Arduino libary for Base32 (rfc4648) decoding.

Traditional C interface

base32decode : decode a \0 terminated base32 encoded string.

int base32decode(
   const char * encoded, 
   unsigned char * decodedBytes, 
   size_t maxbuf
);

inputs:

encoded        \0 terminated char buffer with encoded string
decodedBytes   outputbuffer (or NULL)
maxbuff        size of the output buffer

outputs:

returns the decoded byte array in decodedBytes and the length. Or if decodedBytes==NULL, will just return the length needed; regardless of the value of maxbuff.

If the size of maxbuff allows it - a terminating \0 is added (but not including in the length returned) - as very often the decoded data itself is actually again a string.

C++/INO/Arduino# tring interface

base32decodeToString - decode a String into a decoded String

int base32decodeToString(String encoded, String &decoded);

inputs:

encoded   String with the encoded base32 value
&decoded  returned string (if any)

outputs:

Will return the length of the decoded string or a negative value on error.

Example

Typical use:

String in = "IFZGI5LJNZXSAUTVNRSXU===";
String out;

int r = base32decodeToString(in, out);
if (r < 0) {
  Serial.println("Could not decode the string");
  return;
};

Serial.print("Decoded: ");
Serial.println(out);