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Bob Wyman wrote:
> Just as XML works well in both "schema-based" and
>"schema-free" environments, it is critical that any alternative binary
>encoding do the same. But, it is also useful to recognize that when
>you're working with XML, you are never really in a "schema-free"
>environment... Even if you don't have an application-specific schema,
>you've still got the schema for XML itself -- the InfoSet .
> If you have an application-specific schema, you can do all
>sorts of optimizations in the binary encodings and get really great
>compression as well as parsing efficiencies based on your knowledge of
>the schema. When working with the Infoset alone, you can't get quite
>as much benefit from a binary encoding, but for many (not all)
>applications the benefit will still be great enough to justify the
>effort. For instance, you won't get as much compression with an
>Infoset based encoding, but you'll still usually benefit from having
>counted length strings and other benefits that make parsing more
>efficient. (We exploit these efficiencies at PubSub.com, for more
>info see  below.)
I'm well aware of Infoset-based encodings, since my own XBIS project
(http://www.xbis.org) is one of them. I was curious how ASN.1 deals with
data at the Infoset level, rather than schema-specific versions.
I didn't see anything about this in a quick look through the references.
Sun claims both schema and Infoset support for "Fast Web Services" in
the "Binary Interchange of XML Infosets" report
but doesn't mention the Infoset at all in the paper describing this
find their specific results of dubious use, but don't doubt that when a
specific schema is known it's possible to get better results (in terms
of both data size and processing speed) for an encoding that matches the
schema rather than a general Infoset encoding.
Dennis M. Sosnoski
Enterprise Java, XML, and Web Services
Training and Consulting
Redmond, WA 425.885.7197