#!/usr/bin/perl
# ice-form.pl -- cgi compliant ICE search interface
#
# ICE Version 1.4 beta 3
# July 1997
# (C) Christian Neuss (ice-man@next1.isa.informatik.th-darmstadt.de)

# MAJOR OVERHAUL BY PETE. CALL IT VERSION 1.4P
# NOW USES TEMPLATES
# NOW IGNORES REMOVED COMMON WORDS
# NOW IGNORES TOO SHORT WORDS
# NOW RECOGNISES ABSENCE OF KEYWORDS

#--- start of configuration --- put your changes here ---
# Title or name of your server:
#	 Example: local($title)="Search this server";
local($title)="Search Blather";

# search directories to present in the search dialogue
#	 Example: 
# local(@directories)=(
#		"DZSIM (/www/projects/dzsim)",
#		"CSCW Laboratory (/www/projects/cscw-lab)",
# );

local(@directories)=(
		'Archives (/archives/)',
		'Archives2 (/archives2/)',
		'Archives3 (/archives3/)',
		'Archives4 (/archives4/)',
		'Articles (/articles/)',
		'Articles 2003 (/articles2003/)',
		'Shitegeist (/shitegeist/)',
		'Forteana (/forteana/)',
	         'Bookstore (/bookstore/)',
	          'Gear (/gear/)',
	          'Consulting (/consulting/)',
	);
	
# Location of the indexfile:
#	 Note: under Windows or Windows NT, add the drive letter
#	 Example: $INDEXFILE='/usr/local/etc/httpd/index/index.idx';
$INDEXFILE='/hsphere/local/home/blather/blather.net/search/Index.idx';

# Location of the thesaurus data file:
#	 Example: $thesfile='/igd/a3/home1/neuss/Perl/thes.dat';
#$thesfile='/igd/a3/home1/neuss/Perl/thes.dat';

# Document Root and Aliases for your server. The Document Root is
# the directory where the "top level" documents reside. Additional
# mappings can be set via the "Aliases" variable (which can be left
# empty if no additional mappings exist).
#
# Important hint: if you are unsure about how to set $docroot,
# look at the end of the index file. $docroot must be set so
# that it matches the paths found there.
# Any occurrence of $docroot in the filepath will be substituted
# with a blank.
#
#	 Example
#	 $docroot = '/usr3/webstuff/documents';
#	 %aliases = (
#		 '/projects',	 '/usr/stud/proj', 
#		 '/people',	 '/usr3/webstuff/staff', 
#	 );
#

$docroot = '/hsphere/local/home/blather/blather.net/';
%aliases = ('http://www.blather.net/', '/hsphere/local/home/blather/blather.net/');

# The following configuration settings are OPTIONAL
# HEADER and FOOTER make up the template page.
# Split the template page where you want the
# script to insert forms/results and call the 
# top 'header' and the bottom 'footer'
$HEADER = 'header.txt';
$FOOTER = 'footer.txt';

# Maximum number of hits to return
# Example:
#	 $MAXHITS=100;

# Minimum length of word to be indexed (same as in ice-idx.pl)
# Example:
#	 $MINLEN=3;
$MINLEN=3;

$TEMPLATE = 'test.html';
###########--- end of configuration --- you don't have to change anything below ---#########

# if this script is called up "by hand", run a test
unless($ENV{"SCRIPT_NAME"}){
	local($word) = ($#ARGV==-1) ? "test" : $ARGV[0] ;
	print "You have called the ice forms interface manually.\n";
	print "Optionally, provide search word as an argument.\n";
	print "Test mode: search for \"$word\"\n";
	print "--------\n";
	$orig="$word @ /";
	$foo=&getquery($orig);
	print $foo;
	exit;
}

# do the real work, but trap any errors
eval '&main';

sub main
{

	# if content_length is zero and query string is empty
	if (($ENV{CONTENT_LENGTH}==0) &&
		(length($ENV{"QUERY_STRING"})==0)){
		# we're not decoding a form yet => send the form 
		&send_header("$title");
		&send_index();
		&send_footer();
		return;
	}
	
	# parse forms result and store it in an associative array 
	%forms=&cgiparse();

	&send_header("$title: ICE Query Result");
		
