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

--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                A D A . S T R E A M S . S T R E A M _ I O                 --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2010, 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.      --

--                                                                          --

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

with Interfaces.C_Streams; use Interfaces.C_Streams;

with System;               use System;

with System.Communication; use System.Communication;

with System.File_IO;

with System.Soft_Links;

with System.CRTL;

with Ada.Unchecked_Conversion;

with Ada.Unchecked_Deallocation;

package body Ada.Streams.Stream_IO is

   package FIO renames System.File_IO;

   package SSL renames System.Soft_Links;

   subtype AP is FCB.AFCB_Ptr;

   function To_FCB is new Ada.Unchecked_Conversion (File_Mode, FCB.File_Mode);

   function To_SIO is new Ada.Unchecked_Conversion (FCB.File_Mode, File_Mode);

   use type FCB.File_Mode;

   use type FCB.Shared_Status_Type;

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

   -- Local Subprograms --

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

   procedure Set_Position (File : File_Type);

   --  Sets file position pointer according to value of current index

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

   -- AFCB_Allocate --

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

   function AFCB_Allocate (Control_Block : Stream_AFCB) return FCB.AFCB_Ptr is

      pragma Warnings (Off, Control_Block);

   begin

      return new Stream_AFCB;

   end AFCB_Allocate;

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

   -- AFCB_Close --

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

   --  No special processing required for closing Stream_IO file

   procedure AFCB_Close (File : not null access Stream_AFCB) is

      pragma Warnings (Off, File);

   begin

      null;

   end AFCB_Close;

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

   -- AFCB_Free --

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

   procedure AFCB_Free (File : not null access Stream_AFCB) is

      type FCB_Ptr is access all Stream_AFCB;

      FT : FCB_Ptr := FCB_Ptr (File);

      procedure Free is new Ada.Unchecked_Deallocation (Stream_AFCB, FCB_Ptr);

   begin

      Free (FT);

   end AFCB_Free;

   -----------

   -- Close --

   -----------

   procedure Close (File : in out File_Type) is

   begin

      FIO.Close (AP (File)'Unrestricted_Access);

   end Close;

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

   -- Create --

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

   procedure Create

     (File : in out File_Type;

      Mode : File_Mode := Out_File;

      Name : String := "";

      Form : String := "")

   is

      Dummy_File_Control_Block : Stream_AFCB;

      pragma Warnings (Off, Dummy_File_Control_Block);

      --  Yes, we know this is never assigned a value, only the tag

      --  is used for dispatching purposes, so that's expected.

   begin

      FIO.Open (File_Ptr  => AP (File),

                Dummy_FCB => Dummy_File_Control_Block,

                Mode      => To_FCB (Mode),

                Name      => Name,

                Form      => Form,

                Amethod   => 'S',

                Creat     => True,

                Text      => False);

      File.Last_Op := Op_Write;

   end Create;

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

   -- Delete --

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

   procedure Delete (File : in out File_Type) is

   begin

      FIO.Delete (AP (File)'Unrestricted_Access);

   end Delete;

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

   -- End_Of_File --

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

   function End_Of_File (File : File_Type) return Boolean is

   begin

      FIO.Check_Read_Status (AP (File));

      return File.Index > Size (File);

   end End_Of_File;

   -----------

   -- Flush --

   -----------

   procedure Flush (File : File_Type) is

   begin

      FIO.Flush (AP (File));

   end Flush;

   ----------

   -- Form --

   ----------

   function Form (File : File_Type) return String is

   begin

      return FIO.Form (AP (File));

   end Form;

   -----------

   -- Index --

   -----------

   function Index (File : File_Type) return Positive_Count is

   begin

      FIO.Check_File_Open (AP (File));

      return File.Index;

   end Index;

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

   -- Is_Open --

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

   function Is_Open (File : File_Type) return Boolean is

   begin

      return FIO.Is_Open (AP (File));

   end Is_Open;

   ----------

   -- Mode --

   ----------

   function Mode (File : File_Type) return File_Mode is

   begin

      return To_SIO (FIO.Mode (AP (File)));

   end Mode;

   ----------

   -- Name --

   ----------

   function Name (File : File_Type) return String is

   begin

      return FIO.Name (AP (File));

   end Name;

   ----------

   -- Open --

   ----------

   procedure Open

     (File : in out File_Type;

      Mode : File_Mode;

      Name : String;

      Form : String := "")

   is

      Dummy_File_Control_Block : Stream_AFCB;

      pragma Warnings (Off, Dummy_File_Control_Block);

      --  Yes, we know this is never assigned a value, only the tag

      --  is used for dispatching purposes, so that's expected.

   begin

      FIO.Open (File_Ptr  => AP (File),

                Dummy_FCB => Dummy_File_Control_Block,

                Mode      => To_FCB (Mode),

                Name      => Name,

                Form      => Form,

                Amethod   => 'S',

                Creat     => False,

                Text      => False);

      --  Ensure that the stream index is set properly (e.g., for Append_File)

      Reset (File, Mode);

      --  Set last operation. The purpose here is to ensure proper handling

      --  of the initial operation. In general, a write after a read requires

      --  resetting and doing a seek, so we set the last operation as Read

      --  for an In_Out file, but for an Out file we set the last operation

      --  to Op_Write, since in this case it is not necessary to do a seek

      --  (and furthermore there are situations (such as the case of writing

      --  a sequential Posix FIFO file) where the lseek would cause problems.

