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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                     A D A . W I D E _ 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 Wide_Text_IO (Integer_IO, Float_IO,
  37 --  Fixed_IO, Modular_IO, Decimal_IO and Enumeration_IO) appear as private
  38 --  children in GNAT. These children are with'ed automatically if they are
  39 --  referenced, so this rearrangement is invisible to user programs, but has
  40 --  the advantage that only the needed parts of Wide_Text_IO are processed
  41 --  and loaded.
  42
  43 with Ada.IO_Exceptions;
  44 with Ada.Streams;
  45
  46 with Interfaces.C_Streams;
  47
  48 with System;
  49 with System.File_Control_Block;
  50 with System.WCh_Con;
  51
  52 package Ada.Wide_Text_IO is
  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 : File_Mode := Out_File;
  92       Name : String := "";
  93       Form : String := "");
  94
  95    procedure Open
  96      (File : in out File_Type;
  97       Mode : File_Mode;
  98       Name : String;
  99       Form : 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 : File_Mode);
 104    procedure Reset  (File : in out File_Type);
 105
 106    function Mode (File : File_Type) return File_Mode;
 107    function Name (File : File_Type) return String;
 108    function Form (File : File_Type) return String;
 109
 110    function Is_Open (File : File_Type) return Boolean;
 111
 112    ------------------------------------------------------
 113    -- Control of default input, output and error files --
 114    ------------------------------------------------------
 115
 116    procedure Set_Input  (File : File_Type);
 117    procedure Set_Output (File : File_Type);
 118    procedure Set_Error  (File : 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 as pointed out
 143    --  in <<95-5166.a Tucker Taft 95-6-23>> this is clearly an oversight.
 144
 145    procedure Flush (File : File_Type);
 146    procedure Flush;
 147
 148    --------------------------------------------
 149    -- Specification of line and page lengths --
 150    --------------------------------------------
 151
 152    procedure Set_Line_Length (File : File_Type; To : Count);
 153    procedure Set_Line_Length (To : Count);
 154
 155    procedure Set_Page_Length (File : File_Type; To : Count);
 156    procedure Set_Page_Length (To : Count);
 157
 158    function Line_Length (File : File_Type) return Count;
 159    function Line_Length return Count;
 160
 161    function Page_Length (File : 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 : File_Type; Spacing : Positive_Count := 1);
 169    procedure New_Line (Spacing : Positive_Count := 1);
 170
 171    procedure Skip_Line (File : File_Type; Spacing : Positive_Count := 1);
 172    procedure Skip_Line (Spacing : Positive_Count := 1);
 173
 174    function End_Of_Line (File : File_Type) return Boolean;
 175    function End_Of_Line return Boolean;
 176
 177    procedure New_Page (File : File_Type);
 178    procedure New_Page;
 179
 180    procedure Skip_Page (File : File_Type);
 181    procedure Skip_Page;
 182
 183    function End_Of_Page (File : File_Type) return Boolean;
 184    function End_Of_Page return Boolean;
 185
 186    function End_Of_File (File : File_Type) return Boolean;
 187    function End_Of_File return Boolean;
 188
 189    procedure Set_Col (File : File_Type;  To : Positive_Count);
 190    procedure Set_Col (To : Positive_Count);
 191
 192    procedure Set_Line (File : File_Type; To : Positive_Count);
 193    procedure Set_Line (To : Positive_Count);
 194
 195    function Col (File : File_Type) return Positive_Count;
 196    function Col return Positive_Count;
 197
 198    function Line (File : File_Type) return Positive_Count;
 199    function Line return Positive_Count;
 200
 201    function Page (File : File_Type) return Positive_Count;
 202    function Page return Positive_Count;
 203
 204    ----------------------------
 205    -- Character Input-Output --
 206    ----------------------------
 207
 208    procedure Get (File : File_Type; Item : out Wide_Character);
 209    procedure Get (Item : out Wide_Character);
 210    procedure Put (File : File_Type; Item : Wide_Character);
 211    procedure Put (Item : Wide_Character);
 212
 213    procedure Look_Ahead
 214      (File        : File_Type;
 215       Item        : out Wide_Character;
 216       End_Of_Line : out Boolean);
 217
 218    procedure Look_Ahead
 219      (Item        : out Wide_Character;
 220       End_Of_Line : out Boolean);
 221
 222    procedure Get_Immediate
 223      (File : File_Type;
 224       Item : out Wide_Character);
 225
 226    procedure Get_Immediate
 227      (Item : out Wide_Character);
 228
 229    procedure Get_Immediate
 230      (File      : File_Type;
 231       Item      : out Wide_Character;
 232       Available : out Boolean);
 233
 234    procedure Get_Immediate
 235      (Item      : out Wide_Character;
 236       Available : out Boolean);
 237
 238    -------------------------
