/opt/imh-python/lib/python3.9
Edit: /opt/imh-python/lib/python3.9/gzip.py (21772B)
"""Functions that read and write gzipped files.
The user of the file doesn't have to worry about the compression,
but random access is not allowed."""
# based on Andrew Kuchling's minigzip.py distributed with the zlib module
import struct, sys, time, os
import zlib
import builtins
import io
import _compression
__all__ = ["BadGzipFile", "GzipFile", "open", "compress", "decompress"]
FTEXT, FHCRC, FEXTRA, FNAME, FCOMMENT = 1, 2, 4, 8, 16
READ, WRITE = 1, 2
_COMPRESS_LEVEL_FAST = 1
_COMPRESS_LEVEL_TRADEOFF = 6
_COMPRESS_LEVEL_BEST = 9
def open(filename, mode="rb", compresslevel=_COMPRESS_LEVEL_BEST,
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", "x", "xb", "a" or "ab" for
binary mode, or "rt", "wt", "xt" or "at" for text mode. The default mode is
"rb", and the default compresslevel is 9.
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, os.PathLike)):
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
# or unsigned.
output.write(struct.pack("
'
def _init_write(self, filename):
self.name = filename
self.crc = zlib.crc32(b"")
self.size = 0
self.writebuf = []
self.bufsize = 0
self.offset = 0 # Current file offset for seek(), tell(), etc
def _write_gzip_header(self, compresslevel):
self.fileobj.write(b'\037\213') # magic header
self.fileobj.write(b'\010') # compression method
try:
# RFC 1952 requires the FNAME field to be Latin-1. Do not
# include filenames that cannot be represented that way.
fname = os.path.basename(self.name)
if not isinstance(fname, bytes):
fname = fname.encode('latin-1')
if fname.endswith(b'.gz'):
fname = fname[:-3]
except UnicodeEncodeError:
fname = b''
flags = 0
if fname:
flags = FNAME
self.fileobj.write(chr(flags).encode('latin-1'))
mtime = self._write_mtime
if mtime is None:
mtime = time.time()
write32u(self.fileobj, int(mtime))
if compresslevel == _COMPRESS_LEVEL_BEST:
xfl = b'\002'
elif compresslevel == _COMPRESS_LEVEL_FAST:
xfl = b'\004'
else:
xfl = b'\000'
self.fileobj.write(xfl)
self.fileobj.write(b'\377')
if fname:
self.fileobj.write(fname + b'\000')
def write(self,data):
self._check_not_closed()
if self.mode != WRITE:
import errno
raise OSError(errno.EBADF, "write() on read-only GzipFile object")
if self.fileobj is None:
raise ValueError("write() on closed GzipFile object")
if isinstance(data, bytes):
length = len(data)
else:
# accept any data that supports the buffer protocol
data = memoryview(data)
length = data.nbytes
if length > 0:
self.fileobj.write(self.compress.compress(data))
self.size += length
self.crc = zlib.crc32(data, self.crc)
self.offset += length
return length
def read(self, size=-1):
self._check_not_closed()
if self.mode != READ:
import errno
raise OSError(errno.EBADF, "read() on write-only GzipFile object")
return self._buffer.read(size)
def read1(self, size=-1):
"""Implements BufferedIOBase.read1()
Reads up to a buffer's worth of data if size is negative."""
self._check_not_closed()
if self.mode != READ:
import errno
raise OSError(errno.EBADF, "read1() on write-only GzipFile object")
if size < 0:
size = io.DEFAULT_BUFFER_SIZE
return self._buffer.read1(size)
def peek(self, n):
self._check_not_closed()
if self.mode != READ:
import errno
raise OSError(errno.EBADF, "peek() on write-only GzipFile object")
return self._buffer.peek(n)
@property
def closed(self):
return self.fileobj is None
def close(self):
fileobj = self.fileobj
if fileobj is None:
return
self.fileobj = None
try:
if self.mode == WRITE:
fileobj.write(self.compress.flush())
write32u(fileobj, self.crc)
# self.size may exceed 2 GiB, or even 4 GiB
write32u(fileobj, self.size & 0xffffffff)
elif self.mode == READ:
self._buffer.close()
finally:
myfileobj = self.myfileobj
if myfileobj:
self.myfileobj = None
myfileobj.close()
def flush(self,zlib_mode=zlib.Z_SYNC_FLUSH):
self._check_not_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._buffer.seek(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=io.SEEK_SET):
if self.mode == WRITE:
if whence != io.SEEK_SET:
if whence == io.SEEK_CUR:
offset = self.offset + offset
else:
raise ValueError('Seek from end not supported')
if offset < self.offset:
raise OSError('Negative seek in write mode')
count = offset - self.offset
chunk = b'\0' * 1024
for i in range(count // 1024):
self.write(chunk)
self.write(b'\0' * (count % 1024))
elif self.mode == READ:
self._check_not_closed()
return self._buffer.seek(offset, whence)
return self.offset
def readline(self, size=-1):
self._check_not_closed()
return self._buffer.readline(size)
class _GzipReader(_compression.DecompressReader):
def __init__(self, fp):
super().__init__(_PaddedFile(fp), zlib.decompressobj,
wbits=-zlib.MAX_WBITS)
# Set flag indicating start of a new member
self._new_member = True
self._last_mtime = None
def _init_read(self):
self._crc = zlib.crc32(b"")
self._stream_size = 0 # Decompressed size of unconcatenated stream
def _read_exact(self, n):
'''Read exactly *n* bytes from `self._fp`
This method is required because self._fp may be unbuffered,
i.e. return short reads.
'''
data = self._fp.read(n)
while len(data) < n:
b = self._fp.read(n - len(data))
if not b:
raise EOFError("Compressed file ended before the "
"end-of-stream marker was reached")
data += b
return data
def _read_gzip_header(self):
magic = self._fp.read(2)
if magic == b'':
return False
if magic != b'\037\213':
raise BadGzipFile('Not a gzipped file (%r)' % magic)
(method, flag,
self._last_mtime) = struct.unpack("