	$query = $forms{KEYWORDS};
	# remove non-word characters
	$query = &html2text($query);
	$query =~ tr/a-zA-Z\xc0-\xff0-9\-/ /cs;
	# remove leading and trailing whitespace
	$query =~ s/^\s*(.*\S)\s*/\1/;
	$pquery = $query;
	$context = $forms{CONTEXT};
		
	if($context =~ m:\(([^)]*)\):) {
		$context=$1;
	}else{
		$context="";
	}
	
	$thesaurus = $forms{THESAURUS};
	$substring = $forms{SUBSTRING};
	
	$days = $forms{DAYS};
	if(length($days)>0){
		$pquery.=" -D $days";
	}
	if(length($thesaurus)>0){
		$pquery.=" -T";
	}
	if(length($substring)>0){
		$pquery.=" -S";
	}
	if(length($context)>0){
		$pquery.=" @ $context";
	}

	if($forms{KEYWORDS})
		{($err,$page) = &getquery($pquery);}
	else
	{
		print '<LI>Please enter some keywords.';
		&send_footer();
		return undef;
	}

	if($err){
		print "Query was: $query<BR>\n";
		print "Problem: $err\n";
		&send_footer();
		return undef;
	}

#	print "Preferences set for this query:\n";
	print "<UL>\n";
	if ($query) {
	 print "<LI> query was \"$query\"\n";
	}
	if($context){
		print "<LI> context was set to $context\n";
	}
	if($thesaurus){
		print "<LI> use of thesaurus turned on\n";
	}
	if($substring){
		print "<LI> substring matching turned on\n";
	}
	if($days){
		print "<LI> changed in the last $days days\n";
	}
	print "</UL>\n";
	if($page){
		print "<P>The index contains the following\n";
		print "items relevant to the query\n";
		print "$page\n";
	}else{
		print "<P> Nothing found.\n";
	}			
 
	&send_footer();
}

# if an error has occured, log it to stdout
if($@)
{
	&send_header("Error in Script"); # just in case
	print "$@\n";
	&send_footer();
}

# print the CGI script header
sub send_header
{
	local($title)=@_;
	print "Content-type: text/html\n\n";
	if($HEADER)
		{$header_dat = `cat $HEADER` || &Error("Couldn't get header $HEADER");}
	else
		{$header_dat = "<HEAD>\n<TITLE>$title</TITLE>\n</HEAD>\n<BODY>\n<H1>$title</H1>\n";}
	print "$header_dat";
}

sub send_footer
{
	if($FOOTER)
		{$footer_dat = `cat $FOOTER` || &Error("Couldn't get footer $FOOTER");}
	else
		{$footer_dat = "</BODY>";}	
	print "$footer_dat";
}

# display the Forms interface 
sub send_index
{

	if($thesfile)
	{
		$THESAURUS_INSERT = 
		'<li><inPUT TYPE="checkbox"
		NAME="THESAURUS" VALUE="thesaurus">
		Use <B>Thesaurus</B> to extend search <BR>';
	}

		local($scriptname) = $ENV{"SCRIPT_NAME"};

		print "<FORM ACTION=\"ice2-for.cgi\">\n";
		print <<"END";

	Find words:
	<blockquote>
	<INPUT NAME="KEYWORDS"	SIZE=30><BR>
	Tip: You can use "and" and "or" with search terms.<BR>
	Example: <I>"cat or mouse".</I><P>
	<INPUT TYPE="submit" VALUE="Start Search">
	</blockquote>
	
	Specify options:
	<ul>

	$THESAURUS_INSERT

	<li><inPUT TYPE="checkbox" NAME="SUBSTRING"
	VALUE="substring"> Use <B>Substring Matching</B> 
	to extend search
	<li><B>Don't Show</B> documents older than 
	<INPUT NAME="DAYS" VALUE="" SIZE=2>	days <BR>
	<li><B>Choose the Area</B> to search:
	<SELECT name="CONTEXT">
	<OPTION> All documents
END
	# if you want the directories visible, uncomment this code and
	# comment out the code below it.
	# thanks to Mark Johnson <Mark.Johnson@InfoHarvest.ab.ca>!
	## foreach $dir (@directories)
	##	{print "<OPTION> $dir\n";}

