rem -----------------------------------------------------------------------
rem Filename:   dbms_numsystem.sql
rem Purpose:    Package with functions to convert numbers between the 
rem             Decimal, Binary, Octal and Hexidecimal numbering systems.
rem Usage:      See sampels at the bottom of this file
rem Author:     Frank Naude, 17 February 2003
rem -----------------------------------------------------------------------

set serveroutput on

CREATE OR REPLACE PACKAGE dbms_numsystem AS
   function bin2dec (binval in char  ) RETURN number;
   function dec2bin (N      in number) RETURN varchar2; 
   function oct2dec (octval in char  ) RETURN number;
   function dec2oct (N      in number) RETURN varchar2; 
   function hex2dec (hexval in char  ) RETURN number;
   function dec2hex (N      in number) RETURN varchar2; 
END dbms_numsystem;
/
show errors

CREATE OR REPLACE PACKAGE BODY dbms_numsystem AS

FUNCTION bin2dec (binval in char) RETURN number IS
  i                 number;
  digits            number;
  result            number := 0;
  current_digit     char(1);
  current_digit_dec number;
BEGIN
  digits := length(binval);
  for i in 1..digits loop
     current_digit := SUBSTR(binval, i, 1);
     current_digit_dec := to_number(current_digit);
     result := (result * 2) + current_digit_dec;
  end loop;
  return result;
END bin2dec;

FUNCTION dec2bin (N in number) RETURN varchar2 IS
  binval varchar2(64);
  N2     number := N;
BEGIN
  while ( N2 > 0 ) loop
     binval := mod(N2, 2) || binval;
     N2 := trunc( N2 / 2 );
  end loop;
  return binval;
END dec2bin;

FUNCTION oct2dec (octval in char) RETURN number IS
  i                 number;
  digits            number;
  result            number := 0;
  current_digit     char(1);
  current_digit_dec number;
BEGIN
  digits := length(octval);
  for i in 1..digits loop
     current_digit := SUBSTR(octval, i, 1);
     current_digit_dec := to_number(current_digit);
     result := (result * 8) + current_digit_dec;
  end loop;
  return result;
END oct2dec;

FUNCTION dec2oct (N in number) RETURN varchar2 IS
  octval varchar2(64);
  N2     number := N;
BEGIN
  while ( N2 > 0 ) loop
     octval := mod(N2, 8) || octval;
     N2 := trunc( N2 / 8 );
  end loop;
  return octval;
END dec2oct;

FUNCTION hex2dec (hexval in char) RETURN number IS
  i                 number;
  digits            number;
  result            number := 0;
  current_digit     char(1);
  current_digit_dec number;
BEGIN
  digits := length(hexval);
  for i in 1..digits loop
     current_digit := SUBSTR(hexval, i, 1);
     if current_digit in ('A','B','C','D','E','F') then
        current_digit_dec := ascii(current_digit) - ascii('A') + 10;
     else
        current_digit_dec := to_number(current_digit);
     end if;
     result := (result * 16) + current_digit_dec;
  end loop;
  return result;
END hex2dec;

FUNCTION dec2hex (N in number) RETURN varchar2 IS
  hexval varchar2(64);
  N2     number := N;
  digit  number;
  hexdigit  char;
BEGIN
  while ( N2 > 0 ) loop
     digit := mod(N2, 16);
     if digit > 9 then 
        hexdigit := chr(ascii('A') + digit - 10);
     else
        hexdigit := to_char(digit);
     end if;
     hexval := hexdigit || hexval;
     N2 := trunc( N2 / 16 );
  end loop;
  return hexval;
END dec2hex;

END dbms_numsystem;
/
show errors

-- Examples:
select dbms_numsystem.dec2bin(22)      from dual;
select dbms_numsystem.bin2dec('10110') from dual;
select dbms_numsystem.dec2oct(44978)   from dual;
select dbms_numsystem.oct2dec(127662)  from dual;
select dbms_numsystem.dec2hex(44978)   from dual;
select dbms_numsystem.hex2dec('AFB2')  from dual;