use strict;
use warnings;

my $text='Hello World!';

my $hex_text = unpack  'H*', $text;
my @code_points;
while ($hex_text) {
    my $hex_num = substr($hex_text, 0, 5, '');
    push @code_points, hex(sprintf '%05s',$hex_num);
}
my $buffer = pack '(U)*', @code_points;

my @_code_points = unpack('(U)*', $buffer);
my $_hex_text = sprintf '%X' x scalar(@_code_points), @_code_points;
my $_text = pack 'H*', $_hex_text;
print $_text;