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 --                            $Revision: 1.1 $
  10 --                                                                          --
  11 --          Copyright (C) 1996-2001 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  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 --  This is the default version which just calls the C versions directly
  37 --  Note: the reason that we provide for specialization here is that on
  38 --  some systems, notably VMS, we may need to worry about buffering.
  39
  40 with Unchecked_Conversion;
  41
  42 package body Interfaces.C_Streams is
  43
  44    ------------
  45    -- fread --
  46    ------------
  47
  48    function fread
  49      (buffer : voids;
  50       size   : size_t;
  51       count  : size_t;
  52       stream : FILEs)
  53       return   size_t
  54    is
  55       function C_fread
  56         (buffer : voids;
  57          size   : size_t;
  58          count  : size_t;
  59          stream : FILEs)
  60          return   size_t;
  61       pragma Import (C, C_fread, "fread");
  62
  63    begin
  64       return C_fread (buffer, size, count, stream);
  65    end fread;
  66
  67    ------------
  68    -- fread --
  69    ------------
  70
  71    function fread
  72      (buffer : voids;
  73       index  : size_t;
  74       size   : size_t;
  75       count  : size_t;
  76       stream : FILEs)
  77       return   size_t
  78    is
  79       function C_fread
  80         (buffer : voids;
  81          size   : size_t;
  82          count  : size_t;
  83          stream : FILEs)
  84          return   size_t;
  85       pragma Import (C, C_fread, "fread");
  86
  87       type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;
  88       --  This should really be 0 .. size_t'last, but there is a problem
  89       --  in gigi in handling such types (introduced in GCC 3 Sep 2001)
  90       --  since the size in bytes of this array overflows ???
  91
  92       type Acc_Bytes is access all Byte_Buffer;
  93
  94       function To_Acc_Bytes is new Unchecked_Conversion (voids, Acc_Bytes);
  95
  96    begin
  97       return C_fread
  98         (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);
  99    end fread;
 100
 101    ------------
 102    -- fwrite --
 103    ------------
 104
 105    function fwrite
 106      (buffer : voids;
 107       size   : size_t;
 108       count  : size_t;
 109       stream : FILEs)
 110       return   size_t
 111    is
 112       function C_fwrite
 113         (buffer : voids;
 114          size   : size_t;
 115          count  : size_t;
 116          stream : FILEs)
 117          return   size_t;
 118       pragma Import (C, C_fwrite, "fwrite");
 119
 120    begin
 121       return C_fwrite (buffer, size, count, stream);
 122    end fwrite;
 123
 124    -------------
 125    -- setvbuf --
 126    -------------
 127
 128    function setvbuf
 129      (stream : FILEs;
 130       buffer : chars;
 131       mode   : int;
 132       size   : size_t)
 133       return   int
 134    is
 135       function C_setvbuf
 136         (stream : FILEs;
 137          buffer : chars;
 138          mode   : int;
 139          size   : size_t)
 140          return   int;
 141       pragma Import (C, C_setvbuf, "setvbuf");
 142
 143    begin
 144       return C_setvbuf (stream, buffer, mode, size);
 145    end setvbuf;
 146
 147 end Interfaces.C_Streams;