=head2 icecast_listeners($url, $stream_name)

    icecast_listeners('http://localhost:8000/status-text.xsl', '/stream');

The URL provided should point to a comma-delimited status file served by
icecast in the format:

    MountPoint,Connections,Stream Name,Current Listeners,Description,Currently Playing,Stream URL

As long as the MountPoint and Stream Name don't have any embedded commas
in them, the (simplistic) parsing should work fine.  Fixing the regexes
if this isn't suitable is left as an exercise for the reader.  ; )

Returns undef on error and the number of listeners for the stream
specified on success, or if no stream is specified, the listeners for
all streams.

=cut

sub icecast_listeners {
    my ($url, $stream) = @_;
    
    # get data
    use LWP::Simple qw/get/;
    my $data = LWP::Simple::get($url) or return undef;
    $data =~ s/<br>/\n/g;
    my @data = split /\n/, $data;
    
    if ($stream) {
        # getting just one stream
        for (@data) {
            next unless /^\Q$stream\E/;
            /^\Q$stream\E,\d+,[^,]*,(\d+),/;
            return $1 ? $1 : 0;
        }
    } else {
        # get total listeners for server
        my $total = 0;
        for (@data) {
            next unless /^\//;
            /^\/[^,]+,\d+,[^,]*,(\d+),/;
            $total += $1 if $1;
        }
        return $total ? $total : 0;
    }
    return undef;
}