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

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--           G N A T . S E R I A L _ C O M M U N I C A T I O N S            --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--                    Copyright (C) 2007-2010, 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.      --

--                                                                          --

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

--  This is the GNU/Linux implementation of this package

with Ada.Streams;                use Ada.Streams;

with Ada;                        use Ada;

with Ada.Unchecked_Deallocation;

with System;               use System;

with System.Communication; use System.Communication;

with System.CRTL;          use System.CRTL;

with GNAT.OS_Lib; use GNAT.OS_Lib;

package body GNAT.Serial_Communications is

   use type Interfaces.C.unsigned;

   type Port_Data is new int;

   subtype unsigned is Interfaces.C.unsigned;

   subtype char is Interfaces.C.char;

   subtype unsigned_char is Interfaces.C.unsigned_char;

   function fcntl (fd : int; cmd : int; value : int) return int;

   pragma Import (C, fcntl, "fcntl");

   O_RDWR   : constant := 8#02#;

   O_NOCTTY : constant := 8#0400#;

   O_NDELAY : constant := 8#04000#;

   FNDELAY  : constant := O_NDELAY;

   F_SETFL  : constant := 4;

   TCSANOW  : constant := 0;

   TCIFLUSH : constant := 0;

   CLOCAL   : constant := 8#04000#;

   CREAD    : constant := 8#0200#;

   CSTOPB   : constant := 8#0100#;

   CRTSCTS  : constant := 8#020000000000#;

   PARENB   : constant := 8#00400#;

   PARODD   : constant := 8#01000#;

   --  c_cc indexes

   VTIME : constant := 5;

   VMIN  : constant := 6;

   C_Data_Rate : constant array (Data_Rate) of unsigned :=

                   (B1200   => 8#000011#,

                    B2400   => 8#000013#,

                    B4800   => 8#000014#,

                    B9600   => 8#000015#,

                    B19200  => 8#000016#,

                    B38400  => 8#000017#,

                    B57600  => 8#010001#,

                    B115200 => 8#010002#);

   C_Bits      : constant array (Data_Bits) of unsigned :=

                   (CS7 => 8#040#, CS8 => 8#060#);

   C_Stop_Bits : constant array (Stop_Bits_Number) of unsigned :=

                   (One => 0, Two => CSTOPB);

   C_Parity    : constant array (Parity_Check) of unsigned :=

                   (None => 0, Odd => PARENB or PARODD, Even => PARENB);

   procedure Raise_Error (Message : String; Error : Integer := Errno);

   pragma No_Return (Raise_Error);

   ----------

   -- Name --

   ----------

   function Name (Number : Positive) return Port_Name is

      N     : constant Natural := Number - 1;

      N_Img : constant String  := Natural'Image (N);

   begin

      return Port_Name ("/dev/ttyS" & N_Img (N_Img'First + 1 .. N_Img'Last));

   end Name;

   ----------

   -- Open --

   ----------

   procedure Open

     (Port : out Serial_Port;

      Name : Port_Name)

   is

      C_Name : constant String := String (Name) & ASCII.NUL;

      Res    : int;

   begin

      if Port.H = null then

         Port.H := new Port_Data;

      end if;

      Port.H.all := Port_Data (open

         (C_Name (C_Name'First)'Address, int (O_RDWR + O_NOCTTY + O_NDELAY)));

      if Port.H.all = -1 then

         Raise_Error ("open: open failed");

      end if;

      --  By default we are in blocking mode

      Res := fcntl (int (Port.H.all), F_SETFL, 0);

      if Res = -1 then

         Raise_Error ("open: fcntl failed");

      end if;

   end Open;

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

   -- Raise_Error --

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

   procedure Raise_Error (Message : String; Error : Integer := Errno) is

   begin

      raise Serial_Error with Message & " (" & Integer'Image (Error) & ')';

   end Raise_Error;

   ----------

   -- Read --

   ----------

   overriding procedure Read

     (Port   : in out Serial_Port;

      Buffer : out Stream_Element_Array;

