 421       --  Before_Upper_Half_Character to True to indicate that we are logically
 422       --  positioned before this character even though the stream is physically
 423       --  positioned after it.
 424
 425    end record;
 426
 427    function AFCB_Allocate (Control_Block : Text_AFCB) return FCB.AFCB_Ptr;
 428
 429    procedure AFCB_Close (File : not null access Text_AFCB);
 430    procedure AFCB_Free  (File : not null access Text_AFCB);
 431
 432    procedure Read
 433      (File : in out Text_AFCB;
 434       Item : out Ada.Streams.Stream_Element_Array;
 435       Last : out Ada.Streams.Stream_Element_Offset);
 436    --  Read operation used when Text_IO file is treated directly as Stream
 437
 438    procedure Write
 439      (File : in out Text_AFCB;
 440       Item : Ada.Streams.Stream_Element_Array);
 441    --  Write operation used when Text_IO file is treated directly as Stream
 442
 443    ------------------------
 444    -- The Standard Files --
 445    ------------------------
 446
 447    Standard_In_AFCB  : aliased Text_AFCB;
 448    Standard_Out_AFCB : aliased Text_AFCB;
 449    Standard_Err_AFCB : aliased Text_AFCB;
 450
 451    Standard_In  : aliased File_Type := Standard_In_AFCB'Access;
 452    Standard_Out : aliased File_Type := Standard_Out_AFCB'Access;
 453    Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
 454    --  Standard files
 455
 456    Current_In   : aliased File_Type := Standard_In;
 457    Current_Out  : aliased File_Type := Standard_Out;
 458    Current_Err  : aliased File_Type := Standard_Err;
 459    --  Current files
 460
 461    function EOF_Char return Integer;
 462    --  Returns the system-specific character indicating the end of a text file.
 463    --  This is exported for use by child packages such as Enumeration_Aux to
 464    --  eliminate their needing to depend directly on Interfaces.C_Streams,
 465    --  which is not available in certain target environments (such as AAMP).
 466
 467    procedure Initialize_Standard_Files;
 468    --  Initializes the file control blocks for the standard files. Called from
 469    --  the elaboration routine for this package, and from Reset_Standard_Files
 470    --  in package Ada.Text_IO.Reset_Standard_Files.
 471
 472 end Ada.Text_IO;