Re: binary base64 definition

[Ian Graham <igraham@ic-unix.ic.utoronto.ca>]

The DOM supports access to notation nodes, but can enforce no statement
aobut the proper encoding of a referenced external entity (which makes
sense, as it is external to the document).

Base64 encoding of content inside a document would require custom code for
doing the encoding/decoding, and some attribute-based mechanism for
labeling the 'type' content of the node containing the data. That is
certainly possible, but as far as I can see is outside the scope of the
DOM. 

Ian


On Fri, 5 Jan 2001, Dan Vint wrote:

> You can't use elements this way, but an alternative would be to create a 
> NOTATION type and then an external entity of this type - you would copy all
> the contents of whatever should be base 64 into this external file, it
> would be part of the XML document but it would be outside. Not sure if
> DOM has been setup to understand NOTATIONS, but in an SGML world you would
> be able to associcate a "processor" with that notation and have it called 
> whenever you needed to read or write that format. 
> 
> Your DTD might look like the following:
> 
> <!DOCTYPE .... [
> 
> <!NOTATION base64 SYSTEM "binary base64">
> <!ENTITY extfile1 SYSTEM "extfile.b64" NOTATION "base64" >
> 
> ]>
> ....
> &extfile1;
> ...
> 
> The syntax is probably not exact but you can look up the details.
> 
> ..dan
> 
> > 
> > In the DTD, can I specify a type of "binary base64" for an element so that
> > when I write to the XML file using DOM, DOM will automatically encode the
> > binary data for me without parsing for control characters? If so, I assume
> > it will do the reverse when I read that element.
> > 
> > Can anyone validate my assumption about the DTD data type? Has anyone seen
> > an example DTD definition with this in it?
> > 
> > Thanks much.
> > Jerry
> > 
> 
>