	foreach $dir (@directories)
	{
		$dir =~ s/\((.*)\)//;
		print "<OPTION VALUE=\"($1)\"> $dir\n";
	}

	print <<'END';
	</SELECT>
	</UL> 
	</FORM>

END
}

# parse data from CGI request and store it as name/value pairs
sub cgiparse
{
	if ($ENV{'REQUEST_METHOD'} eq "POST")
		{read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});}
	else
		{$buffer = $ENV{'QUERY_STRING'};}

	local(@query_strings) = split("&", $buffer);
	foreach $q (@query_strings)
	{
		$q =~ s/\+/ /g;
		($attr, $val) = split("=", $q);
		$val =~ s/%/\n%/g;
		local($tmpval);
		foreach (split("\n",$val))
		{
			if(m:%(\w\w):)
			{
				local($binval) = hex($1);
				if(($binval>0)&&($binval<256))
				{
					local($htmlval) = pack("C",$binval);
					s/%$1/$htmlval/;
				}
			}
			$tmpval .= $_;
		}
		$forms{$attr} = $tmpval;
	}
	%forms;
}


sub getquery
{
	local($query)=@_;
	local($page)="<UL>\n";
	local($hitcount);
	local(@tmplist)= &getindex($query);
	
	
	for $w (@tmplist)
	{
		local($freq,$file,$title,$time,@hits)=split(/\n/,$w);

		local($virt)=&translateback($file);
		$w=join("\n",$freq,$virt,$title,$time,@hits);
	}
	
	sub downbynumber {$b <=> $a;}
	@tmplist = sort downbynumber @tmplist;
	
	foreach $w (@tmplist)
	{
###		&Debug("***<PRE>$w</PRE>***<BR>");
		local($url,$target);
		local($freq,$file,$title,$time,@hits)=split(/\n/,$w);
		if($freq)
		{

			$hitcount++;
			last unless($MAXHITS==0 || $hitcount<=$MAXHITS);
			
			unless($title)
				{ $title="(No document title)"; }
	
			$url = $file;
			
			# change the following lines to localize the result style
			$page .= "<LI> <a $target href=\"$url\">";
			$page .= "$title</A>\n";
			#$page .= "<font size=2>";
			### $page .= "$file\n";	# comment out if you don't want the path
			#$page .= "<blockquote>\n";
			#foreach $line (@hits)
				{$page .= "$line<BR>\n";}
			#$page .= "</font>\n";
			#$page .= "</blockquote>\n";
		}
	}
	
	if($hitcount>0)
		{$page .= "</UL>";}
	else
		{$page = "";}

	("",$page); # return;
}

# parse query
sub parsequery{
	local($query)=@_;
	local($context,$thesaurus,$substr);
	# preprocess whitespace and discard spaces after @ and -D
	$query =~ tr/ \t/ /s;
	$query =~ s/@ /@/g;
	$query =~ s/-D /-D/g;
	$query =~ s/^-D/ -D/g;
	$_=$query;
	# "optional URL context as @-sign"
	if(m:^([^@]*)\s+@(.*)$:){
		$context=$2;
		$_=$1;
	}
	while(m:\s+-[SDT]\d*$:){
		# "turn on "global" thesaurus" by adding -T"
		if(m:^(.*)\s+-T$:){
			$thesaurus="y";
			# print "turn on thesaurus\n";
			$_=$1;
		} 
		# "turn on matching substrings by adding -S"
		if(m:^(.*)\s+-S$:){
			$substr="y";
			# print "turn on substring matching\n";
			$_=$1;
		}
		# "turn on modified since n days" by adding -D"
		if(m:^(.*)\s+-D(\d+)$:){
			$days=$2;
			# print "turn on modified since $days\n";
			$_=$1;
		}
	} 

	@list=split(/ /,$_);

