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			674 lines
		
	
	
	
		
			24 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			674 lines
		
	
	
	
		
			24 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""Functions that read and write gzipped files.
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The user of the file doesn't have to worry about the compression,
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but random access is not allowed."""
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# based on Andrew Kuchling's minigzip.py distributed with the zlib module
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import struct, sys, time, os
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import zlib
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import builtins
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import io
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__all__ = ["GzipFile", "open", "compress", "decompress"]
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FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16
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READ, WRITE = 1, 2
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def open(filename, mode="rb", compresslevel=9,
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         encoding=None, errors=None, newline=None):
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    """Open a gzip-compressed file in binary or text mode.
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    The filename argument can be an actual filename (a str or bytes object), or
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    an existing file object to read from or write to.
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    The mode argument can be "r", "rb", "w", "wb", "a" or "ab" for binary mode,
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    or "rt", "wt" or "at" for text mode. The default mode is "rb", and the
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    default compresslevel is 9.
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    For binary mode, this function is equivalent to the GzipFile constructor:
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    GzipFile(filename, mode, compresslevel). In this case, the encoding, errors
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    and newline arguments must not be provided.
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    For text mode, a GzipFile object is created, and wrapped in an
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    io.TextIOWrapper instance with the specified encoding, error handling
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    behavior, and line ending(s).
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    """
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    if "t" in mode:
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        if "b" in mode:
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            raise ValueError("Invalid mode: %r" % (mode,))
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    else:
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        if encoding is not None:
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            raise ValueError("Argument 'encoding' not supported in binary mode")
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        if errors is not None:
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            raise ValueError("Argument 'errors' not supported in binary mode")
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        if newline is not None:
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            raise ValueError("Argument 'newline' not supported in binary mode")
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    gz_mode = mode.replace("t", "")
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    if isinstance(filename, (str, bytes)):
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        binary_file = GzipFile(filename, gz_mode, compresslevel)
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    elif hasattr(filename, "read") or hasattr(filename, "write"):
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        binary_file = GzipFile(None, gz_mode, compresslevel, filename)
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    else:
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        raise TypeError("filename must be a str or bytes object, or a file")
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    if "t" in mode:
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        return io.TextIOWrapper(binary_file, encoding, errors, newline)
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    else:
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        return binary_file
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def write32u(output, value):
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    # The L format writes the bit pattern correctly whether signed
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    # or unsigned.
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    output.write(struct.pack("<L", value))
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class _PaddedFile:
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    """Minimal read-only file object that prepends a string to the contents
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    of an actual file. Shouldn't be used outside of gzip.py, as it lacks
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    essential functionality."""
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    def __init__(self, f, prepend=b''):
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        self._buffer = prepend
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        self._length = len(prepend)
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        self.file = f
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        self._read = 0
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    def read(self, size):
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        if self._read is None:
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            return self.file.read(size)
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        if self._read + size <= self._length:
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            read = self._read
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            self._read += size
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            return self._buffer[read:self._read]
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        else:
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            read = self._read
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            self._read = None
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            return self._buffer[read:] + \
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                   self.file.read(size-self._length+read)
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    def prepend(self, prepend=b'', readprevious=False):
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        if self._read is None:
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            self._buffer = prepend
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        elif readprevious and len(prepend) <= self._read:
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            self._read -= len(prepend)
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            return
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        else:
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            self._buffer = self._buffer[read:] + prepend
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        self._length = len(self._buffer)
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        self._read = 0
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    def unused(self):
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        if self._read is None:
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            return b''
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        return self._buffer[self._read:]
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    def seek(self, offset, whence=0):
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        # This is only ever called with offset=whence=0
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        if whence == 1 and self._read is not None:
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            if 0 <= offset + self._read <= self._length:
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                self._read += offset
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                return
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            else:
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                offset += self._length - self._read
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        self._read = None
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        self._buffer = None
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        return self.file.seek(offset, whence)
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    def __getattr__(self, name):
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        return getattr(self.file, name)
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class GzipFile(io.BufferedIOBase):
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    """The GzipFile class simulates most of the methods of a file object with
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    the exception of the readinto() and truncate() methods.
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    This class only supports opening files in binary mode. If you need to open a
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    compressed file in text mode, use the gzip.open() function.
