[Oracle] to_dec, to_hex, to_bin, to_oct (10진수,16진수,2진수,8진수)

-- 진수 변환을 위한 핵심 함수 
create or replace function to_base(p_dec in number, p_base in number)
    return varchar2
    
    is 
      l_str varchar2(255) default NULL;
      l_num number default p_dec;
      l_hex varchar2(16) default '0123456789ABCDEF';
      
    begin
    
      if ( trunc(p_dec) <> p_dec OR p_dec < 0 ) then
        raise PROGRAM_ERROR;
      end if;
      
      loop
        l_str := substr(l_hex, mod(l_num, p_base)+1, 1) || l_str;
        l_num := trunc( l_num/p_base);
        exit when (l_num = 0);
      end loop;

      return l_str;
    end to_base;
    /
    

-- 10진수로 변환
create or replace function to_dec(p_str in varchar2, p_from_base in number default 16) return number
    is 
      l_num number default 0;
      l_hex varchar2(16) default '0123456789ABCDEF';
      
    begin
    
      for i in 1 .. length(p_str) loop
        l_num := l_num*p_from_base + instr(l_hex, upper(substr(p_str,i,1))) -1;
      end loop;
    return l_num;

  end to_dec;
  /

  
-- 16진수로 변환
create or replace function to_hex(p_dec in number) return varchar2
    is 
    begin
      return to_base(p_dec, 16);
    end to_hex;
    /

    
--2진수로 변환
create or replace function  to_bin(p_dec in number) return varchar2
    is 
    begin
      return to_base(p_dec,2);
    end to_bin;
  /

  
-- 8진수로 변환
create or replace function to_oct(p_dec in number) return varchar2
    is
    begin
      return to_base(p_dec, 8);
    end to_oct;
    /