Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!mit-eddie!godot!harvard!seismo!brl-tgr!tgr!mrose%udel-eecis2.delaware@UDEL-LOUIE.ARPA From: Marshall RoseNewsgroups: net.mail.headers Subject: Re: RFC 934 - Message Encapsulation Message-ID: <8155@brl-tgr.ARPA> Date: Fri, 8-Feb-85 23:31:32 EST Article-I.D.: brl-tgr.8155 Posted: Fri Feb 8 23:31:32 1985 Date-Received: Tue, 12-Feb-85 05:12:28 EST Sender: news@brl-tgr.ARPA Organization: Ballistic Research Lab Lines: 32 Unfortunately, requiring more dashes just makes the problem harder and introduces additional ambiguity. Let me explain. A primary motivation for writing that RFC was that I was getting tired of constantly modifying the bursting agent in MH. First, I tried looking for 5 dashes at the beginning of a line. Sure enough, some digests let that through. Then I upped it to 30. Sure enough, some digests let that through. Then I got clever and introduced special heuristics based on the number of blank lines both preceeding and following the line that started with the dashes. Still not good enough. I then decided to look at least TWO LINES ahead and see if I could find what looked like a header. Still no good, one day someone just happened to have a couple of blank lines, a line of dashes, a couple of blank lines, all followed by a line that looked like a header. Brute force and extremely clever coding just can't compete. So, I decided that we need to bit (well, byte) stuff. This is the ONLY way to unambiguously separate messages in a digest (or a forwarding of messages, in general). So, if you're going to change all that software in net to be considerate and generate digests etc., that other software can burst, then you might as well make the change as simple as possible. Hence, the choice of a single dash for the EB. The RFC contains very simple algorithms to byte-stuff on encapsulation and to burst on decapsulation. The latter algorithm, in fact, needs only one character look-ahead. The point of all this is that I want to get painless bursting with the absolute LEAST amount of effort on the part of the mail hackers in the net. I really don't think it's too difficult to look at the beginning of each line and output a "- " if it starts with a "-". /mtr