--  GHDL Run Time (GRT) -  VHDL files subprograms.
--  Copyright (C) 2002 - 2014 Tristan Gingold
--
--  GHDL is free software; you can redistribute it and/or modify it under
--  the terms of the GNU General Public License as published by the Free
--  Software Foundation; either version 2, or (at your option) any later
--  version.
--
--  GHDL is distributed in the hope that it will be useful, but WITHOUT 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
--  along with GCC; see the file COPYING.  If not, write to the Free
--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
--  02111-1307, USA.
--
--  As a special exception, if other files instantiate generics from this
--  unit, or you link this unit with other files to produce an executable,
--  this unit does not by itself cause the resulting executable to be
--  covered by the GNU General Public License. This exception does not
--  however invalidate any other reasons why the executable file might be
--  covered by the GNU Public License.
with Grt.Errors; use Grt.Errors;
with Grt.Stdio; use Grt.Stdio;
with Grt.C; use Grt.C;
with Grt.Table;
with Grt.Options;
with System; use System;
pragma Elaborate_All (Grt.Table);

package body Grt.Files is
   subtype C_Files is Grt.Stdio.FILEs;

   Auto_Flush : constant Boolean := False;

   type File_Entry_Type is record
      Stream : C_Files;
      Signature : Ghdl_C_String;
      Is_Text : Boolean;
      Is_Alive : Boolean;
   end record;

   package Files_Table is new Grt.Table
     (Table_Component_Type => File_Entry_Type,
      Table_Index_Type => Ghdl_File_Index,
      Table_Low_Bound => 1,
      Table_Initial => 2);

   function Get_File (Index : Ghdl_File_Index) return C_Files
   is
   begin
      if Index not in Files_Table.First .. Files_Table.Last then
         Internal_Error ("get_file: bad file index");
      end if;
      return Files_Table.Table (Index).Stream;
   end Get_File;

   procedure Check_File_Mode (Index : Ghdl_File_Index; Is_Text : Boolean)
   is
   begin
      if Files_Table.Table (Index).Is_Text /= Is_Text then
         Internal_Error ("check_file_mode: bad file mode");
      end if;
   end Check_File_Mode;

   function Create_File (Is_Text : Boolean; Sig : Ghdl_C_String)
                        return Ghdl_File_Index is
   begin
      Files_Table.Append ((Stream => NULL_Stream,
                           Signature => Sig,
                           Is_Text => Is_Text,
                           Is_Alive => True));
      return Files_Table.Last;
   end Create_File;

   procedure Destroy_File (Is_Text : Boolean; Index : Ghdl_File_Index) is
   begin
      if Get_File (Index) /= NULL_Stream then
         Internal_Error ("destroy_file");
      end if;
      Check_File_Mode (Index, Is_Text);
      Files_Table.Table (Index).Is_Alive := False;
      if Index = Files_Table.Last then
         while Files_Table.Last >= Files_Table.First
           and then Files_Table.Table (Files_Table.Last).Is_Alive = False
         loop
            Files_Table.Decrement_Last;
         end loop;
      end if;
   end Destroy_File;

   procedure File_Error (File : Ghdl_File_Index)
   is
      pragma Unreferenced (File);
   begin
      Internal_Error ("file: IO error");
   end File_Error;

   function Ghdl_Text_File_Elaborate return Ghdl_File_Index is
   begin
      return Create_File (True, null);
   end Ghdl_Text_File_Elaborate;

   function Ghdl_File_Elaborate (Sig : Ghdl_C_String) return Ghdl_File_Index
   is
   begin
      return Create_File (False, Sig);
   end Ghdl_File_Elaborate;

   procedure Ghdl_Text_File_Finalize (File : Ghdl_File_Index) is
   begin
      Destroy_File (True, File);
   end Ghdl_Text_File_Finalize;

   procedure Ghdl_File_Finalize (File : Ghdl_File_Index) is
   begin
      Destroy_File (False, File);
   end Ghdl_File_Finalize;

   function Ghdl_File_Endfile (File : Ghdl_File_Index) return Boolean
   is
      Stream : C_Files;
      C : int;
   begin
      Stream := Get_File (File);
      if feof (Stream) /= 0 then
         return True;
      end if;
      C := fgetc (Stream);
      if C < 0 then
         return True;
      end if;
      if ungetc (C, Stream) /= C then
         Error ("internal error: ungetc");
      end if;
      return False;
   end Ghdl_File_Endfile;

   Sig_Header : constant String := "#GHDL-BINARY-FILE-0.0" & Nl;

   function File_Open (File : Ghdl_File_Index;
                       Mode : Ghdl_I32;
                       Str : Std_String_Ptr)
     return Ghdl_I32
   is
      Name : String (1 .. Integer (Str.Bounds.Dim_1.Length) + 1);
      Str_Mode : String (1 .. 3);
      F : C_Files;
      Sig : Ghdl_C_String;
      Sig_Len : Natural;
   begin
      F := Get_File (File);

      if F /= NULL_Stream then
         --  File was already open.
         return Status_Error;
      end if;

