#!/usr/bin/env perl
use warnings;
use strict;
use Benchmark 'cmpthese';

my $lookup = join '', map{ chr( $_ / 255 * 100 ) } 0 .. 255;
my $const = 100 / 255;

cmpthese(-2, {
	lookup => sub {
        my @output = map { ord( substr $lookup, $_, 1 )} 0 .. 255;
	},
	calc   => sub {
        my @output = map {$_ / 255 * 100} 0 .. 255;
	},
	calc2   => sub {
        my @output = map {$_ * $const} 0 .. 255;
	},
});

my @output1 = map { ord( substr $lookup, $_, 1 )} 0 .. 5;
my @output2 = map {$_ * $const} 0 .. 5;
print "@output1\n";
print "@output2\n";
__END__

# Results on my machine (v5.22.1 built for MSWin32-x64-multi-thread):
          Rate   calc  calc2 lookup
calc   12009/s     --   -24%   -31%
calc2  15753/s    31%     --    -9%
lookup 17376/s    45%    10%     --
0 0 0 1 1 1
0 0.392156862745098 0.784313725490196 1.17647058823529 1.56862745098039 1.96078431372549