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    """
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    myfileobj = None
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    max_read_chunk = 10 * 1024 * 1024   # 10Mb
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    def __init__(self, filename=None, mode=None,
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                 compresslevel=9, fileobj=None, mtime=None):
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        """Constructor for the GzipFile class.
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        At least one of fileobj and filename must be given a
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        non-trivial value.
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        The new class instance is based on fileobj, which can be a regular
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        file, a StringIO object, or any other object which simulates a file.
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        It defaults to None, in which case filename is opened to provide
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        a file object.
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        When fileobj is not None, the filename argument is only used to be
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        included in the gzip file header, which may includes the original
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        filename of the uncompressed file.  It defaults to the filename of
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        fileobj, if discernible; otherwise, it defaults to the empty string,
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        and in this case the original filename is not included in the header.
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        The mode argument can be any of 'r', 'rb', 'a', 'ab', 'w', or 'wb',
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        depending on whether the file will be read or written.  The default
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        is the mode of fileobj if discernible; otherwise, the default is 'rb'.
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        A mode of 'r' is equivalent to one of 'rb', and similarly for 'w' and
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        'wb', and 'a' and 'ab'.
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        The compresslevel argument is an integer from 0 to 9 controlling the
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        level of compression; 1 is fastest and produces the least compression,
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        and 9 is slowest and produces the most compression. 0 is no compression
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        at all. The default is 9.
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        The mtime argument is an optional numeric timestamp to be written
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        to the stream when compressing.  All gzip compressed streams
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        are required to contain a timestamp.  If omitted or None, the
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        current time is used.  This module ignores the timestamp when
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        decompressing; however, some programs, such as gunzip, make use
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        of it.  The format of the timestamp is the same as that of the
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        return value of time.time() and of the st_mtime member of the
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        object returned by os.stat().
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        """
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        if mode and ('t' in mode or 'U' in mode):
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            raise ValueError("Invalid mode: {!r}".format(mode))
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        if mode and 'b' not in mode:
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            mode += 'b'
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        if fileobj is None:
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            fileobj = self.myfileobj = builtins.open(filename, mode or 'rb')
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        if filename is None:
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            filename = getattr(fileobj, 'name', '')
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            if not isinstance(filename, (str, bytes)):
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                filename = ''
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        if mode is None:
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            mode = getattr(fileobj, 'mode', 'rb')
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        if mode.startswith('r'):
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            self.mode = READ
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            # Set flag indicating start of a new member
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            self._new_member = True
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            # Buffer data read from gzip file. extrastart is offset in
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            # stream where buffer starts. extrasize is number of
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            # bytes remaining in buffer from current stream position.
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            self.extrabuf = b""
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            self.extrasize = 0
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            self.extrastart = 0
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            self.name = filename
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            # Starts small, scales exponentially
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            self.min_readsize = 100
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            fileobj = _PaddedFile(fileobj)
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        elif mode.startswith(('w', 'a')):
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            self.mode = WRITE
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            self._init_write(filename)
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            self.compress = zlib.compressobj(compresslevel,
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                                             zlib.DEFLATED,
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                                             -zlib.MAX_WBITS,
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                                             zlib.DEF_MEM_LEVEL,
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                                             0)
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        else:
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            raise ValueError("Invalid mode: {!r}".format(mode))
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        self.fileobj = fileobj
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        self.offset = 0
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        self.mtime = mtime
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        if self.mode == WRITE:
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            self._write_gzip_header()
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    @property
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    def filename(self):
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        import warnings
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        warnings.warn("use the name attribute", DeprecationWarning, 2)
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        if self.mode == WRITE and self.name[-3:] != ".gz":
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            return self.name + ".gz"
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        return self.name
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    def __repr__(self):
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        fileobj = self.fileobj
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        if isinstance(fileobj, _PaddedFile):
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            fileobj = fileobj.file
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        s = repr(fileobj)
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        return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>'
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    def _check_closed(self):
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        """Raises a ValueError if the underlying file object has been closed.
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        """
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        if self.closed:
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            raise ValueError('I/O operation on closed file.')
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    def _init_write(self, filename):
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        self.name = filename
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        self.crc = zlib.crc32(b"") & 0xffffffff
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        self.size = 0
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        self.writebuf = []
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        self.bufsize = 0
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    def _write_gzip_header(self):
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        self.fileobj.write(b'\037\213')             # magic header
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        self.fileobj.write(b'\010')                 # compression method
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        try:
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            # RFC 1952 requires the FNAME field to be Latin-1. Do not
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            # include filenames that cannot be represented that way.
