#!/usr/bin/perl -w

use strict;
use Benchmark qw(cmpthese);

my $file = $0;
open(IN, $file) or die "$file: $!\n";

cmpthese(50_000, {
    join     => \&_join,
    linesep  => \&_linesep,
    hybrid   => \&_hybrid,
    sysread  => \&_sysread,
    argv     => \&_argv
});

close(IN);

sub _join { 
    seek(IN, 0, 0); my $content = join '', <IN>; 
}

sub _linesep { 
    seek(IN, 0, 0); my $content = do { local $/; <IN> } 
}

sub _hybrid { 
    seek(IN, 0, 0); my $content = do { local $/; join '', <IN> } 
}

sub _sysread { 
    seek(IN, 0, 0); sysread IN, my $content, -s IN 
}

sub _argv { 
    my $content = 
        do { local(*ARGV, $/); @ARGV = ($file); <> } 
}