      File.Last_Op := (if Mode = Out_File then Op_Write else Op_Read);

   end Open;

   ----------

   -- Read --

   ----------

   procedure Read

     (File : File_Type;

      Item : out Stream_Element_Array;

      Last : out Stream_Element_Offset;

      From : Positive_Count)

   is

   begin

      Set_Index (File, From);

      Read (File, Item, Last);

   end Read;

   procedure Read

     (File : File_Type;

      Item : out Stream_Element_Array;

      Last : out Stream_Element_Offset)

   is

      Nread : size_t;

   begin

      FIO.Check_Read_Status (AP (File));

      --  If last operation was not a read, or if in file sharing mode,

      --  then reset the physical pointer of the file to match the index

      --  We lock out task access over the two operations in this case.

      if File.Last_Op /= Op_Read

        or else File.Shared_Status = FCB.Yes

      then

         Locked_Processing : begin

            SSL.Lock_Task.all;

            Set_Position (File);

            FIO.Read_Buf (AP (File), Item'Address, Item'Length, Nread);

            SSL.Unlock_Task.all;

         exception

            when others =>

               SSL.Unlock_Task.all;

               raise;

         end Locked_Processing;

      else

         FIO.Read_Buf (AP (File), Item'Address, Item'Length, Nread);

      end if;

      File.Index := File.Index + Count (Nread);

      File.Last_Op := Op_Read;

      Last := Last_Index (Item'First, Nread);

   end Read;

   --  This version of Read is the primitive operation on the underlying

   --  Stream type, used when a Stream_IO file is treated as a Stream

   procedure Read

     (File : in out Stream_AFCB;

      Item : out Ada.Streams.Stream_Element_Array;

      Last : out Ada.Streams.Stream_Element_Offset)

   is

   begin

      Read (File'Unchecked_Access, Item, Last);

   end Read;

   -----------

   -- Reset --

   -----------

   procedure Reset (File : in out File_Type; Mode : File_Mode) is

   begin

      FIO.Check_File_Open (AP (File));

      --  Reset file index to start of file for read/write cases. For

      --  the append case, the Set_Mode call repositions the index.

      File.Index := 1;

      Set_Mode (File, Mode);

   end Reset;

   procedure Reset (File : in out File_Type) is

   begin

      Reset (File, To_SIO (File.Mode));

   end Reset;

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

   -- Set_Index --

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

   procedure Set_Index (File : File_Type; To : Positive_Count) is

   begin

      FIO.Check_File_Open (AP (File));

      File.Index := Count (To);

      File.Last_Op := Op_Other;

   end Set_Index;

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

   -- Set_Mode --

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

   procedure Set_Mode (File : in out File_Type; Mode : File_Mode) is

   begin

      FIO.Check_File_Open (AP (File));

      --  If we are switching from read to write, or vice versa, and

      --  we are not already open in update mode, then reopen in update

      --  mode now. Note that we can use Inout_File as the mode for the

      --  call since File_IO handles all modes for all file types.

      if ((File.Mode = FCB.In_File) /= (Mode = In_File))

        and then not File.Update_Mode

      then

         FIO.Reset (AP (File)'Unrestricted_Access, FCB.Inout_File);

         File.Update_Mode := True;

      end if;

      --  Set required mode and position to end of file if append mode

      File.Mode := To_FCB (Mode);

      FIO.Append_Set (AP (File));

      if File.Mode = FCB.Append_File then

         File.Index := Count (ftell (File.Stream)) + 1;

      end if;

      File.Last_Op := Op_Other;

   end Set_Mode;

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

   -- Set_Position --

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

   procedure Set_Position (File : File_Type) is

      use type System.CRTL.long;

   begin

      if fseek (File.Stream,

                System.CRTL.long (File.Index) - 1, SEEK_SET) /= 0

      then

         raise Use_Error;

      end if;

   end Set_Position;

   ----------

   -- Size --

   ----------

   function Size (File : File_Type) return Count is

   begin

      FIO.Check_File_Open (AP (File));

      if File.File_Size = -1 then

         File.Last_Op := Op_Other;

         if fseek (File.Stream, 0, SEEK_END) /= 0 then

            raise Device_Error;

         end if;

         File.File_Size := Stream_Element_Offset (ftell (File.Stream));

      end if;

      return Count (File.File_Size);

   end Size;

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

   -- Stream --

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

   function Stream (File : File_Type) return Stream_Access is

   begin

      FIO.Check_File_Open (AP (File));

      return Stream_Access (File);

   end Stream;

   -----------

   -- Write --

   -----------

   procedure Write

     (File : File_Type;

      Item : Stream_Element_Array;

      To   : Positive_Count)

   is

   begin

      Set_Index (File, To);

      Write (File, Item);

   end Write;

   procedure Write

     (File : File_Type;

      Item : Stream_Element_Array)

   is

   begin

      FIO.Check_Write_Status (AP (File));

      --  If last operation was not a write, or if in file sharing mode,

      --  then reset the physical pointer of the file to match the index

      --  We lock out task access over the two operations in this case.

      if File.Last_Op /= Op_Write

        or else File.Shared_Status = FCB.Yes

      then

         Locked_Processing : begin

            SSL.Lock_Task.all;

            Set_Position (File);

            FIO.Write_Buf (AP (File), Item'Address, Item'Length);

            SSL.Unlock_Task.all;

         exception

            when others =>

               SSL.Unlock_Task.all;

               raise;

         end Locked_Processing;

      else

         FIO.Write_Buf (AP (File), Item'Address, Item'Length);

      end if;

      File.Index := File.Index + Item'Length;

      File.Last_Op := Op_Write;

      File.File_Size := -1;

   end Write;

   --  This version of Write is the primitive operation on the underlying

   --  Stream type, used when a Stream_IO file is treated as a Stream

   procedure Write

     (File : in out Stream_AFCB;

      Item : Ada.Streams.Stream_Element_Array)

   is

   begin

      Write (File'Unchecked_Access, Item);

   end Write;

end Ada.Streams.Stream_IO;