decode_nw-7.pl

#!/usr/bin/env perl

use strict;
use warnings;

# usage:
# $ perl decode_nw-7.pl 12121121211112111121121112111121122111111212112
# -> B5468B

my %characters = (
	'1111122' => '0',
	'1111221' => '1',
	'1112112' => '2',
	'2211111' => '3',
	'1121121' => '4',
	'2111121' => '5',
	'1211112' => '6',
	'1211211' => '7',
	'1221111' => '8',
	'2112111' => '9',
	'1112211' => '-',
	'1122111' => '$',
	'2111212' => ':',
	'2121112' => '/',
	'2121211' => '.',
	'1121212' => '+',
	'1122121' => 'A',
	'1212112' => 'B',
	'1112122' => 'C',
	'1112221' => 'D',
);

my $input = $ARGV[0];

my $buf = "";
my $separator_flag = 0;
foreach (split //, $input) {
	if ($separator_flag == 1) {
		die "decode error: not found separator" if $_ ne "1";
		$separator_flag = 0;
		next;
	}
	$buf .= $_;
	if (length($buf) == 7) {
		if (!exists($characters{$buf})) {
			die "decode error: not exist character";
		}
		print $characters{$buf};
		$buf = "";
		$separator_flag = 1;
	}
}
if (length($buf) > 0) {
	die "decode error: broken code";
}
print "\n";