Что тут происходит?

Code:

sub process_tripcode($;$$$$)
{
 my ($name,$tripkey,$secret,$charset,$nonamedecoding)=@_;
 $tripkey="!" unless($tripkey);

 if($name=~/^(.*?)((?<!&)#|\Q$tripkey\E)(.*)$/)
 {
 my ($namepart,$marker,$trippart)=($1,$2,$3);
 my $trip;

 $namepart=decode_string($namepart,$charset) unless $nonamedecoding;
 $namepart=clean_string($namepart);

 if($secret and $trippart=~s/(?:\Q$marker\E)(?<!&#)(?:\Q$marker\E)*(.*)$//) # do we want secure trips, and is there one?
 {
 my $str=$1;
 my $maxlen=255-length($secret);
 $str=substr $str,0,$maxlen if(length($str)>$maxlen);
 #$trip=$tripkey.$tripkey.encode_base64(rc4(null_string(6),"t".$str.$secret),"
");
 $trip=$tripkey.$tripkey.hide_data($1,6,"trip",$secret,1);
 return ($namepart,$trip) unless($trippart); # return directly if there's no normal tripcode
 }

 # trips are processed as Shift_JIS whenever possible
 eval 'use Encode qw(decode encode)';
 unless($@)
 {
 $trippart=decode_string($trippart,$charset);
 $trippart=encode("Shift_JIS",$trippart,0x0200);
 }

 $trippart=clean_string($trippart);
 my $salt=substr $trippart."H..",1,2;
 $salt=~s/[^\.-z]/./g;
 $salt=~tr/:;<=>?@[\\]^_`/ABCDEFGabcdef/; 
 $trip=$tripkey.(substr crypt($trippart,$salt),-10).$trip;

 return ($namepart,$trip);
 }

 return clean_string($name) if $nonamedecoding;
 return (clean_string(decode_string($name,$charset)),"");
}


sub decode_string($;$$)
{
	my ($str,$charset,$noentities)=@_;
	my $use_unicode=$has_encode && $charset;

	$str=decode($charset,$str) if $use_unicode;

	$str=~s{(&#([0-9]*)([;&])|&#([x&])([0-9a-f]*)([;&]))}{
		my $ord=($2 or hex $5);
		if($3 eq '&' or $4 eq '&' or $5 eq '&') { $1 } # nested entities, leave as-is.
		elsif(forbidden_unicode($2,$5))  { "" } # strip forbidden unicode chars
		elsif($ord==35 or $ord==38) { $1 } # don't convert & or #
		elsif($use_unicode) { chr $ord } # if we have unicode support, convert all entities
		elsif($ord<128) { chr $ord } # otherwise just convert ASCII-range entities
		else { $1 } # and leave the rest as-is.
	}gei unless $noentities;

	$str=~s/[\x00-\x08\x0b\x0c\x0e-\x1f]//g; # remove control chars

	return $str;
}


sub clean_string($;$)
{
	my ($str,$cleanentities)=@_;

	if($cleanentities) { $str=~s/&/&amp;/g } # clean up &
	else
	{
		$str=~s/&(#([0-9]+);|#x([0-9a-fA-F]+);|)/
			if($1 eq "") { '&amp;' } # change simple ampersands
			elsif(forbidden_unicode($2,$3))  { "" } # strip forbidden unicode chars
			else { "&$1" } # and leave the rest as-is.
		/ge  # clean up &, excluding numerical entities
	}

	$str=~s/\</&lt;/g; # clean up brackets for HTML tags
	$str=~s/\>/&gt;/g;
	$str=~s/"/&quot;/g; # clean up quotes for HTML attributes
	$str=~s/'/'/g;
	$str=~s/,/,/g; # clean up commas for some reason I forgot

	$str=~s/[\x00-\x08\x0b\x0c\x0e-\x1f]//g; # remove control chars

	return $str;
}

 

Обрабатывается трипкод

Что в точности происходит сказать нельзя, потому что неизвестны функции decode_string, clean_string...