getid3_handler::fseek

	/**
	 * @param string $string
	 */
	public function setStringMode($string) {
		$this->data_string_flag   = true;
		$this->data_string        = $string;
		$this->data_string_length = strlen($string);
	}

	/**
	 * @return int|bool
	 */
	protected function ftell() {
		if ($this->data_string_flag) {
			return $this->data_string_position;
		}
		return ftell($this->getid3->fp);
	}

	/**
	 * @param int $bytes
	 *
	 * @return string|false
	 *
	 * @throws getid3_exception
	 */
	protected function fread($bytes) {
		if ($this->data_string_flag) {