decrease recursive depth

scubin · January 8th, 2010, 06:36 PM

Hi ,
Can anyone help to improvise this code to reduce recursion depth.It is giving stack overflow if the input-string lenght.greter than 10000.the below template is for removing trailing spaces.

Thanks

HTML Code:

<xsl:template match="@*|node()">
- <xsl:copy>
  <xsl:apply-templates select="@*|node()" /> 
  </xsl:copy>
  </xsl:template>
- <xsl:template match="*">
- <xsl:copy>
  <xsl:apply-templates select="@*" /> 
- <xsl:choose>
- <xsl:when test="not(*)">
- <xsl:variable name="new-value">
- <xsl:call-template name="remove-trailing-char">
  <xsl:with-param name="input-string" select="." /> 
  <xsl:with-param name="word" select="' '" /> 
  </xsl:call-template>
  </xsl:variable>
  <xsl:value-of select="$new-value" /> 
  </xsl:when>
- <xsl:otherwise>
  <xsl:apply-templates select="*" /> 
  </xsl:otherwise>
  </xsl:choose>
  </xsl:copy>
  </xsl:template>
- <xsl:template name="remove-trailing-char">
  <xsl:param name="input-string" /> 
  <xsl:param name="word" /> 
  <xsl:variable name="last-char" select="substring($input-string, string-length($input-string), 1)" /> 
- <xsl:choose>
- <xsl:when test="not($last-char='') and contains($word, $last-char)">
- <xsl:call-template name="remove-trailing-char">
  <xsl:with-param name="input-string" select="substring($input-string, 1, string-length($input-string)-1)" /> 
  <xsl:with-param name="word" select="$word" /> 
  </xsl:call-template>
  </xsl:when>
- <xsl:otherwise>
  <xsl:value-of select="$input-string" /> 
  </xsl:otherwise>
  </xsl:choose>
  </xsl:template>

mhkay · January 8th, 2010, 08:36 PM

Well, in an ideal world you could use an XSLT 2.0 processor, or failing that, an XSLT 1.0 processor that implements tail recursion. But if you can't do either of those things then (assuming you only want to solve the specific problem of removing trailing spaces, rather than the more general functionality of your remove-trailing-char template) you could try a divide-and-conquer approach like this:

Find the mid-point of the string. If the rhs is all spaces, make a recursive call to process the lhs. Otherwise, copy the lhs and make a recursive call to process the rhs. The test whether a string is all spaces is not(normalize-space($X)).

This gives you a max recursive depth of log(N) where N is the string length.

scubin · January 8th, 2010, 11:04 PM

Excellent thanks Kay,was able to resolve it using the divide and conquer approach