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lib/AI/Pathfinding/SMAstar/Path.pm  view on Meta::CPAN

#
# Representation of a path, used in the SMAstar pathfinding algorithm.
#
# Author:  matthias beebe
# Date :  June 2008
#
#

package AI::Pathfinding::SMAstar::Path;

use strict;

BEGIN {
    use Exporter ();
    @Path::ISA         = qw(Exporter);
    @Path::EXPORT      = qw();
    @Path::EXPORT_OK   = qw($d);

  }

use vars qw($d $max_forgotten_nodes);  # used to debug destroy method for accounting purposes
$d = 0;
$max_forgotten_nodes = 0;


##################################################
# Path constructor 
##################################################
sub new {
    my $invocant = shift;
    my $class   = ref($invocant) || $invocant;
    my $self = {
	
	_state                    => undef,  # node in the search space
	_eval_func               => undef,
	_goal_p_func             => undef,
	_num_successors_func     => undef,
	_successors_iterator     => undef,
	_get_data_func           => undef,

	###########################################
	#
	#   path stuff
	#
	###########################################	
	_antecedent              => undef,  # pointer to the antecedent of this obj
	_f_cost                  => undef,  # g + h where g = cost so far, h = estimated cost to goal.

	_forgotten_node_fcosts   => [],     # array to store fcosts of forgotten nodes
	_forgotten_nodes_num     => 0,

	_forgotten_nodes_offsets => {},

	_depth                   => 0,     # depth used for memory-bounded search
	_descendants_produced    => [],
	_descendant_index        => undef,	
	_descendant_fcosts       => [],
	_descendants_on_queue    => 0,

	_descendands_deleted     => 0,
	_is_completed            => 0,
	_num_successors          => undef,
	_num_successors_in_mem   => 0,
	_is_on_queue             => 0,
	_iterator_index          => 0,      # to remember index of iterator for descendants
	_need_fcost_change       => 0,      # boolean

	@_,    # attribute override
    };

    return bless $self, $class;
        
}

##############################################
# accessors
##############################################

sub state{
    my $self = shift;
    if (@_) { $self->{_state} = shift }