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            fname = os.path.basename(self.name)
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            if not isinstance(fname, bytes):
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                fname = fname.encode('latin-1')
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            if fname.endswith(b'.gz'):
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                fname = fname[:-3]
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        except UnicodeEncodeError:
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            fname = b''
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        flags = 0
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        if fname:
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            flags = FNAME
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        self.fileobj.write(chr(flags).encode('latin-1'))
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        mtime = self.mtime
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        if mtime is None:
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            mtime = time.time()
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        write32u(self.fileobj, int(mtime))
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        self.fileobj.write(b'\002')
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        self.fileobj.write(b'\377')
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        if fname:
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            self.fileobj.write(fname + b'\000')
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    def _init_read(self):
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        self.crc = zlib.crc32(b"") & 0xffffffff
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        self.size = 0
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    def _read_exact(self, n):
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        data = self.fileobj.read(n)
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        while len(data) < n:
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            b = self.fileobj.read(n - len(data))
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            if not b:
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                raise EOFError("Compressed file ended before the "
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                               "end-of-stream marker was reached")
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            data += b
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        return data
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    def _read_gzip_header(self):
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        magic = self.fileobj.read(2)
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        if magic == b'':
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            return False
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        if magic != b'\037\213':
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            raise OSError('Not a gzipped file')
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        method, flag, self.mtime = struct.unpack("<BBIxx", self._read_exact(8))
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        if method != 8:
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            raise OSError('Unknown compression method')
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        if flag & FEXTRA:
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            # Read & discard the extra field, if present
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            extra_len, = struct.unpack("<H", self._read_exact(2))
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            self._read_exact(extra_len)
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        if flag & FNAME:
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            # Read and discard a null-terminated string containing the filename
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            while True:
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                s = self.fileobj.read(1)
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                if not s or s==b'\000':
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                    break
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        if flag & FCOMMENT:
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            # Read and discard a null-terminated string containing a comment
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            while True:
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                s = self.fileobj.read(1)
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                if not s or s==b'\000':
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                    break
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        if flag & FHCRC:
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            self._read_exact(2)     # Read & discard the 16-bit header CRC
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        unused = self.fileobj.unused()
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        if unused:
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            uncompress = self.decompress.decompress(unused)
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            self._add_read_data(uncompress)
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        return True
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    def write(self,data):
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        self._check_closed()
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        if self.mode != WRITE:
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            import errno
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            raise OSError(errno.EBADF, "write() on read-only GzipFile object")
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        if self.fileobj is None:
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            raise ValueError("write() on closed GzipFile object")
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        # Convert data type if called by io.BufferedWriter.
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        if isinstance(data, memoryview):
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            data = data.tobytes()
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        if len(data) > 0:
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            self.size = self.size + len(data)
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            self.crc = zlib.crc32(data, self.crc) & 0xffffffff
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            self.fileobj.write( self.compress.compress(data) )
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            self.offset += len(data)
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        return len(data)
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    def read(self, size=-1):
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        self._check_closed()
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        if self.mode != READ:
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            import errno
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            raise OSError(errno.EBADF, "read() on write-only GzipFile object")
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        if self.extrasize <= 0 and self.fileobj is None:
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            return b''
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        readsize = 1024
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        if size < 0:        # get the whole thing
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            while self._read(readsize):
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                readsize = min(self.max_read_chunk, readsize * 2)
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            size = self.extrasize
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        else:               # just get some more of it
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            while size > self.extrasize:
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                if not self._read(readsize):
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                    if size > self.extrasize:
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                        size = self.extrasize
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                    break
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                readsize = min(self.max_read_chunk, readsize * 2)
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        offset = self.offset - self.extrastart
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        chunk = self.extrabuf[offset: offset + size]
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        self.extrasize = self.extrasize - size
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        self.offset += size
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        return chunk
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    def read1(self, size=-1):
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        self._check_closed()
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        if self.mode != READ:
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            import errno
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            raise OSError(errno.EBADF, "read1() on write-only GzipFile object")
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        if self.extrasize <= 0 and self.fileobj is None:
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            return b''
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        # For certain input data, a single call to _read() may not return
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        # any data. In this case, retry until we get some data or reach EOF.
