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) 1996-2009, 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is the default version which just calls the C versions directly
  33 --  Note: the reason that we provide for specialization here is that on
  34 --  some systems, notably VMS, we may need to worry about buffering.
  35
  36 with Ada.Unchecked_Conversion;
  37
  38 package body Interfaces.C_Streams is
  39
  40    use type System.CRTL.size_t;
  41
  42    ----------------------------
  43    -- Interfaced C functions --
  44    ----------------------------
  45
  46    function C_fread
  47      (buffer : voids;
  48       size   : size_t;
  49       count  : size_t;
  50       stream : FILEs) return size_t;
  51    pragma Import (C, C_fread, "fread");
  52
  53    function C_fwrite
  54      (buffer : voids;
  55       size   : size_t;
  56       count  : size_t;
  57       stream : FILEs) return size_t;
  58    pragma Import (C, C_fwrite, "fwrite");
  59
  60    function C_setvbuf
  61      (stream : FILEs;
  62       buffer : chars;
  63       mode   : int;
  64       size   : size_t) return int;
  65    pragma Import (C, C_setvbuf, "setvbuf");
  66
  67    ------------
  68    -- fread --
  69    ------------
  70
  71    function fread
  72      (buffer : voids;
  73       size   : size_t;
  74       count  : size_t;
  75       stream : FILEs) return size_t
  76    is
  77    begin
  78       return C_fread (buffer, size, count, stream);
  79    end fread;
  80
  81    ------------
  82    -- fread --
  83    ------------
  84
  85    --  The following declarations should really be nested within fread, but
  86    --  limitations in front end inlining make this undesirable right now ???
  87
  88    type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;
  89    --  This should really be 0 .. size_t'last, but there is a problem
  90    --  in gigi in handling such types (introduced in GCC 3 Sep 2001)
  91    --  since the size in bytes of this array overflows ???
  92
  93    type Acc_Bytes is access all Byte_Buffer;
  94
  95    function To_Acc_Bytes is new Ada.Unchecked_Conversion (voids, Acc_Bytes);
  96
  97    function fread
  98      (buffer : voids;
  99       index  : size_t;
 100       size   : size_t;
 101       count  : size_t;
 102       stream : FILEs) return size_t
 103    is
 104    begin
 105       return C_fread
 106         (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);
 107    end fread;
 108
 109    ------------
 110    -- fwrite --
 111    ------------
 112
 113    function fwrite
 114      (buffer : voids;
 115       size   : size_t;
 116       count  : size_t;
 117       stream : FILEs) return size_t
 118    is
 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) return int
 132    is
 133    begin
 134       return C_setvbuf (stream, buffer, mode, size);
 135    end setvbuf;
 136
 137 end Interfaces.C_Streams;