#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw(cmpthese timethese);

my $char = 'a';
my %hash = map {$char++.$_ => $_} (1..50);
my %HoH = map {$char++.$_ => {%hash} } (1..20);
my %HoHoH = map {$char++.$_ => {%HoH} } (1..50);

my ($ref,$ref1,$ref2,$ref3,$ref4);
$ref1->{key1} = {%hash};
$ref2->{key1}{key2} = {%hash};
$ref3->{key1}{key2}{key3} = {%hash};
$ref4->{key1}{key2}{key3}{key4} = {%hash};

my ($shortref,$shortref1,$shortref2,$shortref3,$shortref4) = (
			\%hash,
			$ref1->{key1},
			$ref2->{key1}{key2},
			$ref3->{key1}{key2}{key3},
			$ref4->{key1}{key2}{key3}{key4},
	);

my $iterations = 10000;
my @benchmarks = (
			{count=> $iterations, hash=>sub { foreach my $k ( keys %hash ) { $hash{$k}++ } },
			 ref=>sub { foreach my $k ( keys %{$shortref} ) { $shortref->{$k}++ } } },

			{count=> $iterations, ref2hash1=>sub { foreach my $k ( keys %{$ref1->{key1}}) { $ref1->{key1}{$k}++ }},
			 shortref1=>sub { foreach my $k ( keys %{$shortref1}) { $shortref1->{$k}++ }} },

			{count=> $iterations, ref2hash2=>sub { foreach my $k ( keys %{$ref2->{key1}{key2}}) { $ref2->{key1}{key2}{$k}++ }},
			 shortref2=>sub { foreach my $k ( keys %{$shortref2}) { $shortref2->{$k}++ }} },
			
			{count=> $iterations, ref2hash3=>sub { foreach my $k ( keys %{$ref3->{key1}{key2}{key3}}) { $ref3->{key1}{key2}{key3}{$k}++ }},
			 shortref3=>sub { foreach my $k ( keys %{$shortref3}) { $shortref3->{$k}++ }} },
			
			{count=> $iterations, ref2hash4=>sub { foreach my $k ( keys %{$ref4->{key1}{key2}{key3}{key4}}) { $ref4->{key1}{key2}{key3}{key4}{$k}++ }},
			 shortref4=>sub { foreach my $k ( keys %{$shortref4}) { $shortref4->{$k}++ }} },

			{
				count=>2000,
				HoH =>sub { 
							foreach my $k (keys %HoH) {
								 foreach (keys %{ $HoH{$k} } ){
									$HoH{$k}->{$_}++;
								 }
							}
						},
				refHoH =>sub { 
							foreach my $k (keys %HoH) {
								 my $hashref = $HoH{$k};
								 foreach (keys %{ $hashref } ){
									$hashref->{$_}++;
								 }
							}
						},

			},
			{
				count=>100,
				HoHoH =>sub { 	# Traverse 
							foreach my $k (keys %HoHoH) {
								 foreach my $k2 (keys %{ $HoHoH{$k} } ){
									foreach (keys %{ $HoHoH{$k}->{$k2} } ){
										$HoHoH{$k}{$k2}->{$_}++;
									}
								 }
							}
						},
				refHoHoH =>sub { # Traverse
							foreach my $k (keys %HoHoH) {
								 my $hashref = $HoHoH{$k};
								 foreach (keys %{ $hashref } ){
									my $hashref2 = $hashref->{$_};
									foreach (keys %{$hashref2} ){
										$hashref2->{$_}++;
									}
								 }
							}
						},

			},


);

foreach my $bench (@benchmarks){
	my $results = timethese(delete $bench->{count} ,$bench);
	print "-" x 20,"\n";
	cmpthese($results);
	print "-" x 40,"\n\n";
}
__END__
Benchmark: timing 10000 iterations of hash, ref...
      hash:  2 wallclock secs ( 2.06 usr +  0.00 sys =  2.06 CPU) @ 4854.37/s (n=10000)
       ref:  2 wallclock secs ( 2.18 usr +  0.00 sys =  2.18 CPU) @ 4587.16/s (n=10000)
--------------------
       Rate  ref hash
ref  4587/s   --  -6%
hash 4854/s   6%   --
----------------------------------------

Benchmark: timing 10000 iterations of ref2hash1, shortref1...
 ref2hash1:  3 wallclock secs ( 2.47 usr +  0.00 sys =  2.47 CPU) @ 4048.58/s (n=10000)
 shortref1:  3 wallclock secs ( 2.20 usr +  0.00 sys =  2.20 CPU) @ 4545.45/s (n=10000)
--------------------
            Rate ref2hash1 shortref1
ref2hash1 4049/s        --      -11%
shortref1 4545/s       12%        --
----------------------------------------

Benchmark: timing 10000 iterations of ref2hash2, shortref2...
 ref2hash2:  3 wallclock secs ( 2.90 usr +  0.00 sys =  2.90 CPU) @ 3448.28/s (n=10000)
 shortref2:  2 wallclock secs ( 2.14 usr +  0.00 sys =  2.14 CPU) @ 4672.90/s (n=10000)
--------------------
            Rate ref2hash2 shortref2
ref2hash2 3448/s        --      -26%
shortref2 4673/s       36%        --
----------------------------------------

Benchmark: timing 10000 iterations of ref2hash3, shortref3...
 ref2hash3:  3 wallclock secs ( 3.35 usr +  0.00 sys =  3.35 CPU) @ 2985.07/s (n=10000)
 shortref3:  3 wallclock secs ( 2.23 usr +  0.00 sys =  2.23 CPU) @ 4484.30/s (n=10000)
--------------------
            Rate ref2hash3 shortref3
ref2hash3 2985/s        --      -33%
shortref3 4484/s       50%        --
----------------------------------------

Benchmark: timing 10000 iterations of ref2hash4, shortref4...
 ref2hash4:  4 wallclock secs ( 3.58 usr +  0.00 sys =  3.58 CPU) @ 2793.30/s (n=10000)
 shortref4:  2 wallclock secs ( 2.16 usr +  0.00 sys =  2.16 CPU) @ 4629.63/s (n=10000)
--------------------
            Rate ref2hash4 shortref4
ref2hash4 2793/s        --      -40%
shortref4 4630/s       66%        --
----------------------------------------

Benchmark: timing 2000 iterations of HoH, refHoH...
       HoH: 16 wallclock secs (10.01 usr +  0.00 sys = 10.01 CPU) @ 199.80/s (n=2000)
    refHoH:  9 wallclock secs ( 8.98 usr +  0.00 sys =  8.98 CPU) @ 222.72/s (n=2000)
--------------------
        Rate    HoH refHoH
HoH    200/s     --   -10%
refHoH 223/s    11%     --
----------------------------------------

Benchmark: timing 100 iterations of HoHoH, refHoHoH...
     HoHoH: 30 wallclock secs (28.75 usr +  0.01 sys = 28.76 CPU) @  3.48/s (n=100)
  refHoHoH: 24 wallclock secs (22.49 usr +  0.00 sys = 22.49 CPU) @  4.45/s (n=100)
--------------------
           Rate    HoHoH refHoHoH
HoHoH    3.48/s       --     -22%
refHoHoH 4.45/s      28%       --
----------------------------------------