#!/usr/bin/perl

# Coded by Trizen under the GPL.
# Email: echo dHJpemVueEBnbWFpbC5jb20K | base64 -d
# Website: http://trizen.go.ro
#
# This is script is just for education
#                and not for practical usage!
#
# The fastest way of doing this is of course:
#      printf '%b', 26;      # prints: 11010
#      print 0b11010;        # prints: 26
#

use bigint;
use warnings;
use strict;

my @argv_nrs;
my $verbose  = 0;
my $decoding = 0;

foreach my $arg (@ARGV) {
    if ($arg =~ /^\d+$/) {
        push @argv_nrs, $arg;
    }
    elsif (chr ord $arg eq '-') {
        if ($arg =~ /^-+h(?:elp)?$/) {
            print <<"USAGE";
Usage: $0 [option] [value|binar]\n
Options:
 -e, --encode
 -d, --decode
 -v, --verbose\n
Examples:
 $0 121
 $0 1111001 -d
USAGE
            exit;
        }
        elsif ($arg =~ /^-+v(?:erbose)?$/) {
            $verbose = 1;
        }
        elsif ($arg =~ /^-+d(?:ecode)?$/) {
            $decoding = 1;
        }
    }
}

sub decode {
    my ($code) = @_;

    return '' unless $code =~ /^[10]$/;

    my $length = length($code) - 1;

    my $binar_code = 0;
    my $nr         = 0;
    my $number     = 0;

    foreach my $i (split(//, $code, 0)) {

        $nr = $number ? ($number - 1) : $length;

        $number = $nr;
        $binar_code += $i * 2**$nr;

        if ($verbose) {
            print "$i * 2^$nr = ", $i * 2**$nr, "\n";
        }
        ++$length;
    }
    print "\n" if $verbose;
    return $binar_code;
}

sub encode {
    my ($nr) = @_;

    return '' unless $nr =~ /^\d+$/;
    return $nr if $nr < 2;

    my @encoded_array;
    my $divised = 0;

    while ($divised != 1) {

        if ($verbose) {
            print "\n$nr\t= ";
        }

        $divised = int $nr / 2;

        if ($verbose) {
            print "$divised\t * 2 \t+ (", $nr - $divised * 2, ')';
        }

        push @encoded_array, $nr - $divised * 2;
        $nr = $divised;
    }

    print "\n1\t= 0\t * 2 \t+ (1)\n" if $verbose;
    return 1 . reverse(@encoded_array);
}

sub _decode {

    if (@argv_nrs) {

        foreach my $n (@argv_nrs) {
            print decode($n) . "\n";
        }
    }
    else {
        print "=>> Decode a value:\n> ";

        foreach my $n (split(/\D+/, <STDIN>, 0)) {
            print decode($n), "\n";
        }
        exit;
    }
}

sub _encode {

    if (@argv_nrs) {

        foreach my $n (@argv_nrs) {
            print encode($n) . "\n";
        }
    }
    else {
        print "=>> Encode a value:\n> ";

        foreach my $n (split(/\D+/, <STDIN>, 0)) {
            print encode($n), "\n";
        }
        exit;
    }
}

$decoding ? _decode() : _encode();