public function _geoip_seek_country_v6( $ipnum ) {
		// arrays from unpack start with offset 1
		// yet another php mystery. array_merge work around
		// this broken behaviour
		$v6vec = array_merge( unpack( 'C16', $ipnum ) );

		$offset = 0;
		for ( $depth = 127; $depth >= 0; --$depth ) {
			if ( $this->flags & self::GEOIP_MEMORY_CACHE ) {
				$buf = $this->_safe_substr(
					$this->memory_buffer,
					2 * $this->record_length * $offset,
					2 * $this->record_length
				);
			} elseif ( $this->flags & self::GEOIP_SHARED_MEMORY ) {
				$buf = @shmop_read(
					$this->shmid,
					2 * $this->record_length * $offset,
					2 * $this->record_length
				);
			} else {
				if ( 0 != fseek( $this->filehandle, 2 * $this->record_length * $offset, SEEK_SET ) ) {
					break;
				}

				$buf = fread( $this->filehandle, 2 * $this->record_length );
			}
			$x = array( 0, 0 );
			for ( $i = 0; $i < 2; ++$i ) {
				for ( $j = 0; $j < $this->record_length; ++$j ) {
					$x[ $i ] += ord( $buf[ $this->record_length * $i + $j ] ) << ( $j * 8 );
				}
			}

			$bnum = 127 - $depth;
			$idx = $bnum >> 3;
			$b_mask = 1 << ( $bnum & 7 ^ 7 );
			if ( ( $v6vec[ $idx ] & $b_mask ) > 0 ) {
				if ( $x[1] >= $this->databaseSegments ) {
					return $x[1];
				}
				$offset = $x[1];
			} else {
				if ( $x[0] >= $this->databaseSegments ) {
					return $x[0];
				}
				$offset = $x[0];
			}
		}

		$this->log( 'GeoIP API: Error traversing database - perhaps it is corrupt?', 'error' );

		return false;
	}