#!perl -w
use strict;
use 5.010;
use Benchmark qw(:all);
use File::Map 'map_file';

my $testfile= "$0.testdata";
my $data= '0123456789' x 20e6;

# Create the test file. This likely means that it is still hot in the cache...
open my $fh, '>', $testfile
    or die "Couldn't create '$testfile': $!";
print {$fh} $data;
undef $fh;

sub tr_in_memory {
    (my $fn)= @_;
    my $count= ($data =~ tr[0][0]);
    $count
};

sub tr_map_file {
    (my $fn)= @_;
    map_file my($content), $testfile;
    my $count= ($content =~ tr[0][0]);
    $count
};

sub tr_via_readline_10_000 {
    my $total_filtered = 0;
    open my $cgs, "<", $testfile;
    local $/ = \10_000; # blocksize
    $total_filtered += tr/0/0/ while <$cgs>;
};

sub tr_via_readline_100_000 {
    my $total_filtered = 0;
    open my $cgs, "<", $testfile;
    local $/ = \100_000; # blocksize
    $total_filtered += tr/0/0/ while <$cgs>;
};

sub tr_via_readline_1_000_000 {
    my $total_filtered = 0;
    open my $cgs, "<", $testfile;
    local $/ = \1_000_000; # blocksize
    $total_filtered += tr/0/0/ while <$cgs>;
};

say sprintf "Running with a dataset of %d", length $data;
cmpthese( 30, {
    'tr_map_file' => \&tr_map_file,
    'tr_in_memory' => \&tr_in_memory,
    'tr_via_readline 10k' => \&tr_via_readline_10_000,
    'tr_via_readline 100k' => \&tr_via_readline_100_000,
    'tr_via_readline 1m' => \&tr_via_readline_1_000_000,
}
);