#!/usr/bin/perl
use strict;
use warnings;

use Benchmark qw( cmpthese );

sub run_tests {
    my ( $len_remove, $len_keep, $num_repeat ) = @_;

    my $remove = 'N' x $len_remove;
    my $keep = 'O' x $len_keep;

    my %test = (
        front     => "$remove$keep" x $num_repeat,
        tail      => "$keep$remove" x $num_repeat,
        both_ends => "$remove$keep" x $num_repeat . $remove,
        nothing   => "$keep$remove" x $num_repeat . $keep,
    );

    print "$len_remove chars to remove, $len_keep chars long kept sequences, $num_repeat repetitions.\n";
    for my $type ( keys %test ) {
        print "Measuring removing at $type.\n";
        cmpthese -2 => {
            two_sub => sub { for( 1 .. 1000 ) { s{^N*(.*?)N*$}{$1} for my $copy = $test{$type} } },
            one_sub => sub { for( 1 .. 1000 ) { s{^N*}{}, s{N*$}{} for my $copy = $test{$type} } },
        };
    }

    print "\n";
}

$|++;

run_tests 4, 4, 1;
run_tests 20, 20, 1;
run_tests 20, 20, 50;
run_tests 4, 4, 20;
run_tests 4, 12, 10;
run_tests 4, 100, 100;
__END__
P:\test>junk3
4 chars to remove, 4 chars long kept sequences, 1 repetitions.
Measuring removing at front.
         Rate two_sub one_sub
two_sub 101/s      --    -64%
one_sub 279/s    177%      --
Measuring removing at tail.
         Rate two_sub one_sub
two_sub 103/s      --    -64%
one_sub 284/s    176%      --
Measuring removing at nothing.
          Rate two_sub one_sub
two_sub 98.5/s      --    -54%
one_sub  215/s    118%      --
Measuring removing at both_ends.
          Rate two_sub one_sub
two_sub 97.2/s      --    -64%
one_sub  269/s    177%      --

20 chars to remove, 20 chars long kept sequences, 1 repetitions.
Measuring removing at front.
          Rate two_sub one_sub
two_sub 81.8/s      --    -49%
one_sub  160/s     96%      --
Measuring removing at tail.
          Rate two_sub one_sub
two_sub 83.7/s      --    -49%
one_sub  164/s     96%      --
Measuring removing at nothing.
          Rate two_sub one_sub
two_sub 60.4/s      --    -29%
one_sub 85.0/s     41%      --
Measuring removing at both_ends.
          Rate two_sub one_sub
two_sub 77.6/s      --    -55%
one_sub  172/s    121%      --

20 chars to remove, 20 chars long kept sequences, 50 repetitions.
Measuring removing at front.
          Rate one_sub two_sub
one_sub 3.47/s      --     -8%
two_sub 3.77/s      8%      --
Measuring removing at tail.
          Rate one_sub two_sub
one_sub 3.44/s      --     -7%
two_sub 3.71/s      8%      --
Measuring removing at nothing.
          Rate one_sub two_sub
one_sub 3.47/s      --     -6%
two_sub 3.68/s      6%      --
Measuring removing at both_ends.
          Rate one_sub two_sub
one_sub 3.56/s      --     -5%
two_sub 3.74/s      5%      --

4 chars to remove, 4 chars long kept sequences, 20 repetitions.
Measuring removing at front.
          Rate two_sub one_sub
two_sub 34.1/s      --    -17%
one_sub 41.1/s     20%      --
Measuring removing at tail.
          Rate two_sub one_sub
two_sub 35.1/s      --    -14%
one_sub 41.0/s     17%      --
Measuring removing at nothing.
          Rate two_sub one_sub
two_sub 34.1/s      --    -12%
one_sub 38.9/s     14%      --
Measuring removing at both_ends.
          Rate two_sub one_sub
two_sub 33.6/s      --    -18%
one_sub 41.1/s     22%      --

4 chars to remove, 12 chars long kept sequences, 10 repetitions.
Measuring removing at front.
          Rate two_sub one_sub
two_sub 35.2/s      --    -15%
one_sub 41.2/s     17%      --
Measuring removing at tail.
          Rate two_sub one_sub
two_sub 35.2/s      --    -16%
one_sub 41.7/s     19%      --
Measuring removing at nothing.
          Rate two_sub one_sub
two_sub 30.6/s      --    -18%
one_sub 37.2/s     22%      --
Measuring removing at both_ends.
          Rate two_sub one_sub
two_sub 34.4/s      --    -17%
one_sub 41.5/s     21%      --

4 chars to remove, 100 chars long kept sequences, 100 repetitions.
Measuring removing at front.
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
        s/iter one_sub two_sub
one_sub   1.44      --    -10%
two_sub   1.29     11%      --
Measuring removing at tail.
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
        s/iter one_sub two_sub
one_sub   1.43      --    -11%
two_sub   1.27     12%      --
Measuring removing at nothing.
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
        s/iter one_sub two_sub
one_sub   1.45      --    -13%
two_sub   1.27     15%      --
Measuring removing at both_ends.
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
        s/iter one_sub two_sub
one_sub   1.46      --    -13%
two_sub   1.27     15%      --