OutOfMemory when using str:tokenize or str:split

There appears to be a severe resource leak issue when using the
functions str:tokenize or str:split as included in the latest version of
Xalan (2.7.0, and also 2.6.1).  Even for relatively small XML files,
when repeatedly using these functions, we are encountering OutOfMemory
exceptions even with large (2GB) maximum heap sizes.  This may be
related to a previous mailing list posting, which asks whether this is
an EXSLT problem, or a Xalan problem (I'm asking too):

http://lists.fourthought.com/pipermail/exslt/2005-July/001256.html

I created a simple testcase to demonstrate the problem, please see the
details below.  If I use the stylesheet version of the function, I don't
encounter this memory issue.

Thanks,

Mike

test.xml (vary the number of 'row' elements)
========
<?xml version="1.0" encoding="ISO-8859-1"?>
<document>
<row>1.2.3.4.5.6.7.8.9.0</row>
</document>
====================================

test.xsl
========
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   xmlns:str="http://exslt.org/strings">

  <xsl:template match="row">
    <xsl:variable name="test" select="str:tokenize(.,'.')"/>
  </xsl:template>
</xsl:stylesheet>
====================================

Command-line:
> java -cp
"C:\tmp\xalan-j_2_7_0\xalan.jar;C:\tmp\xalan-j_2_7_0\serializer.jar;C:\t
mp\xalan-j_2_7_0\xml-apis.jar;C:\tmp\xalan-j_2_7_0\xercesImpl.jar"
-Xmx1024m org.apache.xalan.xslt.Process -IN test.xml -XSL test.xsl -OUT
test_out.xml

Test 1: test.xml with 1,000 rows; file size: 32KB
Result: Transformation completes successfully; maximum process size:
~163MB

Test 2: test.xml with 10,000 rows; file size: 312KB
Result: Transformation aborts with exception; maximum process size:
~900MB

file:///c:/tmp/test.xsl; Line #12; Column #61; XSLT Error
(javax.xml.transform.TransformerException): No more DTM IDs are
available Exception in thread "main" java.lang.RuntimeException: No more
DTM IDs are available
        at org.apache.xalan.xslt.Process.doExit(Process.java:1153)
        at org.apache.xalan.xslt.Process.main(Process.java:1126)

> java -version
java version "1.5.0_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_04-b05)
Java HotSpot(TM) Client VM (build 1.5.0_04-b05, mixed mode, sharing)