	$expectword="y" unless($days && $#list==-1);
	foreach $w (@list){
		$_ = $w;
		tr/A-Z/a-z/;
		if(/^and$/) {
			if($expectword) {$err="$w"; last;}
			$expectword="y";
			$bool .= "&";
		}elsif(/^or$/){
			if($expectword) {$err="$w"; last;}
			$expectword="y";
			$bool .= "+";
		}else{
			unless($expectword) {
				$bool .= "&";
			}
			$expectword="";
			push(@querystring,$w); 
		}
	}
	if($expectword){
		print ("syntax error in query: must end with keyword!");
	}
	if($err){
		print ("syntax error in query near '$err'!");
	}
	
	return($context,$thesaurus,$substr,$bool,$days,@querystring);
}

# get index entries matching query
sub getindex
{
	local($context,$thes,$substr,$bool,$days,@query) = &parsequery(@_);
	local(@list,$count,$item,$w,@wordnum,$grepexpr,$ret);
	local($limit,@allids,@keywords);
	if($days)
		{$limit=time()-(60*60*24*$days) unless($days==0);}

	foreach $item (@query){
		++$count;
		local($w);
		$_=$item;
		local($thesflag)=$thes;
		if (/{(.*)}/) {
			$_ = $1;
			$thesflag="y";
		}
		# convert e.g. "Picture" to "picture"
		if(/^[A-Z][^A-Z]*$/){
			tr/A-Z/a-z/;
		}
		# evaluate thesaurus
		if ($thesflag) {
			$wordnum{$_}=$count;
			local(@synonyms)=split(/\n/,&thesread($thesfile,$_));
			foreach $w (@synonyms){
				push (@keywords,$w);
				$wordnum{$w}=$count;
			}
		} 
		if(length($_)<$MINLEN) {
			print "ignored: $_ (too short)<br>\n";
			push(@ignored,$count);
		}else{
			$w=$_;
			push (@keywords,$w);
			$wordnum{$w}=$count;	
		}
	}

	$grepexpr = join("|",@keywords);
	# trick for speedup: if no keywords, set grepexpr to "^--"
	$grepexpr = "^--" unless(@keywords > 0);

	if(@keywords <=0)
		{return;}

	local($timstr,$pat);
	open(FP,"$INDEXFILE") || die "$!";
	while(<FP>){
		if(/^--/o){ # seperator
			last; # break loop
		}
		next unless (/$grepexpr/o);
		foreach $w (@keywords){
			$pat = $substr ? '\S*'.$w.'\S*' : $w;
			if(/^($pat)\s+(.*)$/){
				$word=$1;
				@files=split(/ /,$2);
				foreach (@files){
		if(/(.*):(.*)/ || /(.)(.*)/){
						$freq=$1; $fileid=$2;
					}
		if (length($word)>0) {
			if (hex($fileid) != 0) {
							$token=$wordnum{$w};
							$entry=join("\n",$fileid,$token,$word,$freq);
				push(@allids,$fileid);
							push(@list,$entry);
						} elsif ($word eq $w) {
							$token=$wordnum{$w};
							print "ignored: $word (stopword)<br>\n";
							push(@ignored,$token);
			}
		}
				}
			}
		}
	}
	# step 2: read path information
	$grepexpr = join("|",@allids);
	$grepexpr = '\S+' unless (@keywords>0); # match all if none given

	local($name,$fileid);
	while(<FP>){
		if(m:^(/.*):){
			$dir = $1;
		}
		if(/^($grepexpr)\s+(.*) \/(\S+)\s+(.*)$/o){
			$fileid = $1;
			$name = "$dir/$2";
			$mtime = $3;
			$title = $4;
			# special case: no keywords -> get all files matching $limit
			 if(@keywords == 0 && $mtime>=$limit){
				 $entry = join("\n",$name,"","","",$title,$mtime);
				 push(@list,$entry);
				 next; # continue loop
			}
			# if file doesn't match $limit
			if($limit != 0 && $mtime<$limit){
				# remove it from list
				@list = grep(!/^$fileid\n/,@list);
			}
			# else replace fileid in @list with real path
			else{
				foreach(@list){
					if(/^$fileid\n/){
						s/^$fileid\n/$name\n/; # replace id with real path
						$_ .= "\n$title"; # append title
						$_ .= "\n$mtime"; # append mod. time
					}
				}
			}
		}
	}
	close(FP);

	if($context){
		# translate virtual<->physical path
		local($virt,$phys)=($context,&translate($context));
		#&Debug("CONTEXT: virt:$virt phys:$phys");
		# remove those paths that don't match context
		@list=grep(/$phys/,@list);
	}

	if($#keywords>=0){
		# if keywords given evaluate expression
		@list=sort(@list);
		&evaluateexpr($bool,@list); #return
	}else{
		# else just reorder
		foreach $w (@list){
			($path,$token,$word,$freq,$title,$time)=split(/\n/,$w);
			$w=join("\n","1",$path,$title,&timetostr($time));
		}

