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

# this benchmark is a little naive, but glob is slower anyway
 
my %Subs = (
    tyeglob => sub { my $count = () = glob "*.pl*"; },
    glob => sub {
	    my $count = () =  <*.pl*>; # scalar glob returns a file, d'oh
    },
    readdir => sub {
	    opendir(DIR,'.') or die $!;
	    my $count = 0;
	    while( $_ = readdir(DIR) ) {
		    $count++ if /^.*?\.pl.*$/i;
	    }
	    closedir(DIR);
    },
    readgrep => sub {
        opendir(DIR,'.') or die $!;
	    my $count = scalar( grep {/^.*?\.pl.*/i} readdir(DIR));
        closedir(DIR);
    },
);


cmpthese( -3, \%Subs ) unless @ARGV;

if(@ARGV){ 
    print "$_ ".$Subs{$_}->()."\n" for keys %Subs;
}

__END__

Benchmark: running glob, readdir, readgrep, tyeglob, each for at least 3 CPU seconds...
      glob:  3 wallclock secs ( 3.36 usr +  0.00 sys =  3.36 CPU) @ 407.14/s (n=1368)
   readdir:  4 wallclock secs ( 3.41 usr +  0.00 sys =  3.41 CPU) @ 889.44/s (n=3033)
  readgrep:  3 wallclock secs ( 3.30 usr +  0.00 sys =  3.30 CPU) @ 1058.48/s (n=3493)
   tyeglob:  3 wallclock secs ( 3.24 usr +  0.00 sys =  3.24 CPU) @ 403.40/s (n=1307)
           Rate  tyeglob     glob  readdir readgrep
tyeglob   403/s       --      -1%     -55%     -62%
glob      407/s       1%       --     -54%     -62%
readdir   889/s     120%     118%       --     -16%
readgrep 1058/s     162%     160%      19%       --


Benchmark: running glob, readdir, readgrep, tyeglob, each for at least 3 CPU seconds...
      glob:  4 wallclock secs ( 3.07 usr +  0.00 sys =  3.07 CPU) @ 403.91/s (n=1240)
   readdir:  4 wallclock secs ( 3.57 usr +  0.00 sys =  3.57 CPU) @ 849.58/s (n=3033)
  readgrep:  4 wallclock secs ( 3.41 usr +  0.00 sys =  3.41 CPU) @ 1024.34/s (n=3493)
   tyeglob:  4 wallclock secs ( 3.30 usr +  0.00 sys =  3.30 CPU) @ 396.97/s (n=1310)
           Rate  tyeglob     glob  readdir readgrep
tyeglob   397/s       --      -2%     -53%     -61%
glob      404/s       2%       --     -52%     -61%
readdir   850/s     114%     110%       --     -17%
readgrep 1024/s     158%     154%      21%       --