| 453 | |
| 454 | |
| 455 | class _GzipReader(_compression.DecompressReader): |
| 456 | def __init__(self, fp): |
| 457 | super().__init__(_PaddedFile(fp), zlib.decompressobj, |
| 458 | wbits=-zlib.MAX_WBITS) |
| 459 | # Set flag indicating start of a new member |
| 460 | self._new_member = True |
| 461 | self._last_mtime = None |
| 462 | |
| 463 | def _init_read(self): |
| 464 | self._crc = zlib.crc32(b"") |
| 465 | self._stream_size = 0 # Decompressed size of unconcatenated stream |
| 466 | |
| 467 | def _read_gzip_header(self): |
| 468 | last_mtime = _read_gzip_header(self._fp) |
| 469 | if last_mtime is None: |
| 470 | return False |
| 471 | self._last_mtime = last_mtime |
| 472 | return True |
| 473 | |
| 474 | def read(self, size=-1): |
| 475 | if size < 0: |
| 476 | return self.readall() |
| 477 | # size=0 is special because decompress(max_length=0) is not supported |
| 478 | if not size: |
| 479 | return b"" |
| 480 | |
| 481 | # For certain input data, a single |
| 482 | # call to decompress() may not return |
| 483 | # any data. In this case, retry until we get some data or reach EOF. |
| 484 | while True: |
| 485 | if self._decompressor.eof: |
| 486 | # Ending case: we've come to the end of a member in the file, |
| 487 | # so finish up this member, and read a new gzip header. |
| 488 | # Check the CRC and file size, and set the flag so we read |
| 489 | # a new member |
| 490 | self._read_eof() |
| 491 | self._new_member = True |
| 492 | self._decompressor = self._decomp_factory( |
| 493 | **self._decomp_args) |
| 494 | |
| 495 | if self._new_member: |
| 496 | # If the _new_member flag is set, we have to |
| 497 | # jump to the next member, if there is one. |
| 498 | self._init_read() |
| 499 | if not self._read_gzip_header(): |
| 500 | self._size = self._pos |
| 501 | return b"" |
| 502 | self._new_member = False |
| 503 | |
| 504 | # Read a chunk of data from the file |
| 505 | buf = self._fp.read(io.DEFAULT_BUFFER_SIZE) |
| 506 | |
| 507 | uncompress = self._decompressor.decompress(buf, size) |
| 508 | if self._decompressor.unconsumed_tail != b"": |
| 509 | self._fp.prepend(self._decompressor.unconsumed_tail) |
| 510 | elif self._decompressor.unused_data != b"": |
| 511 | # Prepend the already read bytes to the fileobj so they can |
| 512 | # be seen by _read_eof() and _read_gzip_header() |