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        while self.extrasize <= 0 and self._read():
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            pass
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        if size < 0 or size > self.extrasize:
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            size = self.extrasize
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        offset = self.offset - self.extrastart
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        chunk = self.extrabuf[offset: offset + size]
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        self.extrasize -= size
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        self.offset += size
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        return chunk
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    def peek(self, n):
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        if self.mode != READ:
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            import errno
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            raise OSError(errno.EBADF, "peek() on write-only GzipFile object")
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        # Do not return ridiculously small buffers, for one common idiom
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        # is to call peek(1) and expect more bytes in return.
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        if n < 100:
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            n = 100
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        if self.extrasize == 0:
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            if self.fileobj is None:
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                return b''
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            # Ensure that we don't return b"" if we haven't reached EOF.
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            # 1024 is the same buffering heuristic used in read()
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            while self.extrasize == 0 and self._read(max(n, 1024)):
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                pass
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        offset = self.offset - self.extrastart
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        remaining = self.extrasize
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        assert remaining == len(self.extrabuf) - offset
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        return self.extrabuf[offset:offset + n]
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    def _unread(self, buf):
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        self.extrasize = len(buf) + self.extrasize
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        self.offset -= len(buf)
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    def _read(self, size=1024):
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        if self.fileobj is None:
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            return False
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        if self._new_member:
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            # If the _new_member flag is set, we have to
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            # jump to the next member, if there is one.
 | 
						|
            self._init_read()
 | 
						|
            if not self._read_gzip_header():
 | 
						|
                return False
 | 
						|
            self.decompress = zlib.decompressobj(-zlib.MAX_WBITS)
 | 
						|
            self._new_member = False
 | 
						|
 | 
						|
        # Read a chunk of data from the file
 | 
						|
        buf = self.fileobj.read(size)
 | 
						|
 | 
						|
        # If the EOF has been reached, flush the decompression object
 | 
						|
        # and mark this object as finished.
 | 
						|
 | 
						|
        if buf == b"":
 | 
						|
            uncompress = self.decompress.flush()
 | 
						|
            # Prepend the already read bytes to the fileobj to they can be
 | 
						|
            # seen by _read_eof()
 | 
						|
            self.fileobj.prepend(self.decompress.unused_data, True)
 | 
						|
            self._read_eof()
 | 
						|
            self._add_read_data( uncompress )
 | 
						|
            return False
 | 
						|
 | 
						|
        uncompress = self.decompress.decompress(buf)
 | 
						|
        self._add_read_data( uncompress )
 | 
						|
 | 
						|
        if self.decompress.unused_data != b"":
 | 
						|
            # Ending case: we've come to the end of a member in the file,
 | 
						|
            # so seek back to the start of the unused data, finish up
 | 
						|
            # this member, and read a new gzip header.
 | 
						|
            # Prepend the already read bytes to the fileobj to they can be
 | 
						|
            # seen by _read_eof() and _read_gzip_header()
 | 
						|
            self.fileobj.prepend(self.decompress.unused_data, True)
 | 
						|
            # Check the CRC and file size, and set the flag so we read
 | 
						|
            # a new member on the next call
 | 
						|
            self._read_eof()
 | 
						|
            self._new_member = True
 | 
						|
        return True
 | 
						|
 | 
						|
    def _add_read_data(self, data):
 | 
						|
        self.crc = zlib.crc32(data, self.crc) & 0xffffffff
 | 
						|
        offset = self.offset - self.extrastart
 | 
						|
        self.extrabuf = self.extrabuf[offset:] + data
 | 
						|
        self.extrasize = self.extrasize + len(data)
 | 
						|
        self.extrastart = self.offset
 | 
						|
        self.size = self.size + len(data)
 | 
						|
 | 
						|
    def _read_eof(self):
 | 
						|
        # We've read to the end of the file
 | 
						|
        # We check the that the computed CRC and size of the
 | 
						|
        # uncompressed data matches the stored values.  Note that the size
 | 
						|
        # stored is the true file size mod 2**32.
 | 
						|
        crc32, isize = struct.unpack("<II", self._read_exact(8))
 | 
						|
        if crc32 != self.crc:
 | 
						|
            raise OSError("CRC check failed %s != %s" % (hex(crc32),
 | 
						|
                                                         hex(self.crc)))
 | 
						|
        elif isize != (self.size & 0xffffffff):
 | 
						|
            raise OSError("Incorrect length of data produced")
