diff options
Diffstat (limited to 'Lib/gzip.py')
| -rw-r--r-- | Lib/gzip.py | 105 |
1 files changed, 77 insertions, 28 deletions
diff --git a/Lib/gzip.py b/Lib/gzip.py index ee45e50..b6656a9 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -16,17 +16,49 @@ FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16 READ, WRITE = 1, 2 -def U32(i): - """Return i as an unsigned integer, assuming it fits in 32 bits. - If it's >= 2GB when viewed as a 32-bit unsigned int, return a long. - """ - if i < 0: - i += 1 << 32 - return i +def open(filename, mode="rb", compresslevel=9, + encoding=None, errors=None, newline=None): + """Open a gzip-compressed file in binary or text mode. + + The filename argument can be an actual filename (a str or bytes object), or + an existing file object to read from or write to. + + The mode argument can be "r", "rb", "w", "wb", "a" or "ab" for binary mode, + or "rt", "wt" or "at" for text mode. The default mode is "rb", and the + default compresslevel is 9. -def LOWU32(i): - """Return the low-order 32 bits, as a non-negative int""" - return i & 0xFFFFFFFF + For binary mode, this function is equivalent to the GzipFile constructor: + GzipFile(filename, mode, compresslevel). In this case, the encoding, errors + and newline arguments must not be provided. + + For text mode, a GzipFile object is created, and wrapped in an + io.TextIOWrapper instance with the specified encoding, error handling + behavior, and line ending(s). + + """ + if "t" in mode: + if "b" in mode: + raise ValueError("Invalid mode: %r" % (mode,)) + else: + if encoding is not None: + raise ValueError("Argument 'encoding' not supported in binary mode") + if errors is not None: + raise ValueError("Argument 'errors' not supported in binary mode") + if newline is not None: + raise ValueError("Argument 'newline' not supported in binary mode") + + gz_mode = mode.replace("t", "") + if isinstance(filename, (str, bytes)): + binary_file = GzipFile(filename, gz_mode, compresslevel) + elif hasattr(filename, "read") or hasattr(filename, "write"): + binary_file = GzipFile(None, gz_mode, compresslevel, filename) + else: + raise TypeError("filename must be a str or bytes object, or a file") + + if "t" in mode: + return io.TextIOWrapper(binary_file, encoding, errors, newline) + else: + return binary_file def write32u(output, value): # The L format writes the bit pattern correctly whether signed @@ -36,15 +68,6 @@ def write32u(output, value): def read32(input): return struct.unpack("<I", input.read(4))[0] -def open(filename, mode="rb", compresslevel=9): - """Shorthand for GzipFile(filename, mode, compresslevel). - - The filename argument is required; mode defaults to 'rb' - and compresslevel defaults to 9. - - """ - return GzipFile(filename, mode, compresslevel) - class _PaddedFile: """Minimal read-only file object that prepends a string to the contents of an actual file. Shouldn't be used outside of gzip.py, as it lacks @@ -106,7 +129,7 @@ class GzipFile(io.BufferedIOBase): the exception of the readinto() and truncate() methods. This class only supports opening files in binary mode. If you need to open a - compressed file in text mode, wrap your GzipFile with an io.TextIOWrapper. + compressed file in text mode, use the gzip.open() function. """ @@ -153,7 +176,7 @@ class GzipFile(io.BufferedIOBase): """ if mode and ('t' in mode or 'U' in mode): - raise IOError("Mode " + mode + " not supported") + raise ValueError("Invalid mode: {!r}".format(mode)) if mode and 'b' not in mode: mode += 'b' if fileobj is None: @@ -163,10 +186,9 @@ class GzipFile(io.BufferedIOBase): if not isinstance(filename, (str, bytes)): filename = '' if mode is None: - if hasattr(fileobj, 'mode'): mode = fileobj.mode - else: mode = 'rb' + mode = getattr(fileobj, 'mode', 'rb') - if mode[0:1] == 'r': + if mode.startswith('r'): self.mode = READ # Set flag indicating start of a new member self._new_member = True @@ -181,7 +203,7 @@ class GzipFile(io.BufferedIOBase): self.min_readsize = 100 fileobj = _PaddedFile(fileobj) - elif mode[0:1] == 'w' or mode[0:1] == 'a': + elif mode.startswith(('w', 'a')): self.mode = WRITE self._init_write(filename) self.compress = zlib.compressobj(compresslevel, @@ -190,7 +212,7 @@ class GzipFile(io.BufferedIOBase): zlib.DEF_MEM_LEVEL, 0) else: - raise IOError("Mode " + mode + " not supported") + raise ValueError("Invalid mode: {!r}".format(mode)) self.fileobj = fileobj self.offset = 0 @@ -353,6 +375,31 @@ class GzipFile(io.BufferedIOBase): self.offset += size return chunk + def read1(self, size=-1): + self._check_closed() + if self.mode != READ: + import errno + raise IOError(errno.EBADF, "read1() on write-only GzipFile object") + + if self.extrasize <= 0 and self.fileobj is None: + return b'' + + try: + # For certain input data, a single call to _read() may not return + # any data. In this case, retry until we get some data or reach EOF. + while self.extrasize <= 0: + self._read() + except EOFError: + pass + if size < 0 or size > self.extrasize: + size = self.extrasize + + offset = self.offset - self.extrastart + chunk = self.extrabuf[offset: offset + size] + self.extrasize -= size + self.offset += size + return chunk + def peek(self, n): if self.mode != READ: import errno @@ -366,8 +413,10 @@ class GzipFile(io.BufferedIOBase): if self.fileobj is None: return b'' try: - # 1024 is the same buffering heuristic used in read() - self._read(max(n, 1024)) + # Ensure that we don't return b"" if we haven't reached EOF. + while self.extrasize == 0: + # 1024 is the same buffering heuristic used in read() + self._read(max(n, 1024)) except EOFError: pass offset = self.offset - self.extrastart |