gcc/ada/i-cstrea.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                 I N T E R F A C E S . C _ S T R E A M S                  --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1996-2001 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 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 --  This is the default version which just calls the C versions directly
  36 --  Note: the reason that we provide for specialization here is that on
  37 --  some systems, notably VMS, we may need to worry about buffering.
  38
  39 with Unchecked_Conversion;
  40
  41 package body Interfaces.C_Streams is
  42
  43    ------------
  44    -- fread --
  45    ------------
  46
  47    function fread
  48      (buffer : voids;
  49       size   : size_t;
  50       count  : size_t;
  51       stream : FILEs)
  52       return   size_t
  53    is
  54       function C_fread
  55         (buffer : voids;
  56          size   : size_t;
  57          count  : size_t;
  58          stream : FILEs)
  59          return   size_t;
  60       pragma Import (C, C_fread, "fread");
  61
  62    begin
  63       return C_fread (buffer, size, count, stream);
  64    end fread;
  65
  66    ------------
  67    -- fread --
  68    ------------
  69
  70    function fread
  71      (buffer : voids;
  72       index  : size_t;
  73       size   : size_t;
  74       count  : size_t;
  75       stream : FILEs)
  76       return   size_t
  77    is
  78       function C_fread
  79         (buffer : voids;
  80          size   : size_t;
  81          count  : size_t;
  82          stream : FILEs)
  83          return   size_t;
  84       pragma Import (C, C_fread, "fread");
  85
  86       type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;
  87       --  This should really be 0 .. size_t'last, but there is a problem
  88       --  in gigi in handling such types (introduced in GCC 3 Sep 2001)
  89       --  since the size in bytes of this array overflows ???
  90
  91       type Acc_Bytes is access all Byte_Buffer;
  92
  93       function To_Acc_Bytes is new Unchecked_Conversion (voids, Acc_Bytes);
  94
  95    begin
  96       return C_fread
  97         (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);
  98    end fread;
  99
 100    ------------
 101    -- fwrite --
 102    ------------
 103
 104    function fwrite
 105      (buffer : voids;
 106       size   : size_t;
 107       count  : size_t;
 108       stream : FILEs)
 109       return   size_t
 110    is
 111       function C_fwrite
 112         (buffer : voids;
 113          size   : size_t;
 114          count  : size_t;
 115          stream : FILEs)
 116          return   size_t;
 117       pragma Import (C, C_fwrite, "fwrite");
 118
 119    begin
 120       return C_fwrite (buffer, size, count, stream);
 121    end fwrite;
 122
 123    -------------
 124    -- setvbuf --
 125    -------------
 126
 127    function setvbuf
 128      (stream : FILEs;
 129       buffer : chars;
 130       mode   : int;
 131       size   : size_t)
 132       return   int
 133    is
 134       function C_setvbuf
 135         (stream : FILEs;
 136          buffer : chars;
 137          mode   : int;
 138          size   : size_t)
 139          return   int;
 140       pragma Import (C, C_setvbuf, "setvbuf");
 141
 142    begin
 143       return C_setvbuf (stream, buffer, mode, size);
 144    end setvbuf;
 145
 146 end Interfaces.C_Streams;