=head1 NAME

RocksDB::Iterator - rocksdb::Iterator object

=head1 SYNOPSIS

  use RocksDB;

  my $db = RocksDB->new('/path/to/db');
  my $iter = $db->new_iterator->seek_to_first;
  while (my ($key, $value) = $iter->each) {
      printf "%s: %s\n", $key, $value;
  }
  # in reverse order
  $iter->seek_to_last;
  while (my ($key, $value) = $iter->reverse_each) {
      printf "%s: %s\n", $key, $value;
  }

  # low-level interface
  for ($iter->seek_to_first; $iter->valid; $iter->next) {
      printf "%s: %s\n", $iter->key, $iter->value;
  }
  for ($iter->seek_to_last; $iter->valid; $iter->prev) {
      printf "%s: %s\n", $iter->key, $iter->value;
  }
  $iter->seek('key');

=head1 DESCRIPTION

B<RocksDB::Iterator> is a rocksdb::Iterator object.

=head1 METHODS

=head2 C<< $iter->valid() :Bool >>

An iterator is either positioned at a key/value pair, or
not valid.  This method returns true iff the iterator is valid.

=head2 C<< $iter->seek_to_first() :LevelDB::Iterator >>

Position at the first key in the source.  The iterator is valid()
after this call iff the source is not empty.
Return $self. It's useful for method chain as below.

  my $iter = $db->new_iterator->seek_to_first;

=head2 C<< $iter->seek_to_last() :LevelDB::Iterator >>

Position at the last key in the source.  The iterator is
valid() after this call iff the source is not empty.

=head2 C<< $iter->seek($key :Str) :RocksDB::Iterator >>

Position at the first key in the source that at or past target
The iterator is valid() after this call iff the source contains
an entry that comes at or past target.

=head2 C<< $iter->next() :Undef >>

Moves to the next entry in the source.  After this call, valid() is
true iff the iterator was not positioned at the last entry in the source.
Raise error if the iterator is not valid().

=head2 C<< $iter->prev() :Undef >>

Moves to the previous entry in the source.  After this call, Valid() is
true iff the iterator was not positioned at the first entry in source.
Raise error if the iterator is not valid().

=head2 C<< $iter->key() :Str >>

Return the key for the current entry.  The underlying storage for
the returned slice is valid only until the next modification of
the iterator.
Return undef if the iterator is not valid().

=head2 C<< $iter->value() :Str >>

Return the value for the current entry.  The underlying storage for
the returned slice is valid only until the next modification of
the iterator.
Return undef if the iterator is not valid().

=head2 C<< $iter->each() :(Str, Str) >>

If the iterator is valid(), return key-value pair and call next().
Otherwise return empty list.

=head2 C<< $iter->reverse_each() :(Str, Str) >>

If the iterator is valid(), return key-value pair and call prev().
Otherwise return empty list.

=head1 SEE ALSO

L<RocksDB>

=head1 AUTHOR

Jiro Nishiguchi E<lt>jiro@cpan.orgE<gt>

=cut