library IEEE;
use IEEE.std_logic_1164.all;
use STD.textio.all;
package read_write_library is
  procedure write_1(variable f:out text;v:in bit_vector);
  function convert_to_integer ( bv : in bit_vector ) return integer;
  procedure read_1(buf :inout line ;v:out bit_vector) ;
  procedure read_integer(L : inout line;  n : out integer);
end package read_write_library;


--reads binary data from a file (f: is file name)
package body read_write_library is

procedure read_integer(L : inout line;  n : out integer) is
variable result : integer := 0;
variable ll:integer:=0;
variable ch: character;
variable negative:integer:=1;-- if input is negative, during reading this value will be negative
begin
     while(ll=0) loop  -- until not decimal number
          read(L, ch);
          if(ch='-') then -- check it is sign character
              negative:=-1;
          else
	      if('0' <= ch and ch <= '9') then -- convert ascii to integer
             result := result*10 + character'pos(ch) - character'pos('0');
               else
	         ll:=1; -- not valid character may be it is space
	     end if;
         end if;   
     end loop;
       n := negative*result; -- if negative, convert positive number to negative.
end read_integer;



function convert_to_integer ( bv : in bit_vector ) return integer is
-- function assumes that bv's range is defined in "n-1 downto 0" style
    variable temp : bit_vector(bv'range);
    variable result : integer := 0;

  begin
    if bv(bv'left) = '1' then	  -- negative number
      temp := not bv;
    else
      temp := bv;
    end if;
    for index in bv'range loop
      result := result * 2 + bit'pos( temp(index) );
      -- bit'pos( temp(index) ) is the position (an integer starting from 0:
      -- left most position is 0) of the bit value "temp(index)"
      -- in enumerated type "bit". So bit value '0''s position is the integer 0
      -- and bit value '1''s position is the integer 1.
      -- this conversion is needed from bit -> integer to perform the above
      -- arithmetic operations.
    end loop;
    if bv(bv'left) = '1' then
      result := (-result) - 1;
    end if;
    return result;
  end function convert_to_integer;

  procedure read_1(buf :inout line ;v:out bit_vector) is
    variable c: character;

  begin
    for i in v'range loop -- do character to bit conversion
         read(buf,c);
         case c is
            when '1' => v(i):='1';
            when '0' => v(i):='0';
            when others => v(i) :='0';

         end case;
    end loop;
  end procedure read_1;

--writes binary data to a file
  procedure write_1(variable f:out text;v:in bit_vector) is
    variable buf: line;
    variable c: character;

  begin
    for i in v'range loop
         case v(i) is
            when '1' => write(buf,character'('1'));
            when '0' => write(buf,character'('0'));
            when others => write(buf,character'('0'));
         end case;
    end loop;
    writeline(f,buf);
  
  end procedure write_1;


end package body read_write_library ;