my $str = "abcdefgh12345678" x 20;
my $strlen = length $str;


cmpthese(50000, {

'grep_split' => sub 
{
  my @arr = grep {$_} split /(.{8})/, $str;
},

'split_pos' => sub
{
  my @arr = split /(?(?{pos() % 8})(?!))/, $str;
},

'substr_map' => sub
{
	my $len = length $str;
  my @arr = map {substr($str, $_ * 8, 8)} (0 .. $strlen / 8 - 1);
},

'substr_loop' => sub
{
  my @arr;
  my $len = length $str;
  for (my $i = 0; $i < $len; $i += 8)
  {
    push(@arr, substr($str, $i, 8));
  }
},

'unpack' => sub 
{
  my @arr = unpack('(A8)*', $str);
}
});