File Coverage

blib/lib/List/DoubleLinked.pm

Criterion	Covered	Total	%
statement	76	82	92.6
branch	3	8	37.5
condition			n/a
subroutine	18	19	94.7
pod	13	13	100.0
total	110	122	90.1

package List::DoubleLinked;
$List::DoubleLinked::VERSION = '0.004';
use strict;
use warnings FATAL => 'all';

use Carp qw/carp croak/;
use Scalar::Util 'weaken';
use namespace::clean 0.20;
#no autovivication;

sub new {
	my ($class, @items) = @_;
	my $self = bless {
		head => undef,
		tail => undef,
		head => { prev => undef },
		tail => { tail => undef },
	}, $class;
	$self->{head}{next} = $self->{tail};
	$self->{tail}{prev} = $self->{head};
	$self->push(@items);
	return $self;
}

## no critic (Subroutines::ProhibitBuiltinHomonyms, ControlStructures::ProhibitCStyleForLoops)

sub push {
	my ($self, @items) = @_;
	for my $item (@items) {
		my $new_tail = {
			item => $item,
			prev => $self->{tail}{prev},
			next => $self->{tail},
		};
		$self->{tail}{prev}{next} = $new_tail;
		$self->{tail}{prev} = $new_tail;
		$self->{head}{next} = $new_tail if $self->{head}{next} == $self->{tail};
	}
	return;
}

sub pop {
	my $self = shift;
	croak 'No items to pop from the list' if $self->{tail}{prev} == $self->{head};
	my $ret  = $self->{tail}{prev};
	$self->{tail}{prev} = $ret->{prev};
	$ret->{prev}{next} = $self->{tail};
	return $ret->{item};
}

sub unshift {
	my ($self, @items) = @_;
	for my $item (reverse @items) {
		my $new_head = {
			item => $item,
			prev => $self->{head},
			next => $self->{head}{next},
		};
		$self->{head}{next}{prev} = $new_head;
		$self->{head}{next} = $new_head;
	}
	return;
}

sub shift {
	my $self = CORE::shift;
	croak 'No items to shift from the list' if $self->{head}{next} == $self->{tail};
	my $ret  = $self->{head}{next};
	$self->{head}{next} = $ret->{next};
	$ret->{next}{prev} = $$self->{head};
	return $ret->{item};
}

sub flatten {
	my $self = CORE::shift;
	my @ret;
	for (my $current = $self->{head}{next} ; $current != $self->{tail}; $current = $current->{next}) {
		CORE::push @ret, $current->{item};
	}
	return @ret;
}

sub front {
	my $self = CORE::shift;
	return $self->{head}{next}{item};
}

sub back {
	my $self = CORE::shift;
	return $self->{tail}{prev}{item};
}

sub empty {
	my $self = CORE::shift;
	return $self->{head}{next} == $self->{tail}
}

sub size {
	my $self = CORE::shift;
	my $ret  = 0;
	for (my $current = $self->{head}{next} ; $current != $self->{tail}; $current = $current->{next}) {
		$ret++;
	}
	return $ret;
}

sub erase {
	my ($self, $iter) = @_;

	my $ret = $iter->next;
	my $node = $iter->[0];

	$node->{prev}{next} = $node->{next};
	$node->{next}{prev} = $node->{prev};

	weaken $node;
	carp 'Node may be leaking' if $node;

	return $ret;
}

sub begin {
	my $self = CORE::shift;
	require List::DoubleLinked::Iterator;

	return List::DoubleLinked::Iterator->new($self->{head}{next});
}

sub end {
	my $self = CORE::shift;
	require List::DoubleLinked::Iterator;

	return List::DoubleLinked::Iterator->new($self->{tail});
}

sub DESTROY {
	my $self    = CORE::shift;
	my $current = $self->{head};
	while ($current) {
		delete $current->{prev};
		$current = delete $current->{next};
	}
	return;
}

# ABSTRACT: Double Linked Lists for Perl

1;

__END__