		@list;
	}
}

sub evaluateexpr {
	local($bool,@list)=@_;
	local($lastpath,$lasttitle,$lasttime,$retval);
	local($relevance,%wordlist);
	local(@reslist);
	
	# let's do some initialisation
	($path,$token,$word,$freq,$title,$mtime)=split(/\n/,$list[0]);
	$lastpath=$path;
	$lasttitle=$title;
	$lasttime=$mtime;
	%wordlist=();
	local($fw);
	if($word ne $query[$token-1]){
		$fw="$freq ($query[$token-1])";
	}else{
		$fw="$freq";
	}
	$wordlist{$word}=$fw;
	foreach $i (0 .. $#query){
		$exprarray[$i]=0;
	}
	# all stopwords are ignored (treated as matches)
	foreach (@ignored) {
		$exprarray[$_-1]=1;
	}

	
	# loop over all entries in list
	foreach $i (0 .. $#list+1){ # sic!
		if($i <= $#list){
			($path,$token,$word,$freq,$title,$mtime)=split(/\n/,$list[$i]);
		} 
		# if path has changed -> compute expression
		if(($lastpath ne $path) || ($i==$#list+1)) {
			$expr=join('',@exprarray);
			###print "path changed, call $exprarray ($expr) and ($bool)\n";
			local($ret)=&booleval($bool,$expr);
			if($ret==1){
				local($w);
				$retval .= "$relevance\n";
				$retval .= "$lastpath\n";
				$retval .= "$lasttitle\n";
				$retval .= &timetostr($lasttime)."\n";
				foreach $w (sort keys(%wordlist)){
					$retval .= "\"$w\" $wordlist{$w}\n";
				}
				push(@reslist,$retval);
				$retval="";
			}
			if($i==$#list+1){
				last; # leave loop
			}
			$lastpath=$path;
			$lasttitle=$title;
			$lasttime=$mtime;
			$relevance=$freq;
			%wordlist=();
			if($word ne $query[$token-1]){
				$fw="$freq ($query[$token-1])";
			}else{
				$fw="$freq";
			}
			$wordlist{$word}=$fw;
			foreach $i (0 .. $#query){
				$exprarray[$i]=0;
			}
			# all stopwords are ignored (treated as matches)
			foreach (@ignored) {
				$exprarray[$_-1]=1;
			}
			$exprarray[$token-1]=1;
		}else{
			$exprarray[$token-1]=1;
			$relevance += $freq;
			if($word ne $query[$token-1]){
				$fw="$freq ($query[$token-1])";
			}else{
				$fw="$freq";
			}
			$wordlist{$word}=$fw;
		}
	}
	@reslist; # return;
}

# compute boolean expressions
# e.g. to compute "1 or 0 and 1" use booleval("101","+&")
sub booleval {
	local($arg1,$arg2)=@_;
	local($t1,$t2,$i,$op,$opers,$terms);
	@opers=split(//,$arg1);
	@terms=split(//,$arg2);

	$t1=$terms[0];
	if($#terms==0){ # only one term given
		return $t1;
	}
	for $i (0..($#terms-1)){
		$t2=$terms[$i+1];
		$op=$opers[$i];
		if($op eq "+"){
			if($t1!=0){ 
				return 1;
			} else {
				$t1=$t2;
			}
		}else{
			$t1*=$t2;
		}
	}
	return $t1;
}

