Re: MIME boundary question

[John Gardiner Myers <jgm+@xxxxxxx>]

"John W. Noerenberg" <jwn2@qualcomm.com> writes:
> John, the only implementation that I know about that can't handle
> boundaries containing substrings of other boundaries is the one from
> Frontier.  What others can't handle this?

The ones I know of are metamail and mpack.

> The bnf in 1341 doesn't prohibit a boundary token from being a superset of
> a second boundary contained by the first one.  It requires it to be
> different, but a superset satisfies that requirement.

The BNF in 1341 for a body-part prohibits the outer multipart's
delimiter from occuring within the body-part.  This effectively
prohibits enclosed multiparts from having boundaries which have a
prefix of the enclosing mulipart's boundary.

This rule in the BNF is necessary to keep the multipart grammar from
being ambiguous.  Otherwise, when you see something that looks like a
delimiter, you don't know whether it should parse as a delimiter or as
part of the enclosed body-part.

-- 
_.John G. Myers		Internet: jgm+@CMU.EDU
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