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

--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                          G N A T . I O _ A U X                           --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--                     Copyright (C) 1995-2010, AdaCore                     --

--                                                                          --

-- 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.      --

--                                                                          --

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

with Interfaces.C_Streams; use Interfaces.C_Streams;

package body GNAT.IO_Aux is

   Buflen : constant := 2000;

   --  Buffer length. Works for any non-zero value, larger values take

   --  more stack space, smaller values require more recursion.

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

   -- File_Exists --

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

   function File_Exists (Name : String) return Boolean

   is

      Namestr : aliased String (1 .. Name'Length + 1);

      --  Name as given with ASCII.NUL appended

   begin

      Namestr (1 .. Name'Length) := Name;

      Namestr (Name'Length + 1)  := ASCII.NUL;

      return file_exists (Namestr'Address) /= 0;

   end File_Exists;

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

   -- Get_Line --

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

   --  Current_Input case

   function Get_Line return String is

      Buffer : String (1 .. Buflen);

      --  Buffer to read in chunks of remaining line. Will work with any

      --  size buffer. We choose a length so that most of the time no

      --  recursion will be required.

      Last : Natural;

   begin

      Ada.Text_IO.Get_Line (Buffer, Last);

      --  If the buffer is not full, then we are all done

      if Last < Buffer'Last then

         return Buffer (1 .. Last);

      --  Otherwise, we still have characters left on the line. Note that

      --  as specified by (RM A.10.7(19)) the end of line is not skipped

      --  in this case, even if we are right at it now.

      else

         return Buffer & GNAT.IO_Aux.Get_Line;

      end if;

   end Get_Line;

   --  Case of reading from a specified file. Note that we could certainly

   --  share code between these two versions, but these are very short

   --  routines, and we may as well aim for maximum speed, cutting out an

   --  intermediate call (calls returning string may be somewhat slow)

   function Get_Line (File : Ada.Text_IO.File_Type) return String is

      Buffer : String (1 .. Buflen);

      Last   : Natural;

   begin

      Ada.Text_IO.Get_Line (File, Buffer, Last);

      if Last < Buffer'Last then

         return Buffer (1 .. Last);

      else

         return Buffer & Get_Line (File);

      end if;

   end Get_Line;

end GNAT.IO_Aux;