 239    -- String Input-Output --
 240    -------------------------
 241
 242    procedure Get (File : File_Type; Item : out Wide_String);
 243    procedure Get (Item : out Wide_String);
 244    procedure Put (File : File_Type; Item : Wide_String);
 245    procedure Put (Item : Wide_String);
 246
 247    procedure Get_Line
 248      (File : File_Type;
 249       Item : out Wide_String;
 250       Last : out Natural);
 251
 252    procedure Get_Line
 253      (Item : out Wide_String;
 254       Last : out Natural);
 255
 256    function Get_Line (File : File_Type) return Wide_String;
 257    pragma Ada_05 (Get_Line);
 258
 259    function Get_Line return Wide_String;
 260    pragma Ada_05 (Get_Line);
 261
 262    procedure Put_Line
 263      (File : File_Type;
 264       Item : Wide_String);
 265
 266    procedure Put_Line
 267      (Item : Wide_String);
 268
 269    ---------------------------------------
 270    -- Generic packages for Input-Output --
 271    ---------------------------------------
 272
 273    --  The generic packages:
 274
 275    --    Ada.Wide_Text_IO.Integer_IO
 276    --    Ada.Wide_Text_IO.Modular_IO
 277    --    Ada.Wide_Text_IO.Float_IO
 278    --    Ada.Wide_Text_IO.Fixed_IO
 279    --    Ada.Wide_Text_IO.Decimal_IO
 280    --    Ada.Wide_Text_IO.Enumeration_IO
 281
 282    --  are implemented as separate child packages in GNAT, so the
 283    --  spec and body of these packages are to be found in separate
 284    --  child units. This implementation detail is hidden from the
 285    --  Ada programmer by special circuitry in the compiler that
 286    --  treats these child packages as though they were nested in
 287    --  Text_IO. The advantage of this special processing is that
 288    --  the subsidiary routines needed if these generics are used
 289    --  are not loaded when they are not used.
 290
 291    ----------------
 292    -- Exceptions --
 293    ----------------
 294
 295    Status_Error : exception renames IO_Exceptions.Status_Error;
 296    Mode_Error   : exception renames IO_Exceptions.Mode_Error;
 297    Name_Error   : exception renames IO_Exceptions.Name_Error;
 298    Use_Error    : exception renames IO_Exceptions.Use_Error;
 299    Device_Error : exception renames IO_Exceptions.Device_Error;
 300    End_Error    : exception renames IO_Exceptions.End_Error;
 301    Data_Error   : exception renames IO_Exceptions.Data_Error;
 302    Layout_Error : exception renames IO_Exceptions.Layout_Error;
 303
 304 private
 305
 306    --  The following procedures have a File_Type formal of mode IN OUT because
 307    --  they may close the original file. The Close operation may raise an
 308    --  exception, but in that case we want any assignment to the formal to
 309    --  be effective anyway, so it must be passed by reference (or the caller
 310    --  will be left with a dangling pointer).
 311
 312    pragma Export_Procedure
 313      (Internal  => Close,
 314       External  => "",
 315       Mechanism => Reference);
 316    pragma Export_Procedure
 317      (Internal  => Delete,
 318       External  => "",
 319       Mechanism => Reference);
 320    pragma Export_Procedure
 321      (Internal        => Reset,
 322       External        => "",
 323       Parameter_Types => (File_Type),
 324       Mechanism       => Reference);
 325    pragma Export_Procedure
 326      (Internal        => Reset,
 327       External        => "",
 328       Parameter_Types => (File_Type, File_Mode),
 329       Mechanism       => (File => Reference));
 330
 331    package WCh_Con renames System.WCh_Con;
 332
 333    -----------------------------------
 334    -- Handling of Format Characters --
 335    -----------------------------------
 336
 337    --  Line marks are represented by the single character ASCII.LF (16#0A#).
 338    --  In DOS and similar systems, underlying file translation takes care
 339    --  of translating this to and from the standard CR/LF sequences used in
 340    --  these operating systems to mark the end of a line. On output there is
 341    --  always a line mark at the end of the last line, but on input, this
 342    --  line mark can be omitted, and is implied by the end of file.
 343
 344    --  Page marks are represented by the single character ASCII.FF (16#0C#),
 345    --  The page mark at the end of the file may be omitted, and is normally
 346    --  omitted on output unless an explicit New_Page call is made before
 347    --  closing the file. No page mark is added when a file is appended to,
 348    --  so, in accordance with the permission in (RM A.10.2(4)), there may
 349    --  or may not be a page mark separating preexisting text in the file
 350    --  from the new text to be written.
 351
 352    --  A file mark is marked by the physical end of file. In DOS translation
 353    --  mode on input, an EOF character (SUB = 16#1A#) gets translated to the
 354    --  physical end of file, so in effect this character is recognized as
 355    --  marking the end of file in DOS and similar systems.
