XP Mail Archive: XP> Re: xhtml-print: RFC3391 interpretation

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

From: don@lexmark.com
Date: Thu Apr 08 2004 - 12:06:53 EDT

  • Next message: PARAB,DEEPALI (HP-Boise,ex1): "RE: XP> xhtml-print: RFC3391 interpretation question: how much vi sual sep aration ends a chunk?"

    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
    buffers.

    "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
       CRLF.

         - 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:

    </body>
    </html>
    CHK 0 0 LAST

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

    </body>
    </html>

    CHK 0 0 LAST

    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
    the
    example 2.

    Jim

    [1] http://www.ietf.org/rfc/rfc3391.txt
     [2] http://www.w3.org/TR/xhtml-print/



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