gcc/ada/s-fileio.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                       S Y S T E M . F I L E _ I O                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2004, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides support for the routines described in (RM A.8.2)
  35 --  which are common to Text_IO, Direct_IO, Sequential_IO and Stream_IO.
  36
  37 with Interfaces.C_Streams;
  38
  39 with System.File_Control_Block;
  40
  41 package System.File_IO is
  42
  43    package FCB renames System.File_Control_Block;
  44    package ICS renames Interfaces.C_Streams;
  45
  46    ---------------------
  47    -- File Management --
  48    ---------------------
  49
  50    procedure Open
  51      (File_Ptr  : in out FCB.AFCB_Ptr;
  52       Dummy_FCB : in FCB.AFCB'Class;
  53       Mode      : FCB.File_Mode;
  54       Name      : String;
  55       Form      : String;
  56       Amethod   : Character;
  57       Creat     : Boolean;
  58       Text      : Boolean;
  59       C_Stream  : ICS.FILEs := ICS.NULL_Stream);
  60    --  This routine is used for both Open and Create calls:
  61    --
  62    --    File_Ptr is the file type, which must be null on entry
  63    --    (i.e. the file must be closed before the call).
  64    --
  65    --    Dummy_FCB is a default initialized file control block of appropriate
  66    --    type. Note that the tag of this record indicates the type and length
  67    --    of the control block. This control block is used only for the purpose
  68    --    of providing the controlling argument for calling the write version
  69    --    of Allocate_AFCB. It has no other purpose, and its fields are never
  70    --    read or written.
  71    --
  72    --    Mode is the required mode
  73    --
  74    --    Name is the file name, with a null string indicating that a temporary
  75    --    file is to be created (only permitted in create mode, not open mode)
  76    --
  77    --    Creat is True for a create call, and false for an open call
  78    --
  79    --    Text is set True to open the file in text mode (w+t or r+t) instead
  80    --    of the usual binary mode open (w+b or r+b).
  81    --
  82    --    Form is the form string given in the open or create call, this is
  83    --    stored in the AFCB, but otherwise is not used by this or any other
  84    --    routine in this unit (except Form which retrieves the original value)
  85    --
  86    --    Amethod indicates the access method
  87    --
  88    --      D = Direct_IO
  89    --      Q = Sequential_IO
  90    --      S = Stream_IO
  91    --      T = Text_IO
  92    --      W = Wide_Text_IO
  93    --
  94    --    C_Stream is left at its default value for the normal case of an
  95    --    Open or Create call as defined in the RM. The only time this is
  96    --    non-null is for the Open call from Ada.xxx_IO.C_Streams.Open.
  97    --
  98    --  On return, if the open/create succeeds, then the fields of File are
  99    --  filled in, and this value is copied to the heap. File_Ptr points to
 100    --  this allocated file control block. If the open/create fails, then the
 101    --  fields of File are undefined, and File_Ptr is unchanged.
 102
 103    procedure Close (File : in out FCB.AFCB_Ptr);
 104    --  The file is closed, all storage associated with it is released, and
 105    --  File is set to null. Note that this routine calls AFCB_Close to perform
 106    --  any specialized close actions, then closes the file at the system level,
 107    --  then frees the mode and form strings, and finally calls AFCB_Free to
 108    --  free the file control block itself, setting File to null.
 109
 110    procedure Delete (File : in out FCB.AFCB_Ptr);
 111    --  The indicated file is unlinked
 112
 113    procedure Reset (File : in out FCB.AFCB_Ptr; Mode : in FCB.File_Mode);
 114    --  The file is reset, and the mode changed as indicated.
 115
 116    procedure Reset (File : in out FCB.AFCB_Ptr);
 117    --  The files is reset, and the mode is unchanged
 118
 119    function Mode (File : in FCB.AFCB_Ptr) return FCB.File_Mode;
 120    --  Returns the mode as supplied by create, open or reset
 121
 122    function Name (File : in FCB.AFCB_Ptr) return String;
 123    --  Returns the file name as supplied by Open or Create. Raises Use_Error
 124    --  if used with temporary files or standard files.
 125
 126    function Form (File : in FCB.AFCB_Ptr) return String;
 127    --  Returns the form as supplied by create, open or reset
 128    --  The string is normalized to all lower case letters.
 129
 130    function Is_Open (File : in FCB.AFCB_Ptr) return Boolean;
 131    --  Determines if file is open or not
 132
 133    ----------------------
 134    -- Utility Routines --
 135    ----------------------
 136
 137    --  Some internal routines not defined in A.8.2. These are routines which
 138    --  provide required common functionality shared by separate packages.
 139
 140    procedure Chain_File (File : FCB.AFCB_Ptr);
 141    --  Used to chain the given file into the list of open files. Normally this
 142    --  is done implicitly by Open. Chain_File is used for the spcial cases of
 143    --  the system files defined by Text_IO (stdin, stdout, stderr) which are
 144    --  not opened in the normal manner. Note that the caller is responsible
 145    --  for task lock out to protect the global data structures if this is
 146    --  necessary (it is needed for the calls from within this unit itself,
 147    --  but not required for the calls from Text_IO and Wide_Text_IO that
 148    --  are made during elaboration of the environment task).
