Convert plain text to HTML&XML escaped entities w/ Perl

sub xmlize {

       # unpack byte-by-byte (set to "U0U*" in case of UTF-8)

        my $format="C*"; 
           my @output;

        while($line=shift @_) {

                my @array=map {

                        if($_>127) {

                                sprintf("&#%04ld;",$_);

                        }

                        else {

                                sprintf("%s",chr($_));

                        }

                }unpack($format,$line);

                push(@output,join "", @array);

        }

        return join "",@output;

}