# evaulate a thesaurus file for a given term
sub thesread {
	local($thesfile,$word)=@_;
	local($last,$result,$line)="";
	local($allowed)="EQ|AB|UF";
	unless (open(fpin,$thesfile)) {
		print STDERR "Cannot open thesaurus file $thesfile\n";
		return undef;
	}
	while(<fpin>){
		$line++;
		if (m:^(\S+)\s+$:) {
			$last=$1;
		}elsif((m:^\s+($allowed)\s+(\S+):)&&($last eq $word)) {
			$result .= "$2\n";
		}
	}
	close(fpin);
	$result;
}

# translate URL to physical
sub translate {
	local($url)=@_;
	local($aliasdone);
	local($_)=$url;

	s|/+$||; # strip off a trailing "/"

	foreach $key (keys(%aliases)){
		if( /^$key/ ){
			s/^$key/$aliases{$key}/;
			$aliasdone="y";
			#&Debug("replacing $key with $aliases{$key}");
		}
	}
	if(!$aliasdone && $docroot){
		$_ = $docroot.$_;
	}
	return $_;
}

# translate physical to URL
sub translateback {
	local($url)=@_;
	local($aliasdone);
	local($_)=$url;
	s/(.*)\/$/\1/; # strip off a trailing "/"

	foreach $key (keys(%aliases)){
		if(/^$aliases{$key}/){
			s/^$aliases{$key}/$key/;
			$aliasdone="y";
			#&Debug("replacing $aliases{$key} with $key");
		}
	}
	if(!$aliasdone && $docroot)
	{s/$docroot//;}
	return $_;
}

# convert time to string
sub timetostr
{
	local($time)=@_;
	local($sec,$min,$hour,$mday,$mon,$year,$wday,@dontcare)=localtime($time);
	local($weekday)=(Sun,Mon,Tue,Wed,Thu,Fri,Sat)[$wday];
	local($month)=(Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec)[$mon];
	local($result)="$weekday $mday $month $year";
	$result;
}

# iso2html - translate iso 8 bit characters to HTML
#
# Thanks to
# Pierre Cormier (cormier.pierre@uqam.ca)
# Universite du Quebec Montreal
sub initTables
{
	foreach (0..191)
		{ $isohtml[$_] = pack("C",$_);}
	$isohtml[hex('c0')] = '&Agrave;';
	$isohtml[hex('c1')] = '&Aacute;';
	$isohtml[hex('c2')] = '&Acirc;';
	$isohtml[hex('c3')] = '&Atilde;';
	$isohtml[hex('c4')] = '&Auml;';
	$isohtml[hex('c5')] = '&Aring;';
	$isohtml[hex('c6')] = '&AElig;';
	$isohtml[hex('c7')] = '&Ccedil;';
	$isohtml[hex('c8')] = '&Egrave;';
	$isohtml[hex('c9')] = '&Eacute;';
	$isohtml[hex('ca')] = '&Ecirc;';
	$isohtml[hex('cb')] = '&Euml;';
	$isohtml[hex('cc')] = '&Igrave;';
	$isohtml[hex('cd')] = '&Iacute;';
	$isohtml[hex('ce')] = '&Icirc;';
	$isohtml[hex('cf')] = '&Iuml;';
	$isohtml[hex('d0')] = '&ETH;';
	$isohtml[hex('d1')] = '&Ntilde;';
	$isohtml[hex('d2')] = '&Ograve;';
	$isohtml[hex('d3')] = '&Oacute;';
	$isohtml[hex('d4')] = '&Ocirc;';
	$isohtml[hex('d5')] = '&Otilde;';
	$isohtml[hex('d6')] = '&Ouml;';
	$isohtml[hex('d7')] = '&times;';
	$isohtml[hex('d8')] = '&Oslash;';
	$isohtml[hex('d9')] = '&Ugrave;';
	$isohtml[hex('da')] = '&Uacute;';
	$isohtml[hex('db')] = '&Ucirc;';
	$isohtml[hex('dc')] = '&Uuml;';
	$isohtml[hex('dd')] = '&Yacute;';
	$isohtml[hex('de')] = '&THORN;';
	$isohtml[hex('df')] = '&szlig;';
	$isohtml[hex('e0')] = '&agrave;';
	$isohtml[hex('e1')] = '&aacute;';
	$isohtml[hex('e2')] = '&acirc;';
	$isohtml[hex('e3')] = '&atilde;';
	$isohtml[hex('e4')] = '&auml;';
	$isohtml[hex('e5')] = '&aring;';
	$isohtml[hex('e6')] = '&aelig;';
	$isohtml[hex('e7')] = '&ccedil;';
	$isohtml[hex('e8')] = '&egrave;';
	$isohtml[hex('e9')] = '&eacute;';
	$isohtml[hex('ea')] = '&ecirc;';
	$isohtml[hex('eb')] = '&euml;';
	$isohtml[hex('ec')] = '&igrave;';
	$isohtml[hex('ed')] = '&iacute;';
	$isohtml[hex('ee')] = '&icirc;';
	$isohtml[hex('ef')] = '&iuml;';
	$isohtml[hex('f0')] = '&eth;';
	$isohtml[hex('f1')] = '&ntilde;';
	$isohtml[hex('f2')] = '&ograve;';
	$isohtml[hex('f3')] = '&oacute;';
	$isohtml[hex('f4')] = '&ocirc;';
	$isohtml[hex('f5')] = '&otilde;';
	$isohtml[hex('f6')] = '&ouml;';
	$isohtml[hex('f7')] = '&DIVIS;';
	$isohtml[hex('f8')] = '&oslash;';
	$isohtml[hex('f9')] = '&ugrave;';
	$isohtml[hex('fa')] = '&uacute;';
	$isohtml[hex('fb')] = '&ucirc;';
	$isohtml[hex('fc')] = '&uuml;';
	$isohtml[hex('fd')] = '&yacute;';
	$isohtml[hex('fe')] = '&thorn;';
	$isohtml[hex('ff')] = '&yuml;';