      --  Copy file name and convert it to a C string (NUL terminated).
      for I in 1 .. Str.Bounds.Dim_1.Length loop
         Name (Natural (I)) := Str.Base (I - 1);
      end loop;
      Name (Name'Last) := NUL;

      if Name = "STD_INPUT" & NUL then
         if Mode /= Read_Mode then
            return Mode_Error;
         end if;
         F := stdin;
      elsif Name = "STD_OUTPUT" & NUL then
         if Mode /= Write_Mode then
            return Mode_Error;
         end if;
         F := stdout;
      else
         case Mode is
            when Read_Mode =>
               Str_Mode (1) := 'r';
            when Write_Mode =>
               Str_Mode (1) := 'w';
            when Append_Mode =>
               Str_Mode (1) := 'a';
            when others =>
               --  Bad mode, cannot happen.
               Internal_Error ("file_open: bad open mode");
         end case;
         if Files_Table.Table (File).Is_Text then
            Str_Mode (2) := NUL;
         else
            Str_Mode (2) := 'b';
            Str_Mode (3) := NUL;
         end if;
         F := fopen (Name'Address, Str_Mode'Address);
         if F = NULL_Stream then
            return Name_Error;
         end if;
         if Grt.Options.Unbuffered_Writes and Mode /= Read_Mode then
            setbuf (F, NULL_voids);
         end if;
      end if;
      Sig := Files_Table.Table (File).Signature;
      if Sig /= null then
         Sig_Len := strlen (Sig);
         case Mode is
            when Write_Mode =>
               if fwrite (Sig_Header'Address, 1, Sig_Header'Length, F)
                 /= Sig_Header'Length
               then
                  File_Error (File);
               end if;
               if fwrite (Sig (1)'Address, 1, size_t (Sig_Len), F)
                 /= size_t (Sig_Len)
               then
                  File_Error (File);
               end if;
            when Read_Mode =>
               declare
                  Hdr : String (1 .. Sig_Header'Length);
                  Sig_Buf : String (1 .. Sig_Len);
               begin
                  if fread (Hdr'Address, 1, Hdr'Length, F) /= Hdr'Length then
                     File_Error (File);
                  end if;
                  if Hdr /= Sig_Header then
                     File_Error (File);
                  end if;
                  if fread (Sig_Buf'Address, 1, Sig_Buf'Length, F)
                    /= Sig_Buf'Length
                  then
                     File_Error (File);
                  end if;
                  if Sig_Buf /= Sig (1 .. Sig_Len) then
                     File_Error (File);
                  end if;
               end;
            when Append_Mode =>
               null;
            when others =>
               null;
         end case;
      end if;
      Files_Table.Table (File).Stream := F;
      return Open_Ok;
   end File_Open;

   procedure Ghdl_Text_File_Open
     (File : Ghdl_File_Index; Mode : Ghdl_I32; Str : Std_String_Ptr)
   is
      Res : Ghdl_I32;
      Bt : Backtrace_Addrs;
   begin
      Check_File_Mode (File, True);

      Res := File_Open (File, Mode, Str);

      if Res /= Open_Ok then
         Save_Backtrace (Bt, 1);
         Error_C ("cannot open text file """);
         Error_C_Std (Str.Base (0 .. Str.Bounds.Dim_1.Length - 1));
         Error_C ("""");
         Error_E_Call_Stack (Bt);
      end if;
   end Ghdl_Text_File_Open;

   procedure Ghdl_File_Open
     (File : Ghdl_File_Index; Mode : Ghdl_I32; Str : Std_String_Ptr)
   is
      Res : Ghdl_I32;
      Bt : Backtrace_Addrs;
   begin
      Check_File_Mode (File, False);

      Res := File_Open (File, Mode, Str);

      if Res /= Open_Ok then
         Save_Backtrace (Bt, 1);
         Error_C ("cannot open file """);
         Error_C_Std (Str.Base (0 .. Str.Bounds.Dim_1.Length - 1));
         Error_C ("""");
         Error_E_Call_Stack (Bt);
      end if;
   end Ghdl_File_Open;

   function Ghdl_Text_File_Open_Status
     (File : Ghdl_File_Index; Mode : Ghdl_I32; Str : Std_String_Ptr)
     return Ghdl_I32
   is
   begin
      Check_File_Mode (File, True);
      return File_Open (File, Mode, Str);
   end Ghdl_Text_File_Open_Status;

   function Ghdl_File_Open_Status
     (File : Ghdl_File_Index; Mode : Ghdl_I32; Str : Std_String_Ptr)
     return Ghdl_I32
   is
   begin
      Check_File_Mode (File, False);
      return File_Open (File, Mode, Str);
   end Ghdl_File_Open_Status;

