#!/usr/bin/perl

use strict;
use warnings;

use Benchmark qw(:all);

my %folders = (
    Temp1 => 10,
    Temp2 => 100,
    Temp3 => 1000,
    Temp4 => 5000,
    Temp5 => 10000,
    # Temp6 => 20000,
);

foreach my $folder (sort keys %folders) {

    print "Folder: $folder, Files: ", $folders{$folder}, "\n";

    timethese(5, {        
        'Way 1' => sub {
            opendir(my $DIR, $folder) or die "Error: couldn't open dir '$folder': $!\n";
            while(my $file = readdir $DIR) {
                my $filename = "$folder/$file";
                if(-f $filename) {
                # print STDERR "$filename\n";
                }
            }
            closedir($DIR);
        },
        'Way 2' => sub {
            foreach my $file (glob "$folder/*") {
                my $filename = $file;
                if(-f $filename) {
                #   print STDERR "$filename\n";
                }
            }
        },
        'Way 3' => sub {
            opendir(my $DIR, $folder) or die "Error: couldn't open dir '$folder': $!\n";

            my @files = map { "$folder/$_" }
                grep { -f "$folder/$_" }
                readdir($DIR);
            closedir($DIR);

            foreach my $file (@files) {
                my $filename = $file;
              #  print STDERR "$filename\n";
            }
        },
    });
}