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 --                                                                          --
  10 --          Copyright (C) 1992-2001, Free Software Foundation, Inc.         --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This package provides support for the routines described in (RM A.8.2)
  36 --  which are common to Text_IO, Direct_IO, Sequential_IO and Stream_IO.
  37
  38 with Interfaces.C_Streams;
  39
  40 with System.File_Control_Block;
  41
  42 package System.File_IO is
  43
  44    package FCB renames System.File_Control_Block;
  45    package ICS renames Interfaces.C_Streams;
  46
  47    ---------------------
  48    -- File Management --
  49    ---------------------
  50
  51    procedure Open
  52      (File_Ptr  : in out FCB.AFCB_Ptr;
  53       Dummy_FCB : in out FCB.AFCB'Class;
  54       Mode      : FCB.File_Mode;
  55       Name      : String;
  56       Form      : String;
  57       Amethod   : Character;
  58       Creat     : Boolean;
  59       Text      : Boolean;
  60       C_Stream  : ICS.FILEs := ICS.NULL_Stream);
  61    --  This routine is used for both Open and Create calls:
  62    --
  63    --    File_Ptr is the file type, which must be null on entry
  64    --    (i.e. the file must be closed before the call).
  65    --
  66    --    Dummy_FCB is a default initialized file control block of appropriate
  67    --    type. Note that the tag of this record indicates the type and length
  68    --    of the control block. This control block is used only for the purpose
  69    --    of providing the controlling argument for calling the write version
  70    --    of Allocate_AFCB. It has no other purpose, and its fields are never
  71    --    read or written.
  72    --
  73    --    Mode is the required mode
  74    --
  75    --    Name is the file name, with a null string indicating that a temporary
  76    --    file is to be created (only permitted in create mode, not open mode)
  77    --
  78    --    Creat is True for a create call, and false for an open call
  79    --
  80    --    Text is set True to open the file in text mode (w+t or r+t) instead
  81    --    of the usual binary mode open (w+b or r+b).
  82    --
  83    --    Form is the form string given in the open or create call, this is
  84    --    stored in the AFCB, but otherwise is not used by this or any other
  85    --    routine in this unit (except Form which retrieves the original value)
  86    --
  87    --    Amethod indicates the access method
  88    --
  89    --      D = Direct_IO
  90    --      Q = Sequential_IO
  91    --      S = Stream_IO
  92    --      T = Text_IO
  93    --      W = Wide_Text_IO
  94    --
  95    --    C_Stream is left at its default value for the normal case of an
  96    --    Open or Create call as defined in the RM. The only time this is
  97    --    non-null is for the Open call from Ada.xxx_IO.C_Streams.Open.
  98    --
  99    --  On return, if the open/create succeeds, then the fields of File are
 100    --  filled in, and this value is copied to the heap. File_Ptr points to
 101    --  this allocated file control block. If the open/create fails, then the
 102    --  fields of File are undefined, and File_Ptr is unchanged.
 103
 104    procedure Close (File : in out FCB.AFCB_Ptr);
 105    --  The file is closed, all storage associated with it is released, and
 106    --  File is set to null. Note that this routine calls AFCB_Close to perform
 107    --  any specialized close actions, then closes the file at the system level,
 108    --  then frees the mode and form strings, and finally calls AFCB_Free to
 109    --  free the file control block itself, setting File to null.
 110
 111    procedure Delete (File : in out FCB.AFCB_Ptr);
 112    --  The indicated file is unlinked
 113
 114    procedure Reset (File : in out FCB.AFCB_Ptr; Mode : in FCB.File_Mode);
 115    --  The file is reset, and the mode changed as indicated.
 116
 117    procedure Reset (File : in out FCB.AFCB_Ptr);
 118    --  The files is reset, and the mode is unchanged
 119
 120    function Mode (File : in FCB.AFCB_Ptr) return FCB.File_Mode;
 121    --  Returns the mode as supplied by create, open or reset
 122
 123    function Name (File : in FCB.AFCB_Ptr) return String;
 124    --  Returns the file name as supplied by Open or Create. Raises Use_Error
 125    --  if used with temporary files or standard files.
 126
 127    function Form (File : in FCB.AFCB_Ptr) return String;
 128    --  Returns the form as supplied by create, open or reset
 129    --  The string is normalized to all lower case letters.
 130
 131    function Is_Open (File : in FCB.AFCB_Ptr) return Boolean;
 132    --  Determines if file is open or not
 133
 134    ----------------------
 135    -- Utility Routines --
 136    ----------------------
 137
 138    --  Some internal routines not defined in A.8.2. These are routines which
 139    --  provide required common functionality shared by separate packages.
 140
 141    procedure Chain_File (File : FCB.AFCB_Ptr);
 142    --  Used to chain the given file into the list of open files. Normally this
 143    --  is done implicitly by Open. Chain_File is used for the spcial cases of
 144    --  the system files defined by Text_IO (stdin, stdout, stderr) which are
 145    --  not opened in the normal manner. Note that the caller is responsible
 146    --  for task lock out to protect the global data structures if this is
 147    --  necessary (it is needed for the calls from within this unit itself,
 148    --  but not required for the calls from Text_IO and Wide_Text_IO that
 149    --  are made during elaboration of the environment task).
