Re: base64 behavior is not MIME compliant

[Ken Raeburn <raeburn@raeburn.org>]

On Jul 5, 2005, at 18:10, Nic Ferrier wrote:
> Why can't you just pre-parse the data parsed to the base64 decoder? I
> believe that's the correct behaviour. A base64 decoder should decode
> base64, not "base64 but also it does this extra trick if you wave your
> hand in the air"

Except "this extra trick" is specifically outlined as an option in the 
base64 spec (RFC 3548), and MIME invokes that option.  So proper "MIME 
base64 decoding" would require this extra step of throwing away 
characters that are not part of a base64 encoding, and then making a 
second pass with the strict base64 decoder.  In fact, as I read RFC 
3548 section 2.3, the CR/LF line break sequences in MIME messages are 
not part of the base64 alphabet, and therefore 
fns.c:IS_BASE64_IGNORABLE already implements a limited form of what 
Marc is asking for.

Ken