Converting from BASE 64 to Decimal Base 10

Question

I have an requirement to convert a value from base 64 to decimal base 10
for ex if i give b the resultant output should be 27
as per the website -- http://convertxy.com/index.php/numberbases/
I tried using the UTL_ENCODE.BASE64_ENCODE with UTL_RAW.CAST_TO_RAW
select utl_raw.cast_to_varchar2(utl_encode.base64_encode(utl_raw.cast_to_raw('b'))) from dual
but i am not getting the desired result
Kindly guide me in this issue
With Warm Regards
SSR

Answer 1

The base64 encoding for 27 is not b
SELECT UTL_RAW.cast_to_varchar2 (
          UTL_ENCODE.base64_encode (
             UTL_RAW.cast_to_raw (
                '27')))
          base64
  FROM DUAL
BASE64
"Mjc="27 ist the position of b in
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
which you need in the first step to convert base64 to decimal.
select
instr(
  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
,'b'
) -1 d
from dual
d
27
vice versa
select
substr(
  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
  ,27 + 1
  ,1
) d
from dual
D
"b"You dont get a result with your approach because b is not a valid base64-encoding.
Otherwise thsi should give a result
SELECT UTL_RAW.cast_to_varchar2 (
          UTL_ENCODE.base64_decode (
             UTL_RAW.cast_to_raw (
                'b')))
          base64
  FROM DUAL
BASE64
but it doesnt, it does in the case below
SELECT UTL_RAW.cast_to_varchar2 (
          UTL_ENCODE.base64_decode (
             UTL_RAW.cast_to_raw (
                'Mjc=')))
          base64
  FROM DUAL
BASE64
"27"Edited by: chris227 on 12.03.2013 07:36
Edited by: chris227 on 12.03.2013 07:41
Edited by: chris227 on 12.03.2013 07:46
Edited by: chris227 on 12.03.2013 08:20