library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_arith.all;
Use STD.TEXTIO.ALL;   -- for reading and writing a file

-- IMPORTANT: the input file for decimal reading: there must be a space between 
-- to number and at the end of line
-- for binary input: there must be space between each number and each number must be exactly
-- 16 bit

 -- my own file , contains some function to read and write data
-- and convert sdt_logic to integer. check read_write_package
use work.read_write_library.all;

-- you have to define input output file where you define entity.
-- you cannot send file name as paramater, simulation gives
-- error message. In this example I defined an input and an output file.
-- It reads data from a file put them in array when start=1. 
-- when start=0, it counts the clock cycle and at each clock cycle
-- it writes counted clock cycle and an array element to clk_data.txt
-- output file. It writes them as integer.  when all read data is written 
-- into output files, it stops.

entity read_write is
     generic ( 
           input_file:       string  := "input.txt";
           decimal_file: string:="decimal_input.txt";
           decimal_output: string:="decimal_out.txt";
           output_bin_to_integer: string:="bin_to_integer.txt"
          );
   
end entity;

architecture behav of read_write is
-- at here file are opened to be read
 file input: TEXT open read_mode is input_file;
 file output1: TEXT open write_mode is output_bin_to_integer;
 file DEC_input: TEXT open read_mode is decimal_file;
 file DEC_output: TEXT open write_mode is decimal_output;

signal clk, start:std_logic;

component clock is
    generic (half_period:Time:=20 ns);
    port(clk_out:out std_logic);
end component;


begin

   C:clock port map(clk);

-- SD 04/23/09: The clk part is not needed here

    start_proc: process  is
    begin
       start <= '1';
       wait for 20 ns;
       start <= '0';
       wait;
    end process;


-- the process below reads in integers in binary form and writes out
-- data produced in decimal form

read_binary_and_write_decimal: process  is

variable check:bit_vector(15 downto 0):=X"0000";
-- SD 04/23/09 variable mult1,mult2,result:integer;
variable add_num1, add_num2, result:integer;
variable ch : character;
variable buf: line;-- this part need to be defined to able to write a file
begin

if start = '1' then
    while not endfile(input) loop
      readline(input,buf);

      read_1(buf,check); -- reads binary data from the buffer "buf" that
                         -- contains a "line" of data
      add_num1:=convert_to_integer(check);
      read(buf,ch); -- skip space
      read_1(buf,check); -- reads binary data
      add_num2:=convert_to_integer(check);
      result:=add_num1+add_num2;
        write(buf,integer'image(add_num1)); -- take add_num1 and write each digit as character
        write(buf,string'(" + "));
        write(buf,integer'image(add_num2));
        write(buf,string'(" = "));
	write(buf,integer'image(result)); -- take result and write each digit as character
        report("write file");
        writeline(output1,buf);
      
   end loop;
   report(" read is done");
   file_close(input);
   file_close(output);
   wait;

end if; 
 
end process;


-- this process reads in integers in decimal form and writes out
-- data produced also in decimal form
read_and_write_decimal :process  is
       variable inp_buf,out_buf: line;
       variable c: character;
       variable add_num1,add_num2,result:integer;


-- this procedure reads the decimal number until read character is space ot any other character.
-- L is the line which is read from file
-- n is the integer value 


  begin

  if start = '1' then
    while not endfile(DEC_input) loop
 
       add_num1:=0;
       add_num2:=0;	  
        readline(DEC_input,inp_buf); -- at here we are reading 2 number. There is only
	read_integer(inp_buf,add_num1); -- one space between 2 number otherwise it will
	read_integer(inp_buf,add_num2); -- not read second one
       result:=add_num1+add_num2;
        write(out_buf,integer'image(add_num1));
        write(out_buf,string'(" + "));
        write(out_buf,integer'image(add_num2));
        write(out_buf,string'(" = "));
	write(out_buf,integer'image(result)); -- take result and write each digit as character
        writeline(DEC_output,out_buf);
    end loop;
    report("secon file is done");
    file_close(DEC_output); -- standart textio library functions
    file_close(DEC_input);
    wait;
 end if;
end process;

end architecture;