 149
 150    procedure Check_File_Open (File : FCB.AFCB_Ptr);
 151    --  If the current file is not open, then Status_Error is raised.
 152    --  Otherwise control returns normally (with File pointing to the
 153    --  control block for the open file.
 154
 155    procedure Check_Read_Status (File : FCB.AFCB_Ptr);
 156    --  If the current file is not open, then Status_Error is raised. If
 157    --  the file is open, then the mode is checked to ensure that reading
 158    --  is permitted, and if not Mode_Error is raised, otherwise control
 159    --  returns normally.
 160
 161    procedure Check_Write_Status (File : FCB.AFCB_Ptr);
 162    --  If the current file is not open, then Status_Error is raised. If
 163    --  the file is open, then the mode is checked to ensure that writing
 164    --  is permitted, and if not Mode_Error is raised, otherwise control
 165    --  returns normally.
 166
 167    function End_Of_File (File : FCB.AFCB_Ptr) return Boolean;
 168    --  File must be opened in read mode. True is returned if the stream is
 169    --  currently positioned at the end of file, otherwise False is returned.
 170    --  The position of the stream is not affected.
 171
 172    procedure Flush (File : FCB.AFCB_Ptr);
 173    --  Flushes the stream associated with the given file. The file must be
 174    --  open and in write mode (if not, an appropriate exception is raised)
 175
 176    function Form_Boolean
 177      (Form    : String;
 178       Keyword : String;
 179       Default : Boolean)
 180       return    Boolean;
 181    --  Searches form string for an entry of the form Keyword=xx where xx is
 182    --  either Yes/No or y/n. Returns True if Yes or Y is found, False if No
 183    --  or N is found. If the keyword parameter is not found, returns the
 184    --  value given as Default. May raise Use_Error if a form string syntax
 185    --  error is detected. Keyword and Form must be in lower case.
 186
 187    function Form_Integer
 188      (Form    : String;
 189       Keyword : String;
 190       Default : Integer)
 191       return    Integer;
 192    --  Searches form string for an entry of the form Keyword=xx where xx is
 193    --  an unsigned decimal integer in the range 0 to 999_999. Returns this
 194    --  integer value if it is found. If the keyword parameter is not found,
 195    --  returns the value given as Default. Raise Use_Error if a form string
 196    --  syntax error is detected. Keyword and Form must be in lower case.
 197
 198    procedure Form_Parameter
 199      (Form    : String;
 200       Keyword : String;
 201       Start   : out Natural;
 202       Stop    : out Natural);
 203    --  Searches form string for an entry of the form Keyword=xx and if found
 204    --  Sets Start and Stop to the first and last characters of xx. Keyword
 205    --  and Form must be in lower case. If no entry matches, then Start and
 206    --  Stop are set to zero on return. Use_Error is raised if a malformed
 207    --  string is detected, but there is no guarantee of full syntax checking.
 208
 209    procedure Read_Buf
 210      (File : FCB.AFCB_Ptr;
 211       Buf  : Address;
 212       Siz  : Interfaces.C_Streams.size_t);
 213    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 214    --  that the file is open in read mode. Raises an exception if Siz bytes
 215    --  cannot be read (End_Error if no data was read, Data_Error if a partial
 216    --  buffer was read, Device_Error if an error occurs).
 217
 218    procedure Read_Buf
 219      (File  : FCB.AFCB_Ptr;
 220       Buf   : Address;
 221       Siz   : in Interfaces.C_Streams.size_t;
 222       Count : out Interfaces.C_Streams.size_t);
 223    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 224    --  that the file is open in read mode. Device Error is raised if an error
 225    --  occurs. Count is the actual number of bytes read, which may be less
 226    --  than Siz if the end of file is encountered.
 227
 228    procedure Append_Set (File : FCB.AFCB_Ptr);
 229    --  If the mode of the file is Append_File, then the file is positioned
 230    --  at the end of file using fseek, otherwise this call has no effect.
 231
 232    procedure Write_Buf
 233      (File : FCB.AFCB_Ptr;
 234       Buf  : Address;
 235       Siz  : Interfaces.C_Streams.size_t);
 236    --  Writes size_t bytes to File.Stream from Buf. The caller has checked
 237    --  that the file is open in write mode. Raises Device_Error if the
 238    --  complete buffer cannot be written.
 239
 240    procedure Make_Unbuffered (File : FCB.AFCB_Ptr);
 241
 242    procedure Make_Line_Buffered
 243      (File     : FCB.AFCB_Ptr;
 244       Line_Siz : Interfaces.C_Streams.size_t);
 245
 246    procedure Make_Buffered
 247      (File     : FCB.AFCB_Ptr;
 248       Buf_Siz  : Interfaces.C_Streams.size_t);
 249
 250 private
 251    pragma Inline (Check_Read_Status);
 252    pragma Inline (Check_Write_Status);
 253    pragma Inline (Mode);
 254
 255 end System.File_IO;