#!/usr/bin/perl
use strict;
use warnings;
# use Benchmark qw(:all) ; # WindowsOS
use Benchmark::Forking qw( timethese cmpthese ); # UnixOS

my @preserved = @ARGV;

sub while_test {
    my %data_hash   = ();
    my %output_hash = ();

    @ARGV = @preserved; # restore original @ARGV

    while (<>) {                          # Build list of unique (site:dsk) items
	my ($site, $buf) = split(/,/);

	my @input_item = split(/:/, $buf);
	while ( defined ( my $input_field = shift @input_item ) ) { # EX: "VAR8=36!206!207!"
	    my @dsk_list = ($input_field =~ /([0-9]+)!([0-9]+)!$/);  # Get last 2 of 3 items

	    while ( defined ( my $dsk = shift @dsk_list ) ) { # Each dsk item in the input...
		next if ($dsk == 0);              # Skip '0' dsk items
		my $key = $site . ":" . $dsk;        # Build composite key
		$data_hash{$key}++;               # ...and save it
	    }
	}
    }

    my @sort_data_keys = sort keys %data_hash;
    while ( defined ( my $key = shift (@sort_data_keys) ) ) { # Build list of dsk -> (multi sites)
	my ($site, $dsk) = split(/:/, $key);
	push( @{$output_hash{$dsk} }, $site );
    }

    my @sort_output_hash = sort {$a <=> $b} keys %output_hash;
    while ( defined ( my $dsk = shift (@sort_output_hash) ) ) { # Show list of sites for each dsk
	# printf("Dsk: %d:\n", $dsk);
	foreach my $site (sort {$a <=> $b} @{$output_hash{$dsk}}) {
	    # printf("  %d\n", $site);
	}
	# printf("\n");
    }
}

sub foreach_test {
    my %data_hash   = ();
    my %output_hash = ();

    @ARGV = @preserved; # restore original @ARGV

    while(<>) {                          # Build list of unique (site:dsk) items
	my ($site, $buf) = split(/,/);

	my @input_item = split(/:/, $buf);
	foreach my $input_field (@input_item) {    # EX: "VAR8=36!206!207!"
	    my @dsk_list = ($input_field =~ /([0-9]+)!([0-9]+)!$/);  # Get last 2 of 3 items

	    foreach my $dsk (@dsk_list) {           # Each dsk item in the input...
		next if ($dsk == 0);              # Skip '0' dsk items
		my $key = $site . ":" . $dsk;        # Build composite key
		$data_hash{$key}++;               # ...and save it
	    }
	}
    }

    foreach my $key ( sort keys %data_hash ) {    # Build list of dsk -> (multi sites)
	my ($site, $dsk) = split(/:/, $key);
	push( @{$output_hash{$dsk} }, $site );
    }

    foreach my $dsk (sort {$a <=> $b} keys %output_hash) {  # Show list of sites for each dsk
	# printf("Dsk: %d:\n", $dsk);
	foreach my $site (sort {$a <=> $b} @{$output_hash{$dsk}}) {
	    # printf("  %d\n", $site);
	}
	# printf("\n");
    }
}

my $results = timethese(1000000, { While => \&while_test,
				   ForEach => \&foreach_test, }, 'none');
cmpthese( $results );

__END__

$ perl test.pl in.txt
           Rate   While ForEach
While   14286/s      --    -10%
ForEach 15898/s     11%      --