sub Prefix {
  my ($m,$n) = (sort @_)[0,-1];
  my $dif = $m ^ $n;
  my $len= length( ( $dif =~ /^(\0*)/ )[0] );
  substr( $m, 0,$len );
}

##</code><code>##

use Benchmark;
@files = qw(model4run1 model2run1 model4run2);

sub antirice {
  my ($m,$n) = (sort @_)[0,-1];
  my $dif= $m ^ $n;
  $len= length( ( $dif =~ /^(\0*)/ )[0] );
  substr( $m, 0,$len );
}

# not picking on Jenda, but he seems to have the fastest prior sub
sub Jenda {
  my $first = shift(@_);
  my $and = $first;
  my $or = $first;
  foreach (@_) {
    $and &= $_;
    $or |= $_;
  }

  my $combined = $and ^ $or;
  $combined =~ s/[^\x00].*//;

  substr($first, 0, length($combined));

}


print "Jenda: " . Jenda(@files) . "\n";
print "antirice: " . antirice(@files) . "\n";

timethese 100000, {
        Jenda => sub {Jenda(@files)},

    antirice => sub {antirice(@files)}
}

__DATA__

Jenda: model
antirice: model
Benchmark: timing 100000 iterations of Jenda, antirice...
     Jenda:  1 wallclock secs ( 0.82 usr +  0.00 sys =  0.82 CPU) @ 121904.76/s (n=100000)
  antirice:  1 wallclock secs ( 0.75 usr +  0.00 sys =  0.75 CPU) @ 133333.33/s (n=100000)