Problem - Kevin Tafuro

*p = 0;
return output;
}
}
}
The public interface to the above code is the following:
unsigned char *spc base64_encode(unsigned char *input, size_t len, int wrap);
The result is a NULL-terminated string allocated internally via malloc( ). Some protocols
may expect you to “wrap” base64-encoded data so that, when printed, it takes
up less than 80 columns. If such behavior is necessary, you can pass in a non-zero
value for the final parameter, which will cause this code to insert newlines once every
76 characters. In that case, the string will always end with a newline (followed by the
expected NULL-terminator).
If the call to malloc( ) fails because there is no memory, this function returns 0.
See Also
Recipe 4.6
4.6 Performing Base64 Decoding
Problem
You have a base64-encoded string that you’d like to decode.
Solution
Use the inverse of the algorithm for encoding, presented in Recipe 4.5. This is most
easily done via table lookup, mapping each character in the input to six bits of output.
Discussion
Following is our code for decoding a base64-encoded string. We look at each byte
separately, mapping it to its associated 6-bit value. If the byte is NULL, we know that
we’ve reached the end of the string. If it represents a character not in the base64 set,
we ignore it unless the strict argument is non-zero, in which case we return an
error.
The RFC that specifies this encoding says you should silently ignore
any unnecessary characters in the input stream. If you don’t have to do
so, we recommend you don’t, as this constitutes a covert channel in
any protocol using this encoding.
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