File Coverage

blib/lib/Games/LMSolve/Numbers.pm

Criterion	Covered	Total	%
statement	12	92	13.0
branch	0	20	0.0
condition			n/a
subroutine	4	13	30.7
pod	7	7	100.0
total	23	132	17.4

package Games::LMSolve::Numbers;
$Games::LMSolve::Numbers::VERSION = '0.14.0';
use strict;
use warnings;

use Games::LMSolve::Base;

use vars qw(@ISA);

@ISA = qw(Games::LMSolve::Base);

my %cell_dirs = (
    'N' => [ 0,  -1 ],
    'S' => [ 0,  1 ],
    'E' => [ 1,  0 ],
    'W' => [ -1, 0 ],
);

sub input_board
{
    my $self = shift;

    my $filename = shift;

    my $spec = {
        'dims'   => { 'type' => "xy(integer)", 'required' => 1 },
        'start'  => { 'type' => "xy(integer)", 'required' => 1 },
        'layout' => { 'type' => "layout",      'required' => 1 },
    };

    my $input_obj    = Games::LMSolve::Input->new();
    my $input_fields = $input_obj->input_board( $filename, $spec );
    my ( $width, $height ) =
        @{ $input_fields->{'dims'}->{'value'} }{ 'x', 'y' };
    my ( $start_x, $start_y ) =
        @{ $input_fields->{'start'}->{'value'} }{ 'x', 'y' };
    my (@board);

    my $line;
    my $line_number = 0;
    my $lines_ref   = $input_fields->{'layout'}->{'value'};

    my $read_line = sub {
        if ( scalar(@$lines_ref) == $line_number )
        {
            return 0;
        }
        $line = $lines_ref->[$line_number];
        $line_number++;
        return 1;
    };

    my $gen_exception = sub {
        my $text = shift;
        die "$text on $filename at line "
            . ( $input_fields->{'layout'}->{'line_num'} + $line_number + 1 )
            . "!\n";
    };

    my $y = 0;

INPUT_LOOP: while ( $read_line->() )
    {
        if ( length($line) != $width )
        {
            $gen_exception->("Incorrect number of cells");
        }
        if ( $line =~ /([^\d\*])/ )
        {
            $gen_exception->("Unknown cell type $1");
        }
        push @board, [ split( //, $line ) ];
        $y++;
        if ( $y == $height )
        {
            last;
        }
    }

    if ( $y != $height )
    {
        $gen_exception->("Input terminated prematurely after reading $y lines");
    }

    if ( !defined($start_x) )
    {
        $gen_exception->("The starting position was not defined anywhere");
    }

    $self->{'height'} = $height;
    $self->{'width'}  = $width;
    $self->{'board'}  = \@board;

    return [ $start_x, $start_y ];
}

# A function that accepts the expanded state (as an array ref)
# and returns an atom that represents it.
sub pack_state
{
    my $self         = shift;
    my $state_vector = shift;
    return pack( "cc", @{$state_vector} );
}

# A function that accepts an atom that represents a state
# and returns an array ref that represents it.
sub unpack_state
{
    my $self  = shift;
    my $state = shift;
    return [ unpack( "cc", $state ) ];
}

# Accept an atom that represents a state and output a
# user-readable string that describes it.
sub display_state
{
    my $self  = shift;
    my $state = shift;
    my ( $x, $y ) = @{ $self->unpack_state($state) };
    return sprintf( "X = %i ; Y = %i", $x + 1, $y + 1 );
}

sub check_if_final_state
{
    my $self = shift;

    my $coords = shift;
    return $self->{'board'}->[ $coords->[1] ][ $coords->[0] ] eq "*";
}

# This function enumerates the moves accessible to the state.
# If it returns a move, it still does not mean that it is a valid
# one. I.e: it is possible that it is illegal to perform it.
sub enumerate_moves
{
    my $self = shift;

    my $coords = shift;

    my $x = $coords->[0];
    my $y = $coords->[1];

    my $step = $self->{'board'}->[$y][$x];

    my @moves;

    if ( $x + $step < $self->{'width'} )
    {
        push @moves, "E";
    }

    # The ranges are [0 .. ($width-1)] and [0 .. ($height-1)]
    if ( $x - $step >= 0 )
    {
        push @moves, "W";
    }

    if ( $y + $step < $self->{'height'} )
    {
        push @moves, "S";
    }

    if ( $y - $step >= 0 )
    {
        push @moves, "N";
    }

    return @moves;
}

# This function accepts a state and a move. It tries to perform the
# move on the state. If it is succesful, it returns the new state.
#
# Else, it returns undef to indicate that the move is not possible.
sub perform_move
{
    my $self = shift;

    my $coords = shift;
    my $m      = shift;

    my $step = $self->{'board'}->[ $coords->[1] ][ $coords->[0] ];

    my $offsets    = [ map { $_ * $step } @{ $cell_dirs{$m} } ];
    my @new_coords = @$coords;
    $new_coords[0] += $offsets->[0];
    $new_coords[1] += $offsets->[1];

    return [@new_coords];
}

1;

__END__