File Coverage

blib/lib/Games/BonDigi.pm

Criterion	Covered	Total	%
statement	49	49	100.0
branch	10	10	100.0
condition	4	6	66.6
subroutine	10	10	100.0
pod	2	2	100.0
total	75	77	97.4

# $Id: BonDigi.pm 17 2008-01-13 14:23:52Z Cosimo $

package Games::BonDigi;

use strict;
use warnings;
use Carp qw(croak);

our $VERSION = '0.02';

use constant HEADER      => 0;
use constant PAYLOAD     => 1;
use constant REPEAT_WORD => 0;
use constant REPEAT_SEQ  => 1;


#
# Class constructor
#
sub new
{
    my($class) = @_;
    $class = ref($class) || $class;
    my $self = [];
    bless $self, $class;
}

#
# Build and return an iterator for the Bon-Digi-... sequence
# Every time you call it, it gives you the right word
# to be said. Hopefully.
#
# Sequence is: Bon, Digi, Bon, Digi (header)
#              Bon, Bon, Digi, Digi (payload x 2),
#              Bon, Digi, Bon, Digi (header again),
#              Bon, Bon, Bon, Digi, Digi, Digi (payload x 3),
#              Bon, Digi, Bon, Digi (header again),
#              <...> (payload x 4),
#              <...>
#              <...> (payload x n),
#
sub sequence
{
    my($self, $start, $end, @words) = @_;
    $start = 2 unless defined $start;
    $end   = 0 unless defined $end;
    @words = qw(bon digi) unless @words;

    #
    # Message structure is composed of:
    #
    # [HEADER] (fixed: "bon digi bon digi") +
    # [PAYLOAD] (grows over time: "bon bon digi digi", "bon bon bon digi digi digi")
    #
    my @repeats = (
        # This is the HEADER definition. Each word is repeated once,
        # 2 repeats of entire sequence (ex. "bon digi bon digi")
        [1, 2],

        # This is the PAYLOAD definition
        # each word is repeated '$start' times (and that keeps growing)
        # only 1 repeat of entire sequence (ex.: "bon bon digi digi")
        [$start, 1],
    );

    #
    # Define static vars for the iterator sub
    #
    my $rep  =
    my $word =
    my $i    =
    my $seq  = 0;

    my $iterator = sub
    {
        SEQUENCE: while($seq < $repeats[$rep][REPEAT_SEQ])
        {
            while($word < @words)
            {
                while($i++ < $repeats[$rep][REPEAT_WORD])
                {
                    return $words[$word];
                }
                $i = 0;
                $word++;
            }
            $seq++;
            $i = 0;
            $word = 0;
        }

        # Reinitialize sequence and restart
        $rep = 1 - $rep;
        $seq = $i = $word = 0;

        # Payload now must grow by 1
        if($rep == HEADER)
        {
            $repeats[PAYLOAD][REPEAT_WORD]++;

            # Check for sequence termination.
            # We don't want to generate more than `$end' repetitions
            # If $end == 0, sequence is unterminated
            if($end > 0 && $repeats[PAYLOAD][REPEAT_WORD] > $end)
            {
                return undef;
            }
        }

        # Yes, a GOTO here
        goto SEQUENCE;
    };

    return $iterator;
}

1;

__END__