In its last incarnation the Readmail program could read, but could not
delete messages in Soup (or Yarn) binary format.

In earlier mail, I suggested a workaround for this: Tell readmail
the messages are in non-binary format, and specify the start of
each message header by the first alphanumeric strings you could
reliably expect to be in the first line of the header.

I was wrong abou this solution. I will work partially in that,
as long as you use only readmail, the solution will indeed allow
you to delete individual messages and the software will track
the messages accordingly.

However, this solution will not always, or even usually preserve
the integrety of Soup (or Yarn) headers. The latter signals the
start of each message header with the size of the whole message,
in bytes, expressed as a number in modular 8 arithmetic (instead of
the usual mod 10). Of course, one of the bytes that is part of this
number may well correspond to the ascii value that is the code for
a line feed and/or a carrage return.  If that happens, any scanner like
readmail's, that is looking at ascii ``lines'' one at a time, will interpret
part of the number that specifies the size of the message, as the end of
a line.  It will throw way any part of the number before this ``end-of-
line'' and get everything wrong during a message delete.

I expect the way most software parses Soup headers is via a linked list
approach:  Read the first 4 bytes of the file to find the size of the
first message, goto to that offset, and read the next 4 bytes for the
size of the next message, etc. With that approach, even a single byte
missing or abnormally present will throw off the parsing of all the
messages. Thus, SOUP mail programs will be unable to read a mail
file after readmail deletes some messages from it.

If I am correct on this, what is the advantage of such a demanding
header format? Why is it not better to just pick a distinctive string,
like the Unix ``From '' to start each header?

To unsubscribe from SURVPC send a message to [EMAIL PROTECTED] with 
unsubscribe SURVPC in the body of the message.
Also, trim this footer from any quoted replies.

Reply via email to