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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                 I N T E R F A C E S . C _ S T R E A M S                  --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1996-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  This is the default version which just calls the C versions directly

--  Note: the reason that we provide for specialization here is that on

--  some systems, notably VMS, we may need to worry about buffering.

with Ada.Unchecked_Conversion;

package body Interfaces.C_Streams is

   use type System.CRTL.size_t;

   ----------------------------

   -- Interfaced C functions --

   ----------------------------

   function C_fread

     (buffer : voids;

      size   : size_t;

      count  : size_t;

      stream : FILEs) return size_t;

   pragma Import (C, C_fread, "fread");

   function C_fwrite

     (buffer : voids;

      size   : size_t;

      count  : size_t;

      stream : FILEs) return size_t;

   pragma Import (C, C_fwrite, "fwrite");

   function C_setvbuf

     (stream : FILEs;

      buffer : chars;

      mode   : int;

      size   : size_t) return int;

   pragma Import (C, C_setvbuf, "setvbuf");

   ------------

   -- fread --

   ------------

   function fread

     (buffer : voids;

      size   : size_t;

      count  : size_t;

      stream : FILEs) return size_t

   is

   begin

      return C_fread (buffer, size, count, stream);

   end fread;

   ------------

   -- fread --

   ------------

   --  The following declarations should really be nested within fread, but

   --  limitations in front end inlining make this undesirable right now ???

   type Byte_Buffer is array (0 .. size_t'Last / 2 - 1) of Unsigned_8;

   --  This should really be 0 .. size_t'last, but there is a problem

   --  in gigi in handling such types (introduced in GCC 3 Sep 2001)

   --  since the size in bytes of this array overflows ???

   type Acc_Bytes is access all Byte_Buffer;

   function To_Acc_Bytes is new Ada.Unchecked_Conversion (voids, Acc_Bytes);

   function fread

     (buffer : voids;

      index  : size_t;

      size   : size_t;

      count  : size_t;

      stream : FILEs) return size_t

   is

   begin

      return C_fread

        (To_Acc_Bytes (buffer) (index * size)'Address, size, count, stream);

   end fread;

   ------------

   -- fwrite --

   ------------

   function fwrite

     (buffer : voids;

      size   : size_t;

      count  : size_t;

      stream : FILEs) return size_t

   is

   begin

      return C_fwrite (buffer, size, count, stream);

   end fwrite;

   -------------

   -- setvbuf --

   -------------

   function setvbuf

     (stream : FILEs;

      buffer : chars;

      mode   : int;

      size   : size_t) return int

   is

   begin

      return C_setvbuf (stream, buffer, mode, size);

   end setvbuf;

end Interfaces.C_Streams;