   procedure Ghdl_Text_Write (File : Ghdl_File_Index; Str : Std_String_Ptr)
   is
      Res : C_Files;
      R : size_t;
      R1 : int;
      pragma Unreferenced (R, R1);
   begin
      Res := Get_File (File);
      Check_File_Mode (File, True);
      if Res = NULL_Stream then
         Error ("write to a non-opened file");
      end if;
      --  FIXME: check mode.
      R := fwrite (Str.Base (0)'Address,
                   size_t (Str.Bounds.Dim_1.Length), 1, Res);
      --  FIXME: check r
      if Auto_Flush then
         fflush (Res);
      end if;
   end Ghdl_Text_Write;

   procedure Ghdl_Write_Scalar (File : Ghdl_File_Index;
                                Ptr : Ghdl_Ptr;
                                Length : Ghdl_Index_Type)
   is
      Res : C_Files;
      R : size_t;
   begin
      Res := Get_File (File);
      Check_File_Mode (File, False);
      if Res = NULL_Stream then
         Error ("write to a non-opened file");
      end if;
      --  FIXME: check mode.
      R := fwrite (System.Address (Ptr), size_t (Length), 1, Res);
      if R /= 1 then
         Error ("write_scalar failed");
      end if;
      if Auto_Flush then
         fflush (Res);
      end if;
   end Ghdl_Write_Scalar;

   procedure Ghdl_Read_Scalar (File : Ghdl_File_Index;
                               Ptr : Ghdl_Ptr;
                               Length : Ghdl_Index_Type)
   is
      Res : C_Files;
      R : size_t;
   begin
      Res := Get_File (File);
      Check_File_Mode (File, False);
      if Res = NULL_Stream then
         Error ("write to a non-opened file");
      end if;
      --  FIXME: check mode.
      R := fread (System.Address (Ptr), size_t (Length), 1, Res);
      if R /= 1 then
         Error ("read_scalar failed");
      end if;
   end Ghdl_Read_Scalar;

   function Ghdl_Text_Read_Length (File : Ghdl_File_Index;
                                   Str : Std_String_Ptr)
     return Std_Integer
   is
      Stream : C_Files;
      C : int;
      Len : Ghdl_Index_Type;
   begin
      Stream := Get_File (File);
      Check_File_Mode (File, True);
      Len := Str.Bounds.Dim_1.Length;
      --  Read until EOL (or EOF).
      --  Store as much as possible.
      for I in Ghdl_Index_Type loop
         C := fgetc (Stream);
         if C < 0 then
            Error ("read: end of file reached");
            return Std_Integer (I);
         end if;
         if I < Len then
            Str.Base (I) := Character'Val (C);
         end if;
         --  End of line is '\n' or LF or character # 10.
         if C = 10 then
            return Std_Integer (I + 1);
         end if;
      end loop;
      return 0;
   end Ghdl_Text_Read_Length;

   procedure Ghdl_Untruncated_Text_Read
     (File : Ghdl_File_Index; Str : Std_String_Ptr; Len : Std_Integer_Acc)
   is
      Stream : C_Files;
      Max_Len : int;
   begin
      Stream := Get_File (File);
      Check_File_Mode (File, True);
      Max_Len := int (Str.Bounds.Dim_1.Length);
      if fgets (Str.Base (0)'Address, Max_Len, Stream) = Null_Address then
         Internal_Error ("ghdl_untruncated_text_read: end of file");
      end if;

      --  Compute the length.
      for I in Ghdl_Index_Type loop
         if Str.Base (I) = NUL then
            Len.all := Std_Integer (I);
            exit;
         end if;
      end loop;
   end Ghdl_Untruncated_Text_Read;

   procedure File_Close (File : Ghdl_File_Index; Is_Text : Boolean)
   is
      Stream : C_Files;
   begin
      Stream := Get_File (File);
      Check_File_Mode (File, Is_Text);
      --  LRM 3.4.1  File Operations
      --  If F is not associated with an external file, then FILE_CLOSE has
      --  no effect.
      if Stream = NULL_Stream then
         return;
      end if;
      if fclose (Stream) /= 0 then
         Internal_Error ("file_close: fclose error");
      end if;
      Files_Table.Table (File).Stream := NULL_Stream;
   end File_Close;

   procedure Ghdl_Text_File_Close (File : Ghdl_File_Index) is
   begin
      File_Close (File, True);
   end Ghdl_Text_File_Close;

   procedure Ghdl_File_Close (File : Ghdl_File_Index) is
   begin
      File_Close (File, False);
   end Ghdl_File_Close;

   procedure Ghdl_File_Flush (File : Ghdl_File_Index)
   is
      Stream : C_Files;
   begin
      Stream := Get_File (File);
      if Stream = NULL_Stream then
         return;
      end if;
      fflush (Stream);
   end Ghdl_File_Flush;
end Grt.Files;