 150
 151    procedure Check_File_Open (File : FCB.AFCB_Ptr);
 152    --  If the current file is not open, then Status_Error is raised.
 153    --  Otherwise control returns normally (with File pointing to the
 154    --  control block for the open file.
 155
 156    procedure Check_Read_Status (File : FCB.AFCB_Ptr);
 157    --  If the current file is not open, then Status_Error is raised. If
 158    --  the file is open, then the mode is checked to ensure that reading
 159    --  is permitted, and if not Mode_Error is raised, otherwise control
 160    --  returns normally.
 161
 162    procedure Check_Write_Status (File : FCB.AFCB_Ptr);
 163    --  If the current file is not open, then Status_Error is raised. If
 164    --  the file is open, then the mode is checked to ensure that writing
 165    --  is permitted, and if not Mode_Error is raised, otherwise control
 166    --  returns normally.
 167
 168    function End_Of_File (File : FCB.AFCB_Ptr) return Boolean;
 169    --  File must be opened in read mode. True is returned if the stream is
 170    --  currently positioned at the end of file, otherwise False is returned.
 171    --  The position of the stream is not affected.
 172
 173    procedure Flush (File : FCB.AFCB_Ptr);
 174    --  Flushes the stream associated with the given file. The file must be
 175    --  open and in write mode (if not, an appropriate exception is raised)
 176
 177    function Form_Boolean
 178      (Form    : String;
 179       Keyword : String;
 180       Default : Boolean)
 181       return    Boolean;
 182    --  Searches form string for an entry of the form Keyword=xx where xx is
 183    --  either Yes/No or y/n. Returns True if Yes or Y is found, False if No
 184    --  or N is found. If the keyword parameter is not found, returns the
 185    --  value given as Default. May raise Use_Error if a form string syntax
 186    --  error is detected. Keyword and Form must be in lower case.
 187
 188    function Form_Integer
 189      (Form    : String;
 190       Keyword : String;
 191       Default : Integer)
 192       return    Integer;
 193    --  Searches form string for an entry of the form Keyword=xx where xx is
 194    --  an unsigned decimal integer in the range 0 to 999_999. Returns this
 195    --  integer value if it is found. If the keyword parameter is not found,
 196    --  returns the value given as Default. Raise Use_Error if a form string
 197    --  syntax error is detected. Keyword and Form must be in lower case.
 198
 199    procedure Form_Parameter
 200      (Form    : String;
 201       Keyword : String;
 202       Start   : out Natural;
 203       Stop    : out Natural);
 204    --  Searches form string for an entry of the form Keyword=xx and if found
 205    --  Sets Start and Stop to the first and last characters of xx. Keyword
 206    --  and Form must be in lower case. If no entry matches, then Start and
 207    --  Stop are set to zero on return. Use_Error is raised if a malformed
 208    --  string is detected, but there is no guarantee of full syntax checking.
 209
 210    procedure Read_Buf
 211      (File : FCB.AFCB_Ptr;
 212       Buf  : Address;
 213       Siz  : Interfaces.C_Streams.size_t);
 214    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 215    --  that the file is open in read mode. Raises an exception if Siz bytes
 216    --  cannot be read (End_Error if no data was read, Data_Error if a partial
 217    --  buffer was read, Device_Error if an error occurs).
 218
 219    procedure Read_Buf
 220      (File  : FCB.AFCB_Ptr;
 221       Buf   : Address;
 222       Siz   : in Interfaces.C_Streams.size_t;
 223       Count : out Interfaces.C_Streams.size_t);
 224    --  Reads Siz bytes from File.Stream into Buf. The caller has checked
 225    --  that the file is open in read mode. Device Error is raised if an error
 226    --  occurs. Count is the actual number of bytes read, which may be less
 227    --  than Siz if the end of file is encountered.
 228
 229    procedure Append_Set (File : FCB.AFCB_Ptr);
 230    --  If the mode of the file is Append_File, then the file is positioned
 231    --  at the end of file using fseek, otherwise this call has no effect.
 232
 233    procedure Write_Buf
 234      (File : FCB.AFCB_Ptr;
 235       Buf  : Address;
 236       Siz  : Interfaces.C_Streams.size_t);
 237    --  Writes size_t bytes to File.Stream from Buf. The caller has checked
 238    --  that the file is open in write mode. Raises Device_Error if the
 239    --  complete buffer cannot be written.
 240
 241    procedure Make_Unbuffered (File : FCB.AFCB_Ptr);
 242
 243    procedure Make_Line_Buffered
 244      (File     : FCB.AFCB_Ptr;
 245       Line_Siz : Interfaces.C_Streams.size_t);
 246
 247    procedure Make_Buffered
 248      (File     : FCB.AFCB_Ptr;
 249       Buf_Siz  : Interfaces.C_Streams.size_t);
 250
 251 private
 252    pragma Inline (Check_Read_Status);
 253    pragma Inline (Check_Write_Status);
 254    pragma Inline (Form);
 255    pragma Inline (Mode);
 256
 257 end System.File_IO;