 | 
						|
 | 
						|
        # Gzip files can be padded with zeroes and still have archives.
 | 
						|
        # Consume all zero bytes and set the file position to the first
 | 
						|
        # non-zero byte. See http://www.gzip.org/#faq8
 | 
						|
        c = b"\x00"
 | 
						|
        while c == b"\x00":
 | 
						|
            c = self.fileobj.read(1)
 | 
						|
        if c:
 | 
						|
            self.fileobj.prepend(c, True)
 | 
						|
 | 
						|
    @property
 | 
						|
    def closed(self):
 | 
						|
        return self.fileobj is None
 | 
						|
 | 
						|
    def close(self):
 | 
						|
        if self.fileobj is None:
 | 
						|
            return
 | 
						|
        if self.mode == WRITE:
 | 
						|
            self.fileobj.write(self.compress.flush())
 | 
						|
            write32u(self.fileobj, self.crc)
 | 
						|
            # self.size may exceed 2GB, or even 4GB
 | 
						|
            write32u(self.fileobj, self.size & 0xffffffff)
 | 
						|
            self.fileobj = None
 | 
						|
        elif self.mode == READ:
 | 
						|
            self.fileobj = None
 | 
						|
        if self.myfileobj:
 | 
						|
            self.myfileobj.close()
 | 
						|
            self.myfileobj = None
 | 
						|
 | 
						|
    def flush(self,zlib_mode=zlib.Z_SYNC_FLUSH):
 | 
						|
        self._check_closed()
 | 
						|
        if self.mode == WRITE:
 | 
						|
            # Ensure the compressor's buffer is flushed
 | 
						|
            self.fileobj.write(self.compress.flush(zlib_mode))
 | 
						|
            self.fileobj.flush()
 | 
						|
 | 
						|
    def fileno(self):
 | 
						|
        """Invoke the underlying file object's fileno() method.
 | 
						|
 | 
						|
        This will raise AttributeError if the underlying file object
 | 
						|
        doesn't support fileno().
 | 
						|
        """
 | 
						|
        return self.fileobj.fileno()
 | 
						|
 | 
						|
    def rewind(self):
 | 
						|
        '''Return the uncompressed stream file position indicator to the
 | 
						|
        beginning of the file'''
 | 
						|
        if self.mode != READ:
 | 
						|
            raise OSError("Can't rewind in write mode")
 | 
						|
        self.fileobj.seek(0)
 | 
						|
        self._new_member = True
 | 
						|
        self.extrabuf = b""
 | 
						|
        self.extrasize = 0
 | 
						|
        self.extrastart = 0
 | 
						|
        self.offset = 0
 | 
						|
 | 
						|
    def readable(self):
 | 
						|
        return self.mode == READ
 | 
						|
 | 
						|
    def writable(self):
 | 
						|
        return self.mode == WRITE
 | 
						|
 | 
						|
    def seekable(self):
 | 
						|
        return True
 | 
						|
 | 
						|
    def seek(self, offset, whence=0):
 | 
						|
        if whence:
 | 
						|
            if whence == 1:
 | 
						|
                offset = self.offset + offset
 | 
						|
            else:
 | 
						|
                raise ValueError('Seek from end not supported')
 | 
						|
        if self.mode == WRITE:
 | 
						|
            if offset < self.offset:
 | 
						|
                raise OSError('Negative seek in write mode')
 | 
						|
            count = offset - self.offset
 | 
						|
            chunk = bytes(1024)
 | 
						|
            for i in range(count // 1024):
 | 
						|
                self.write(chunk)
 | 
						|
            self.write(bytes(count % 1024))
 | 
						|
        elif self.mode == READ:
 | 
						|
            if offset < self.offset:
 | 
						|
                # for negative seek, rewind and do positive seek
 | 
						|
                self.rewind()
 | 
						|
            count = offset - self.offset
 | 
						|
            for i in range(count // 1024):
 | 
						|
                self.read(1024)
 | 
						|
            self.read(count % 1024)
 | 
						|
 | 
						|
        return self.offset
 | 
						|
 | 
						|
    def readline(self, size=-1):
 | 
						|
        if size < 0:
