use warnings;
use strict;

use Benchmark qw(cmpthese);


my $multiplier = 10_000;
my $s__ = "abcdefghij" x $multiplier;  # base string
my $s10 = "Abcdefghij" x $multiplier;  # 10% differ
my $s50 = "ABCDEfghij" x $multiplier;  # 50% differ
my $s90 = "ABCDEFGHIj" x $multiplier;  # 90% differ


sub differ_at_rx {
    my $diff = $_[0] ^ $_[1];
    my @diffs;
    push @diffs, $-[1] while $diff =~ m{ ([^\000]) }xmsg;
    return \@diffs;
    }

sub differ_at_up {
    my @diffs = unpack 'C*', $_[0] ^ $_[1];
    return [ grep $diffs[$_], 0 .. $#diffs ];
    }


print "multiplier == $multiplier \n";
cmpthese(-10, {
    up_10 => sub { differ_at_up($s__, $s10) },
    up_50 => sub { differ_at_up($s__, $s50) },
    up_90 => sub { differ_at_up($s__, $s90) },
    rx_10 => sub { differ_at_rx($s__, $s10) },
    rx_50 => sub { differ_at_rx($s__, $s50) },
    rx_90 => sub { differ_at_rx($s__, $s90) },
    });