 356
 357    LM : constant := Character'Pos (ASCII.LF);
 358    --  Used as line mark
 359
 360    PM : constant := Character'Pos (ASCII.FF);
 361    --  Used as page mark, except at end of file where it is implied
 362
 363    -------------------------------------
 364    -- Wide_Text_IO File Control Block --
 365    -------------------------------------
 366
 367    Default_WCEM : WCh_Con.WC_Encoding_Method := WCh_Con.WCEM_UTF8;
 368    --  This gets modified during initialization (see body) using
 369    --  the default value established in the call to Set_Globals.
 370
 371    package FCB renames System.File_Control_Block;
 372
 373    type Wide_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 : WCh_Con.WC_Encoding_Method := Default_WCEM;
 401       --  Encoding method to be used for this file
 402
 403       Before_Wide_Character : Boolean := False;
 404       --  This flag is set to indicate that a wide character in the input has
 405       --  been read by Wide_Text_IO.Look_Ahead. If it is set to True, then it
 406       --  means that the stream is logically positioned before the character
 407       --  but is physically positioned after it. The character involved must
 408       --  not be in the range 16#00#-16#7F#, i.e. if the flag is set, then
 409       --  we know the next character has a code greater than 16#7F#, and the
 410       --  value of this character is saved in Saved_Wide_Character.
 411
 412       Saved_Wide_Character : Wide_Character;
 413       --  This field is valid only if Before_Wide_Character is set. It
 414       --  contains a wide character read by Look_Ahead. If Look_Ahead
 415       --  reads a character in the range 16#0000# to 16#007F#, then it
 416       --  can use ungetc to put it back, but ungetc cannot be called
 417       --  more than once, so for characters above this range, we don't
 418       --  try to back up the file. Instead we save the character in this
 419       --  field and set the flag Before_Wide_Character to indicate that
 420       --  we are logically positioned before this character even though
 421       --  the stream is physically positioned after it.
 422
 423    end record;
 424
 425    type File_Type is access all Wide_Text_AFCB;
 426
 427    function AFCB_Allocate (Control_Block : Wide_Text_AFCB) return FCB.AFCB_Ptr;
 428
 429    procedure AFCB_Close (File : not null access Wide_Text_AFCB);
 430    procedure AFCB_Free  (File : not null access Wide_Text_AFCB);
 431
 432    procedure Read
 433      (File : in out Wide_Text_AFCB;
 434       Item : out Ada.Streams.Stream_Element_Array;
 435       Last : out Ada.Streams.Stream_Element_Offset);
 436    --  Read operation used when Wide_Text_IO file is treated as a Stream
 437
 438    procedure Write
 439      (File : in out Wide_Text_AFCB;
 440       Item : Ada.Streams.Stream_Element_Array);
 441    --  Write operation used when Wide_Text_IO file is treated as a Stream
 442
 443    ------------------------
 444    -- The Standard Files --
 445    ------------------------
 446
 447    Standard_Err_AFCB : aliased Wide_Text_AFCB;
 448    Standard_In_AFCB  : aliased Wide_Text_AFCB;
 449    Standard_Out_AFCB : aliased Wide_Text_AFCB;
 450
 451    Standard_Err : aliased File_Type := Standard_Err_AFCB'Access;
 452    Standard_In  : aliased File_Type := Standard_In_AFCB'Access;
 453    Standard_Out : aliased File_Type := Standard_Out_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    procedure Initialize_Standard_Files;
 462    --  Initializes the file control blocks for the standard files. Called from
 463    --  the elaboration routine for this package, and from Reset_Standard_Files
 464    --  in package Ada.Wide_Text_IO.Reset_Standard_Files.
 465
 466    -----------------------
 467    -- Local Subprograms --
 468    -----------------------
 469
 470    --  These subprograms are in the private part of the spec so that they can
 471    --  be shared by the children of Ada.Wide_Text_IO.
 472
 473    function Getc (File : File_Type) return Interfaces.C_Streams.int;
 474    --  Gets next character from file, which has already been checked for being
 475    --  in read status, and returns the character read if no error occurs. The
 476    --  result is EOF if the end of file was read.
 477
 478    procedure Get_Character (File : File_Type; Item : out Character);
 479    --  This is essentially a copy of the normal Get routine from Text_IO. It
 480    --  obtains a single character from the input file File, and places it in
 481    --  Item. This character may be the leading character of a Wide_Character
 482    --  sequence, but that is up to the caller to deal with.
 483
 484    function Get_Wide_Char
 485      (C    : Character;
 486       File : File_Type) return Wide_Character;
 487    --  This function is shared by Get and Get_Immediate to extract a wide
 488    --  character value from the given File. The first byte has already been
 489    --  read and is passed in C. The wide character value is returned as the
 490    --  result, and the file pointer is bumped past the character.
 491
 492    function Nextc (File : File_Type) return Interfaces.C_Streams.int;
 493    --  Returns next character from file without skipping past it (i.e. it is a
 494    --  combination of Getc followed by an Ungetc).
 495
 496 end Ada.Wide_Text_IO;