[xsl] Dividing documents based on size of contents

[Chris von See <chris@xxxxxxxxxxxxx>]

Hi all -

I have what I think is a fairly simple problem, but I'm having trouble  
with the implementation in XSLT.  Any help you could give would be  
greatly appreciated.

I have a document which is subdivided into multiple sections, with  
each section, in turn, divided into pages as shown below:

<document>
	<documentDivision>
		... arbitrary content ...
		<pagebreak />
		... arbitrary content ...
		<pagebreak />
	</documentDivision>

	... arbitrary number of <documentDivision> elements ...

</document>

Each <documentDivision> section of the document can have an arbitrary  
number of <pagebreak> elements, and an arbitrary amount of content  
between <pagebreak>s.

I'd like to be able to break the input <document> into multiple  
<document>s, each of which has the minimum number of  
<documentDivision> sections that give it a <pagebreak> count ~100  
pages.  I'd like to break the input at <documentDivision> boundaries,  
but I don't need the output documents to be equally sized or to be  
exactly 100 pages long - just as close to that size as I can  
reasonably get while maintaining the <documentDivision> boundaries.

So for example if I have an input document that looks like this:

<document>
	<documentDivision>
		... content containing 50 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 50 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 127 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 5 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 23 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 78 <pagebreak /> elements ...
	</documentDivision>
</document>

the output documents should look like this, with each output document  
being "close" to 100 pages in length:

<!-- This doc has enough <documentDivision> elements to give exactly  
100 pages. -->
<document>
	<documentDivision>
		... content containing 50 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 50 <pagebreak /> elements ...
	</documentDivision>
</document>

<!-- This doc has a single <documentDivision> element with 127 pages -  
close enough! -->
<document>
	<documentDivision>
		... content containing 127 <pagebreak /> elements ...
	</documentDivision>
</document>

<!-- This doc has a three <documentDivision> elements of 5, 23 and 78  
pages each - close enough! -->
<document>
	<documentDivision>
		... content containing 5 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 23 <pagebreak /> elements ...
	</documentDivision>
	<documentDivision>
		... content containing 78 <pagebreak /> elements ...
	</documentDivision>
</document>

I've been able to figure out how to get the number of <pagebreak>s per  
<documentDivision> and how to calculate the number of <pagebreak>s in  
any given group of <documentDivision> sections, but what I'm not sure  
of is how to maintain information about the point at which I last  
created a new output document so that I can determine what group of  
<documentDivision> elements has a page count around 100 and should  
therefore be used to create a new output document.  It seems that the  
best way to carry this context would be via params to xsl;apply- 
templates, but I'm not clear on how to set up the XSLT code so that  
the state gets maintained as I iterate through <documentDivision>  
elements.  It also seems like there should be some XPath expression  
that I can use with xsl:for-each-group, but I can't quite figure out  
how to write that such that each group has only the minimum number of  
<documentDivision> elements needed to accumulate 100-ish pages.

Do you have any guidance on ways to do this?  I think I'm just having  
a mental block, and a swift kick in the right direction should do the  
trick.


Thanks
Chris