string-to-codepoints(string) equivalent in XSLT 1.0 - xslt

Question

I need to get ASCII value of character and Convert ASCII code back to character if it satisfies certain conditions.
So I came across these functions:
string-to-codepoints(string)
and
codepoints-to-string((int,int,...))
provided in XSLT 2.0 (Or Rather XPATH 2.0) But unfortunately I need to use XSLT 1.0 for this task.
So My question is
Is there any equivalent of these functions in XSLT 1.0? If not Can we design it?
Can experts here help me in that?
Thanks in advance

Answer 1

It is possible to replace all characters with codepoints above 255 by "?" using pure XSLT 1.0 without extensions.
Define a variable
<xsl:variable name="upto255">
!"#$%.../01234...ABC...abc...úûüýþÿ</xsl:variable>
whose value is a string containing all the characters in the range 0..255 that are legal in XML.
Then use the double-translate trick:
<xsl:variable name="above255" select="translate($input, $upto255, '')"/>
This variable is a string containing all the non-Latin-1 characters present in the input string. Then use the recursive template
<xsl:template name="pad">
<xsl:param name="char"/>
<xsl:param name="count"/>
<xsl:choose>
<xsl:when test="$count=0"/>
<xsl:otherwise>
<xsl:value-of select="$char"/>
<xsl:call-template name="pad">
<xsl:with-param name="char" select="$char"/>
<xsl:with-param name="count" select="$count - 1"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
to create a string of the right number of question marks:
<xsl:variable name="qqq">
<xsl:call-template name="pad">
<xsl:with-param name="char" select="'?'"/>
<xsl:with-param name="count" select="string-length($above255)"/>
</xsl:call-template>
</xsl:variable>
and then do the substitution:
<xsl:value-of select="translate($input, $above255, $qqq)"/>
But of course since you are in Java there is no excuse for writing all this XSLT 1.0 code which could be replaced by a single line of code if you switched to an XSLT 2.0 processor such as Saxon.

Answer 2

Based on your comments you want to perform a string replacement based on a regular expression. If you are using Java and Xalan then I think you can use e.g. java:replaceAll($inputString, $regExpPattern, $replacementString) to call the Java String method replaceAll, here is a simple example
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:java="http://xml.apache.org/xalan/java"
version="1.0"
exclude-result-prefixes="java">
<xsl:template match="/">
<xsl:value-of select="java:replaceAll('abc-123-def','\w+', '?')"/>
</xsl:template>
</xsl:stylesheet>
which outputs ?-?-? for me with Xalan.
On the other hand if you are using Java then you should consider moving to Saxon 9 and XSLT 2.0 as that way you can use the XPath 2.0 replace function (replace('abc-123-def', '\w+', '?')) without any need for extensions.
I am not sure what that has to do with your original question about string-to-codepoints and the ASCII code of characters.