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 --          Copyright (C) 1996-2001 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 is the default version which just calls the C versions directly
  35 --  Note: the reason that we provide for specialization here is that on
  36 --  some systems, notably VMS, we may need to worry about buffering.
  37
  38 with Unchecked_Conversion;
  39
  40 package body Interfaces.C_Streams is
  41
  42    ------------
  43    -- fread --
  44    ------------
  45
  46    function fread
  47      (buffer : voids;
  48       size   : size_t;
  49       count  : size_t;
  50       stream : FILEs)
  51       return   size_t
  52    is
  53       function C_fread
  54         (buffer : voids;
  55          size   : size_t;
  56          count  : size_t;
  57          stream : FILEs)
  58          return   size_t;
  59       pragma Import (C, C_fread, "fread");
  60
  61    begin
  62       return C_fread (buffer, size, count, stream);
  63    end fread;
  64
  65    ------------
  66    -- fread --
  67    ------------
  68
  69    function fread
  70      (buffer : voids;
  71       index  : size_t;
  72       size   : size_t;
  73       count  : size_t;
  74       stream : FILEs)
  75       return   size_t
  76    is
  77       function C_fread
  78         (buffer : voids;
  79          size   : size_t;
  80          count  : size_t;
  81          stream : FILEs)
  82          return   size_t;
  83       pragma Import (C, C_fread, "fread");
  84
  85       type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;
  86       --  This should really be 0 .. size_t'last, but there is a problem
  87       --  in gigi in handling such types (introduced in GCC 3 Sep 2001)
  88       --  since the size in bytes of this array overflows ???
  89
  90       type Acc_Bytes is access all Byte_Buffer;
  91
  92       function To_Acc_Bytes is new Unchecked_Conversion (voids, Acc_Bytes);
  93
  94    begin
  95       return C_fread
  96         (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);
  97    end fread;
  98
  99    ------------
 100    -- fwrite --
 101    ------------
 102
 103    function fwrite
 104      (buffer : voids;
 105       size   : size_t;
 106       count  : size_t;
 107       stream : FILEs)
 108       return   size_t
 109    is
 110       function C_fwrite
 111         (buffer : voids;
 112          size   : size_t;
 113          count  : size_t;
 114          stream : FILEs)
 115          return   size_t;
 116       pragma Import (C, C_fwrite, "fwrite");
 117
 118    begin
 119       return C_fwrite (buffer, size, count, stream);
 120    end fwrite;
 121
 122    -------------
 123    -- setvbuf --
 124    -------------
 125
 126    function setvbuf
 127      (stream : FILEs;
 128       buffer : chars;
 129       mode   : int;
 130       size   : size_t)
 131       return   int
 132    is
 133       function C_setvbuf
 134         (stream : FILEs;
 135          buffer : chars;
 136          mode   : int;
 137          size   : size_t)
 138          return   int;
 139       pragma Import (C, C_setvbuf, "setvbuf");
 140
 141    begin
 142       return C_setvbuf (stream, buffer, mode, size);
 143    end setvbuf;
 144
 145 end Interfaces.C_Streams;