 | 
						|
            # Shortcut common case - newline found in buffer.
 | 
						|
            offset = self.offset - self.extrastart
 | 
						|
            i = self.extrabuf.find(b'\n', offset) + 1
 | 
						|
            if i > 0:
 | 
						|
                self.extrasize -= i - offset
 | 
						|
                self.offset += i - offset
 | 
						|
                return self.extrabuf[offset: i]
 | 
						|
 | 
						|
            size = sys.maxsize
 | 
						|
            readsize = self.min_readsize
 | 
						|
        else:
 | 
						|
            readsize = size
 | 
						|
        bufs = []
 | 
						|
        while size != 0:
 | 
						|
            c = self.read(readsize)
 | 
						|
            i = c.find(b'\n')
 | 
						|
 | 
						|
            # We set i=size to break out of the loop under two
 | 
						|
            # conditions: 1) there's no newline, and the chunk is
 | 
						|
            # larger than size, or 2) there is a newline, but the
 | 
						|
            # resulting line would be longer than 'size'.
 | 
						|
            if (size <= i) or (i == -1 and len(c) > size):
 | 
						|
                i = size - 1
 | 
						|
 | 
						|
            if i >= 0 or c == b'':
 | 
						|
                bufs.append(c[:i + 1])    # Add portion of last chunk
 | 
						|
                self._unread(c[i + 1:])   # Push back rest of chunk
 | 
						|
                break
 | 
						|
 | 
						|
            # Append chunk to list, decrease 'size',
 | 
						|
            bufs.append(c)
 | 
						|
            size = size - len(c)
 | 
						|
            readsize = min(size, readsize * 2)
 | 
						|
        if readsize > self.min_readsize:
 | 
						|
            self.min_readsize = min(readsize, self.min_readsize * 2, 512)
 | 
						|
        return b''.join(bufs) # Return resulting line
 | 
						|
 | 
						|
 | 
						|
def compress(data, compresslevel=9):
 | 
						|
    """Compress data in one shot and return the compressed string.
 | 
						|
    Optional argument is the compression level, in range of 0-9.
 | 
						|
    """
 | 
						|
    buf = io.BytesIO()
 | 
						|
    with GzipFile(fileobj=buf, mode='wb', compresslevel=compresslevel) as f:
 | 
						|
        f.write(data)
 | 
						|
    return buf.getvalue()
 | 
						|
 | 
						|
def decompress(data):
 | 
						|
    """Decompress a gzip compressed string in one shot.
 | 
						|
    Return the decompressed string.
 | 
						|
    """
 | 
						|
    with GzipFile(fileobj=io.BytesIO(data)) as f:
 | 
						|
        return f.read()
 | 
						|
 | 
						|
 | 
						|
def _test():
 | 
						|
    # Act like gzip; with -d, act like gunzip.
 | 
						|
    # The input file is not deleted, however, nor are any other gzip
 | 
						|
    # options or features supported.
 | 
						|
    args = sys.argv[1:]
 | 
						|
    decompress = args and args[0] == "-d"
 | 
						|
    if decompress:
 | 
						|
        args = args[1:]
 | 
						|
    if not args:
 | 
						|
        args = ["-"]
 | 
						|
    for arg in args:
 | 
						|
        if decompress:
 | 
						|
            if arg == "-":
 | 
						|
                f = GzipFile(filename="", mode="rb", fileobj=sys.stdin.buffer)
 | 
						|
                g = sys.stdout.buffer
 | 
						|
            else:
 | 
						|
                if arg[-3:] != ".gz":
 | 
						|
                    print("filename doesn't end in .gz:", repr(arg))
 | 
						|
                    continue
 | 
						|
                f = open(arg, "rb")
 | 
						|
                g = builtins.open(arg[:-3], "wb")
 | 
						|
        else:
 | 
						|
            if arg == "-":
 | 
						|
                f = sys.stdin.buffer
 | 
						|
                g = GzipFile(filename="", mode="wb", fileobj=sys.stdout.buffer)
 | 
						|
            else:
 | 
						|
                f = builtins.open(arg, "rb")
 | 
						|
                g = open(arg + ".gz", "wb")
 | 
						|
        while True:
 | 
						|
            chunk = f.read(1024)
 | 
						|
            if not chunk:
 | 
						|
                break
 | 
						|
            g.write(chunk)
 | 
						|
        if g is not sys.stdout.buffer:
 | 
						|
            g.close()
 | 
						|
        if f is not sys.stdin.buffer:
 | 
						|
            f.close()
 | 
						|
 | 
						|
if __name__ == '__main__':
 | 
						|
    _test()
 |