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

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             S I N P U T . C                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --

-- http://www.gnu.org/licenses for a complete copy of the license.          --

--                                                                          --

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

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

--                                                                          --

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

with Opt;    use Opt;

with System; use System;

with Ada.Unchecked_Conversion;

with System.OS_Lib; use System.OS_Lib;

package body Sinput.C is

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

   -- Load_File --

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

   function Load_File (Path : String) return Source_File_Index is

      Src  : Source_Buffer_Ptr;

      X    : Source_File_Index;

      Lo   : Source_Ptr;

      Hi   : Source_Ptr;

      Source_File_FD : File_Descriptor;

      --  The file descriptor for the current source file. A negative value

      --  indicates failure to open the specified source file.

      Len : Integer;

      --  Length of file. Assume no more than 2 gigabytes of source!

      Actual_Len : Integer;

      Path_Id : File_Name_Type;

      File_Id : File_Name_Type;

   begin

      if Path = "" then

         return No_Source_File;

      end if;

      Source_File.Increment_Last;

      X := Source_File.Last;

      if X = Source_File.First then

         Lo := First_Source_Ptr;

      else

         Lo := Source_File.Table (X - 1).Source_Last + 1;

      end if;

      Name_Len := Path'Length;

      Name_Buffer (1 .. Name_Len) := Path;

      Path_Id := Name_Find;

      Name_Buffer (Name_Len + 1) := ASCII.NUL;

      --  Open the source FD, note that we open in binary mode, because as

      --  documented in the spec, the caller is expected to handle either

      --  DOS or Unix mode files, and there is no point in wasting time on

      --  text translation when it is not required.

      Source_File_FD := Open_Read (Name_Buffer'Address, Binary);

      if Source_File_FD = Invalid_FD then

         Source_File.Decrement_Last;

         return No_Source_File;

      end if;

      Len := Integer (File_Length (Source_File_FD));

      --  Set Hi so that length is one more than the physical length,

      --  allowing for the extra EOF character at the end of the buffer

      Hi := Lo + Source_Ptr (Len);

      --  Do the actual read operation

      declare

         subtype Actual_Source_Buffer is Source_Buffer (Lo .. Hi);

         --  Physical buffer allocated

         type Actual_Source_Ptr is access Actual_Source_Buffer;

         --  This is the pointer type for the physical buffer allocated

         Actual_Ptr : constant Actual_Source_Ptr := new Actual_Source_Buffer;

         --  And this is the actual physical buffer

      begin

         --  Allocate source buffer, allowing extra character at end for EOF

         --  Some systems (e.g. VMS) have file types that require one

         --  read per line, so read until we get the Len bytes or until

         --  there are no more characters.

         Hi := Lo;

         loop

            Actual_Len := Read (Source_File_FD, Actual_Ptr (Hi)'Address, Len);

            Hi := Hi + Source_Ptr (Actual_Len);

            exit when Actual_Len = Len or else Actual_Len <= 0;

         end loop;

         Actual_Ptr (Hi) := EOF;

         --  Now we need to work out the proper virtual origin pointer to

         --  return. This is exactly Actual_Ptr (0)'Address, but we have

         --  to be careful to suppress checks to compute this address.

         declare

            pragma Suppress (All_Checks);

            pragma Warnings (Off);

            --  The following unchecked conversion is aliased safe, since it

            --  is not used to create improperly aliased pointer values.

            function To_Source_Buffer_Ptr is new

              Ada.Unchecked_Conversion (Address, Source_Buffer_Ptr);

            pragma Warnings (On);

         begin

            Src := To_Source_Buffer_Ptr (Actual_Ptr (0)'Address);

         end;

      end;

      --  Read is complete, close the file and we are done (no need to test

      --  status from close, since we have successfully read the file!)

      Close (Source_File_FD);

      --  Get the file name, without path information

      declare

         Index : Positive := Path'Last;

      begin

         while Index > Path'First loop

            exit when Path (Index - 1) = '/';

            exit when Path (Index - 1) = Directory_Separator;

            Index := Index - 1;

         end loop;

         Name_Len := Path'Last - Index + 1;

         Name_Buffer (1 .. Name_Len) := Path (Index .. Path'Last);

         File_Id := Name_Find;

      end;

      declare

         S : Source_File_Record renames Source_File.Table (X);

      begin

         S := (Debug_Source_Name   => File_Id,

               File_Name           => File_Id,

               File_Type           => Config,

               First_Mapped_Line   => No_Line_Number,

               Full_Debug_Name     => Path_Id,

               Full_File_Name      => Path_Id,

               Full_Ref_Name       => Path_Id,

               Identifier_Casing   => Unknown,

               Inlined_Body        => False,

               Instantiation       => No_Location,

               Keyword_Casing      => Unknown,

               Last_Source_Line    => 1,

               License             => Unknown,

               Lines_Table         => null,

               Lines_Table_Max     => 1,

               Logical_Lines_Table => null,

               Num_SRef_Pragmas    => 0,

               Reference_Name      => File_Id,

               Sloc_Adjust         => 0,

               Source_Checksum     => 0,

               Source_First        => Lo,

               Source_Last         => Hi,

               Source_Text         => Src,

               Template            => No_Source_File,

               Unit                => No_Unit,

               Time_Stamp          => Empty_Time_Stamp);

         Alloc_Line_Tables (S, Opt.Table_Factor * Alloc.Lines_Initial);

         S.Lines_Table (1) := Lo;

      end;

      Set_Source_File_Index_Table (X);

      return X;

   end Load_File;

end Sinput.C;