#!/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 $type.\n";
		cmpthese -2 => {
			one_sub => sub { for( 1 .. 1000 ) { s{^N*(.*?)N*$}{$1} for my $copy = $test{$type} } },
			two_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;