Oracle pl/sql function urlencode, urldecode

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create or replace function urlencode
----------------------------------------------------------------------
(p_str in varchar2) return varchar2 is

/* Declare */
l_tmp varchar2(6000);
l_hex varchar2(16) default ‘0123456789ABCDEF’;
l_num number;
l_bad varchar2(100) default ‘ >%}\~];?@&<#{|^[`/:=$+''"';
l_char char(1);

begin
if p_str is null
then
return null;
end if;
for i in 1 .. length(p_str) loop
l_char := substr(p_str, i, 1);
if instr(l_bad, l_char) > 0
then
l_num := ascii(l_char);
l_tmp := l_tmp || ‘%’ ||
substr(l_hex, mod(trunc (l_num / 16), 16) + 1, 1) ||
substr(l_hex, mod(l_num, 16) + 1, 1);
else
l_tmp := l_tmp || l_char;
end if;
end loop;
return l_tmp;
end urlencode;
/

----------------------------------------------------------------------
create or replace function urldecode
----------------------------------------------------------------------
(p_str in varchar2) return varchar2 is

/* Declare */
l_hex varchar2(16) := ‘0123456789ABCDEF’;
l_idx number := 0;
l_ret long := p_str;

begin
if p_str is null then
return p_str;
end if;
loop
l_idx := instr(l_ret, ‘%’, l_idx + 1);
exit when l_idx = 0;
l_ret := substr(l_ret, 1, l_idx - 1) ||
chr((instr(l_hex, substr(l_ret, l_idx + 1, 1)) - 1) * 16 +
instr(l_hex, substr(l_ret, l_idx + 2, 1)) - 1) ||
substr(l_ret, l_idx + 3);
end loop;
return l_ret;
end urldecode;
/

Test:
SQL> select urlencode(’&+=’) from dual;
URLENCODE(’&+=’)
——————————————————————————–
%26%2B%3D
SQL> select urldecode(’%26%2B%3D’) from dual;
URLDECODE(’%26%2B%3D’)
——————————————————————————–