getid3_lib::hash_data( string $file, int $offset, int $end, string $algorithm ): string|false

788	public static function hash_data($file, $offset, $end, $algorithm) {789		if (!self::intValueSupported($end)) {790			return false;791		}792		if (!in_array($algorithm, array('md5', 'sha1'))) {793			throw new getid3_exception('Invalid algorithm ('.$algorithm.') in self::hash_data()');794		}795 796		$size = $end - $offset;797 798		$fp = fopen($file, 'rb');799		fseek($fp, $offset);800		$ctx = hash_init($algorithm);801		while ($size > 0) {802			$buffer = fread($fp, min($size, getID3::FREAD_BUFFER_SIZE));803			hash_update($ctx, $buffer);804			$size -= getID3::FREAD_BUFFER_SIZE;805		}806		$hash = hash_final($ctx);807		fclose($fp);808 809		return $hash;810	}