From 059ccd4723439d66973926763cb3617a88b1c6d5 Mon Sep 17 00:00:00 2001 From: Peter Saint-Andre Date: Wed, 26 Sep 2007 22:51:52 +0000 Subject: [PATCH] 1.3 git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@1242 4b5297f7-1745-476d-ba37-a9c6900126ab --- xep-0138.xml | 44 ++++++++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 20 deletions(-) diff --git a/xep-0138.xml b/xep-0138.xml index 01b4c295..82d83b2e 100644 --- a/xep-0138.xml +++ b/xep-0138.xml @@ -30,53 +30,59 @@ &hildjj; &stpeter; + + 1.3 + 2007-09-26 + psa +

Moved specification of LZW algorithm to XEP-0229.

 + 1.2 2007-08-22 psa - Clarified when compression shall be considered to start; per XEP-0170, specified that compression should be negotiated after SASL. +

Clarified when compression shall be considered to start; per XEP-0170, specified that compression should be negotiated after SASL.

 1.1 2005-12-14 psa - More completely specified error handling; mentioned LZW (DCLZ) method. +

More completely specified error handling; mentioned LZW (DCLZ) method.

 1.0 2005-06-16 psa - Per a vote of the Jabber Council, advanced status to Draft. +

Per a vote of the Jabber Council, advanced status to Draft.

 0.5 2005-05-18 psa - Modifications to address Council feedback: used RFC 3920 terminology; specified error conditions; specified ZLIB as mandatory to implement. +

Modifications to address Council feedback: used RFC 3920 terminology; specified error conditions; specified ZLIB as mandatory to implement.

 0.4 2005-05-11 psa - Corrected several errors in the schemas. +

Corrected several errors in the schemas.

 0.3 2005-03-28 psa - Specified compression methods registry. +

Specified compression methods registry.

 0.2 2004-09-28 psa - Fixed TLS text per list discussion. +

Fixed TLS text per list discussion.

 0.1 2004-07-16 jjh/psa - Initial version. +

Initial version.

 @@ -190,16 +196,19 @@ -

A compliant implementation MUST implement the ZLIB compression method as specified in &rfc1950;. All other methods are OPTIONAL; such methods may be defined in future specifications or by registration as described in the Compression Methods Registry section of this document.

+

Support for the ZLIB compression method as specified in &rfc1950; is REQUIRED.

+

All other methods are OPTIONAL; such methods may be defined in future specifications or by registration as described in the Compression Methods Registry section of this document.

+ + + +

Implementations MAY support the following methods in addition to ZLIB:

+
    +
  • &xep0229;
    • +
- -

When using ZLIB for compression, the sending application SHOULD complete a partial flush of ZLIB when its current send is complete. Note that this statement is deliberately somewhat vague: the sending application may end up performing this partial flush after sending every XML stanza, but on the other hand may perform the partial flush only after sending a group of stanzas that have been queued up for delivery. When to flush the state of the compression application is up to the sending application.

- - -

The "LZW" compression algorithm was originally developed by Abraham Lempel and Jacob Ziv, subsequently improved by Terry Welch See "A Technique for High-Performance Data Compression", Computer (June 1984), pp. 8-19., and patented by Sperry Corporation (later Unisys Corporation) as U.S. Patent Number 4,464,650 See <http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=4,464,650>.. This patent expired on June 20, 2003 See <http://www.unisys.com/about__unisys/lzw>. and therefore implementations are no longer patent-encumbered. If this algorithm is supported, implementations SHOULD follow the specification provided by Ecma International in &ecma151; under the name "DCLZ".

- +

When using ZLIB for compression, the sending application SHOULD complete a partial flush of ZLIB when its current send is complete. Note that this statement is deliberately somewhat vague: the sending application may end up performing this partial flush after sending every XML stanza, but on the other hand may perform the partial flush only after sending a group of stanzas that have been queued up for delivery. When to flush the state of the compression application is up to the sending application.

 @@ -232,11 +241,6 @@ - lzw - the LZW (DCLZ) compression method - ECMA-151 - zlib the ZLIB compression method