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Re: xhtml-print: RFC3391 interpretation question: how much visual separation ends a chunk?

From: <don@lexmark.com>
Date: Thu, 8 Apr 2004 12:06:53 -0400
To: "BIGELOW,JIM (HP-Boise,ex1)" <jim.bigelow@hp.com>
Cc: Elliott Bradshaw <Elliott.Bradshaw@Zoran.com>, www-html-editor@w3.org, xp@pwg.org
Message-ID: <OF8CF9AB0A.51BE7A5D-ON85256E70.0057F8E0-85256E70.00587D99@lexmark.com>

Jim, et al:

Well.... if I were coding it, once I reached the end of the byte count for
that CHK, I would ignore any and all white space until I got to something
of meaning such as the next CHK.  But that's just me and when I coded in
assembler, I always included code to check to make sure I never overran my

"Be perfect in what you send, liberal in what you'll accept."

 Don Wright                 don@lexmark.com

 Chair,  IEEE SA Standards Board
 Member, IEEE-ISTO Board of Directors
 f.wright@ieee.org / f.wright@computer.org

 Director, Alliances & Standards
 Lexmark International
 740 New Circle Rd
 Lexington, Ky 40550
 859-825-4808 (phone) 603-963-8352 (fax)

|         |           "BIGELOW,JIM     |
|         |           (HP-Boise,ex1)"  |
|         |           <jim.bigelow@hp.c|
|         |           om>              |
|         |                            |
|         |           04/08/2004 11:51 |
|         |           AM               |
|         |                            |
  |                                                                                                                    |
  |       To:       www-html-editor@w3.org, Elliott Bradshaw <Elliott.Bradshaw@Zoran.com>, don@lexmark.com             |
  |       cc:       xp@pwg.org                                                                                         |
  |       Subject:  xhtml-print: RFC3391 interpretation question: how much visual sep       aration ends a chunk?      |

I'm looking for opinions on the interpretation of RFC3391 [1] since it is
normatively referenced by XHTML-Print [2].

RFC 3391 says,
   An Application/Vnd.pwg-multiplexed entity contains a sequence of
   chunks.  Each chunk consists of a chunk header, a chunk payload and a

     - The chunk header consists of a "CHK" keyword followed by the
       message number, the chunk payload length, whether the chunk is
       the last chunk of a message and, finally, a CRLF.  The length
       field removes the need for boundary strings that Multipart uses.
       (See section 3.1 for the syntax of a chunk header).

     - The chunk payload is a sequence of octets that is either a
       complete message or a part of a message.

     - The CRLF provides visual separation from the following chunk.

There are several situations where a single CRLF does not provide visual
separation since the CRLF added to the document simply terminates a line
rather than adding a empty line.  For example in an XHTML-Print document
didn't contain a terminating CRLF and adding a single CRLF  would give the
result shown below in example 1:


Rather than the following, example 2, I expected from reading the spec:



This could also occur when interleaving images and the root document.

I think this issue will have a large impact on interoperability between
printers and producers of multiplexed documents.  So I'd like to get  other
people's interpretations of this matter.

If I don't hear from anyone, I'll assume agreement that the multiplexed
document should contain visual separation at the end of the chunk, as in
example 2.


[1] http://www.ietf.org/rfc/rfc3391.txt
 [2] http://www.w3.org/TR/xhtml-print/
Received on Thursday, 8 April 2004 12:07:44 UTC

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