getid3_handler::saveAttachment( string $name, int $offset, int $length, string $image_mime = null ): string|null

2435	public function saveAttachment($name, $offset, $length, $image_mime=null) {2436		$fp_dest = null;2437		$dest = null;2438		try {2439 2440			// do not extract at all2441			if ($this->getid3->option_save_attachments === getID3::ATTACHMENTS_NONE) {2442 2443				$attachment = null; // do not set any2444 2445			// extract to return array2446			} elseif ($this->getid3->option_save_attachments === getID3::ATTACHMENTS_INLINE) {2447 2448				$this->fseek($offset);2449				$attachment = $this->fread($length); // get whole data in one pass, till it is anyway stored in memory2450				if ($attachment === false || strlen($attachment) != $length) {2451					throw new Exception('failed to read attachment data');2452				}2453 2454			// assume directory path is given2455			} else {2456 2457				// set up destination path2458				$dir = rtrim(str_replace(array('/', '\\'), DIRECTORY_SEPARATOR, $this->getid3->option_save_attachments), DIRECTORY_SEPARATOR);2459				if (!is_dir($dir) || !getID3::is_writable($dir)) { // check supplied directory2460					throw new Exception('supplied path ('.$dir.') does not exist, or is not writable');2461				}2462				$dest = $dir.DIRECTORY_SEPARATOR.$name.($image_mime ? '.'.getid3_lib::ImageExtFromMime($image_mime) : '');2463 2464				// create dest file2465				if (($fp_dest = fopen($dest, 'wb')) == false) {2466					throw new Exception('failed to create file '.$dest);2467				}2468 2469				// copy data2470				$this->fseek($offset);2471				$buffersize = ($this->data_string_flag ? $length : $this->getid3->fread_buffer_size());2472				$bytesleft = $length;2473				while ($bytesleft > 0) {2474					if (($buffer = $this->fread(min($buffersize, $bytesleft))) === false || ($byteswritten = fwrite($fp_dest, $buffer)) === false || ($byteswritten === 0)) {2475						throw new Exception($buffer === false ? 'not enough data to read' : 'failed to write to destination file, may be not enough disk space');2476					}2477					$bytesleft -= $byteswritten;2478				}2479 2480				fclose($fp_dest);2481				$attachment = $dest;2482 2483			}2484 2485		} catch (Exception $e) {2486 2487			// close and remove dest file if created2488			if (isset($fp_dest) && is_resource($fp_dest)) {2489				fclose($fp_dest);2490			}2491 2492			if (isset($dest) && file_exists($dest)) {2493				unlink($dest);2494			}2495 2496			// do not set any is case of error2497			$attachment = null;2498			$this->warning('Failed to extract attachment '.$name.': '.$e->getMessage());2499 2500		}2501 2502		// seek to the end of attachment2503		$this->fseek($offset + $length);2504 2505		return $attachment;2506	}