package Search::Xapian::PositionIterator;

use 5.006;
use strict;
use warnings;
use Carp;
use Scalar::Util 'blessed';

require DynaLoader;

our @ISA = qw(DynaLoader);

# Preloaded methods go here.

# In a new thread, copy objects of this class to unblessed, undef values.
sub CLONE_SKIP { 1 }

use overload '++' => sub { $_[0]->inc() },
             '='  => sub { $_[0]->clone() },
	     'eq' => sub { $_[0]->equal($_[1]) },
	     'ne' => sub { $_[0]->nequal($_[1]) },
	     '==' => sub { $_[0]->equal($_[1]) },
	     '!=' => sub { $_[0]->nequal($_[1]) },
             '""' => sub { $_[0]->get_description() },
             '0+' => sub { $_[0]->get_termpos() },
             'fallback' => 1;

sub clone() {
  my $self = shift;
  my $class = ref( $self );
  my $copy = new2( $self );
  bless $copy, $class;
  return $copy;
}

sub equal() {
  my ($self, $other) = @_;
  if( blessed($other) && $other->isa('Search::Xapian::PositionIterator') ) {
    $self->equal1($other);
  } else {
    ($self+0) == ($other+0);
  }
}

sub nequal() {
  my ($self, $other) = @_;
  if( blessed($other) && $other->isa('Search::Xapian::PositionIterator') ) {
    $self->nequal1($other);
  } else {
    ($self+0) != ($other+0);
  }
}


sub new() {
  my $class = shift;
  my $iterator;
  my $invalid_args;
  if( scalar(@_) == 0 ) {
    $iterator = new1();
  } elsif( scalar(@_) == 1 and ref( $_[1] ) eq $class ) {
    $iterator = new2(@_);
  } else {
    $invalid_args = 1;
  }
  if( $invalid_args ) {
    Carp::carp( "USAGE: $class->new(), $class->new(\$iterator)" );
    exit;
  }
  bless $iterator, $class;
  return $iterator;
}

1;

__END__

=head1 NAME 

Search::Xapian::PositionIterator - Iterate over sets of positions.

=head1 DESCRIPTION

This iterator represents a stream of positions for a term. It overloads
C<++> for advancing the iterator, or you can explicitly call the C<inc> method.
This class also overloads C<eq>, C<ne>, C<==>, C<!=>, C<"">
(stringification) and C<0+> (conversion to an integer).

=head1 METHODS

=over 4

=item new 

Constructor. Defaults to an uninitialized iterator.

=item clone

=item inc

Advance the iterator by one. (Called implictly by C<++> overloading).

=item skip_to <termpos>

Skip the iterator to term position termpos, or the first term position after
termpos if termpos isn't in the list of term positions being iterated.

=item equal <term>

Checks if a term is the same as this term. Also overloaded to the C<eq>
and C<==> operators.

=item nequal <term>

Checks if a term is different from this term. Also overloaded to the C<ne>
and C<!=> operators.

=item get_termpos

Return the term position the iterator is currently on. Also implemented as
conversion to an integer.

=item get_description

Return a description of this object.  Also implemented as stringification.

=back

=head1 SEE ALSO

L<Search::Xapian>,L<Search::Xapian::Document>

=cut