gcc/ada/libgnat/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) 1996-2017, 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 with Ada.Unchecked_Conversion;
  33
  34 package body Interfaces.C_Streams is
  35
  36    use type System.CRTL.size_t;
  37
  38    ----------------------------
  39    -- Interfaced C functions --
  40    ----------------------------
  41
  42    function C_fread
  43      (buffer : voids;
  44       size   : size_t;
  45       count  : size_t;
  46       stream : FILEs) return size_t;
  47    pragma Import (C, C_fread, "fread");
  48
  49    function C_fwrite
  50      (buffer : voids;
  51       size   : size_t;
  52       count  : size_t;
  53       stream : FILEs) return size_t;
  54    pragma Import (C, C_fwrite, "fwrite");
  55
  56    function C_setvbuf
  57      (stream : FILEs;
  58       buffer : chars;
  59       mode   : int;
  60       size   : size_t) return int;
  61    pragma Import (C, C_setvbuf, "setvbuf");
  62
  63    ------------
  64    -- fread --
  65    ------------
  66
  67    function fread
  68      (buffer : voids;
  69       size   : size_t;
  70       count  : size_t;
  71       stream : FILEs) return size_t
  72    is
  73    begin
  74       return C_fread (buffer, size, count, stream);
  75    end fread;
  76
  77    ------------
  78    -- fread --
  79    ------------
  80
  81    --  The following declarations should really be nested within fread, but
  82    --  limitations in front end inlining make this undesirable right now ???
  83
  84    type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;
  85    --  This should really be 0 .. size_t'last, but there is a problem
  86    --  in gigi in handling such types (introduced in GCC 3 Sep 2001)
  87    --  since the size in bytes of this array overflows ???
  88
  89    type Acc_Bytes is access all Byte_Buffer;
  90
  91    function To_Acc_Bytes is new Ada.Unchecked_Conversion (voids, Acc_Bytes);
  92
  93    function fread
  94      (buffer : voids;
  95       index  : size_t;
  96       size   : size_t;
  97       count  : size_t;
  98       stream : FILEs) return size_t
  99    is
 100    begin
 101       return C_fread
 102         (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);
 103    end fread;
 104
 105    ------------
 106    -- fwrite --
 107    ------------
 108
 109    function fwrite
 110      (buffer : voids;
 111       size   : size_t;
 112       count  : size_t;
 113       stream : FILEs) return size_t
 114    is
 115    begin
 116       return C_fwrite (buffer, size, count, stream);
 117    end fwrite;
 118
 119    -------------
 120    -- setvbuf --
 121    -------------
 122
 123    function setvbuf
 124      (stream : FILEs;
 125       buffer : chars;
 126       mode   : int;
 127       size   : size_t) return int
 128    is
 129    begin
 130       return C_setvbuf (stream, buffer, mode, size);
 131    end setvbuf;
 132
 133 end Interfaces.C_Streams;