      Last   : out Stream_Element_Offset)

   is

      Len : constant size_t := Buffer'Length;

      Res : ssize_t;

   begin

      if Port.H = null then

         Raise_Error ("read: port not opened", 0);

      end if;

      Res := read (Integer (Port.H.all), Buffer'Address, Len);

      if Res = -1 then

         Raise_Error ("read failed");

      end if;

      Last := Last_Index (Buffer'First, size_t (Res));

   end Read;

   ---------

   -- Set --

   ---------

   procedure Set

     (Port      : Serial_Port;

      Rate      : Data_Rate        := B9600;

      Bits      : Data_Bits        := CS8;

      Stop_Bits : Stop_Bits_Number := One;

      Parity    : Parity_Check     := None;

      Block     : Boolean          := True;

      Timeout   : Duration         := 10.0)

   is

      type termios is record

         c_iflag  : unsigned;

         c_oflag  : unsigned;

         c_cflag  : unsigned;

         c_lflag  : unsigned;

         c_line   : unsigned_char;

         c_cc     : Interfaces.C.char_array (0 .. 31);

         c_ispeed : unsigned;

         c_ospeed : unsigned;

      end record;

      pragma Convention (C, termios);

      function tcgetattr (fd : int; termios_p : Address) return int;

      pragma Import (C, tcgetattr, "tcgetattr");

      function tcsetattr

        (fd : int; action : int; termios_p : Address) return int;

      pragma Import (C, tcsetattr, "tcsetattr");

      function tcflush (fd : int; queue_selector : int) return int;

      pragma Import (C, tcflush, "tcflush");

      Current : termios;

      Res : int;

      pragma Warnings (Off, Res);

      --  Warnings off, since we don't always test the result

   begin

      if Port.H = null then

         Raise_Error ("set: port not opened", 0);

      end if;

      --  Get current port settings

      Res := tcgetattr (int (Port.H.all), Current'Address);

      --  Change settings now

      Current.c_cflag      := C_Data_Rate (Rate)

                                or C_Bits (Bits)

                                or C_Stop_Bits (Stop_Bits)

                                or C_Parity (Parity)

                                or CLOCAL

                                or CREAD

                                or CRTSCTS;

      Current.c_lflag      := 0;

      Current.c_iflag      := 0;

      Current.c_oflag      := 0;

      Current.c_ispeed     := Data_Rate_Value (Rate);

      Current.c_ospeed     := Data_Rate_Value (Rate);

      Current.c_cc (VMIN)  := char'Val (0);

      Current.c_cc (VTIME) := char'Val (Natural (Timeout * 10));

      --  Set port settings

      Res := tcflush (int (Port.H.all), TCIFLUSH);

      Res := tcsetattr (int (Port.H.all), TCSANOW, Current'Address);

      --  Block

      Res := fcntl (int (Port.H.all), F_SETFL, (if Block then 0 else FNDELAY));

      if Res = -1 then

         Raise_Error ("set: fcntl failed");

      end if;

   end Set;

   -----------

   -- Write --

   -----------

   overriding procedure Write

     (Port   : in out Serial_Port;

      Buffer : Stream_Element_Array)

   is

      Len : constant size_t := Buffer'Length;

      Res : ssize_t;

   begin

      if Port.H = null then

         Raise_Error ("write: port not opened", 0);

      end if;

      Res := write (int (Port.H.all), Buffer'Address, Len);

      if Res = -1 then

         Raise_Error ("write failed");

      end if;

      pragma Assert (size_t (Res) = Len);

   end Write;

   -----------

   -- Close --

   -----------

   procedure Close (Port : in out Serial_Port) is

      procedure Unchecked_Free is

        new Unchecked_Deallocation (Port_Data, Port_Data_Access);

      Res : int;

      pragma Unreferenced (Res);

   begin

      if Port.H /= null then

         Res := close (int (Port.H.all));

         Unchecked_Free (Port.H);

      end if;

   end Close;

end GNAT.Serial_Communications;