	# preset iso2text variable settings
	foreach (0..191)
		{ $iso2text[$_] = pack("C",$_);}
	foreach (hex('c0')..hex('ff'))
		{$iso2text[$_] = substr($isohtml[$_],1,1);}
	# now assign exceptions:
	$iso2text[hex('c4')] = 'Ae';
	$iso2text[hex('c6')] = 'AE';
	$iso2text[hex('d0')] = 'ETH'; # ???
	$iso2text[hex('d6')] = 'Oe';
	$iso2text[hex('d7')] = 'x';
	$iso2text[hex('dc')] = 'Ue';
	$iso2text[hex('de')] = 'Th'; # thorn ???
	$iso2text[hex('df')] = 'sz';
	$iso2text[hex('e4')] = 'ae';
	$iso2text[hex('e6')] = 'ae';
	$iso2text[hex('f7')] = 'D';	# Divis?
	$iso2text[hex('fc')] = 'ue';
	$iso2text[hex('fe')] = 'th'; #	thorn

	# set html2iso variable
	foreach (1..255)
		{$html2iso{$isohtml[$_]}=pack("C",$_);;}
}

sub iso2html
{
	local($input)=@_;
	unless(defined($isohtml[0]))
		{&initTables;}
	local(@car) = split(//,$input);
	local($output);
	foreach (@car)
		{$output .= $isohtml[ord($_)];}
	$output;
}

sub iso2text
{
	local($input)=@_;
	unless(defined($isohtml[0]))
		{&initTables;}
	local(@car) = split(//,$input);
	local($output);
	foreach (@car)
		{$output .= $iso2text[ord($_)];}
	$output;
}

sub html2iso
{
	local($input)=@_;
	unless(defined($isohtml[0]))
		{&initTables;}
	local(@car) = split(/;/,$input);
	local($output);
	foreach (@car)
	{
		if(/(.*)&(.*)/)
		{
			$output .= $1;
			$output .= $html2iso{"&$2;"};
		}
		else
			{$output .= $_;}
	}
	$output;
}

sub html2text
{
	return &iso2text(&html2iso(@_));
}

sub Debug
{
# DUMPS A STRING TO A BROWSER AS HTML
	if(!$DEBUG_USED)
		{print "Content-type: text/html\n\n";}
	$DEBUG_USED = 1;
	print "<LI>$_[0]";
}

sub Error    
{
# RETURNS A USER LEVEL ERROR MESSAGE WITH THE SYSTEM HEADER AND FOOTERS
        print "Content-type: text/html\n\n";
        print"<H3>Error</H3>$_[0]";
        exit;
}