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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Lib/gzip.py | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Lib/gzip.py')
-rw-r--r-- | contrib/tools/python3/src/Lib/gzip.py | 668 |
1 files changed, 668 insertions, 0 deletions
diff --git a/contrib/tools/python3/src/Lib/gzip.py b/contrib/tools/python3/src/Lib/gzip.py new file mode 100644 index 0000000000..5b20e5ba69 --- /dev/null +++ b/contrib/tools/python3/src/Lib/gzip.py @@ -0,0 +1,668 @@ +"""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: + encoding = io.text_encoding(encoding) + 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("<L", value)) + +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 + essential functionality.""" + + def __init__(self, f, prepend=b''): + self._buffer = prepend + self._length = len(prepend) + self.file = f + self._read = 0 + + def read(self, size): + if self._read is None: + return self.file.read(size) + if self._read + size <= self._length: + read = self._read + self._read += size + return self._buffer[read:self._read] + else: + read = self._read + self._read = None + return self._buffer[read:] + \ + self.file.read(size-self._length+read) + + def prepend(self, prepend=b''): + if self._read is None: + self._buffer = prepend + else: # Assume data was read since the last prepend() call + self._read -= len(prepend) + return + self._length = len(self._buffer) + self._read = 0 + + def seek(self, off): + self._read = None + self._buffer = None + return self.file.seek(off) + + def seekable(self): + return True # Allows fast-forwarding even in unseekable streams + + +class BadGzipFile(OSError): + """Exception raised in some cases for invalid gzip files.""" + + +class GzipFile(_compression.BaseStream): + """The GzipFile class simulates most of the methods of a file object with + the exception of the truncate() method. + + This class only supports opening files in binary mode. If you need to open a + compressed file in text mode, use the gzip.open() function. + + """ + + # Overridden with internal file object to be closed, if only a filename + # is passed in + myfileobj = None + + def __init__(self, filename=None, mode=None, + compresslevel=_COMPRESS_LEVEL_BEST, fileobj=None, mtime=None): + """Constructor for the GzipFile class. + + At least one of fileobj and filename must be given a + non-trivial value. + + The new class instance is based on fileobj, which can be a regular + file, an io.BytesIO object, or any other object which simulates a file. + It defaults to None, in which case filename is opened to provide + a file object. + + When fileobj is not None, the filename argument is only used to be + included in the gzip file header, which may include the original + filename of the uncompressed file. It defaults to the filename of + fileobj, if discernible; otherwise, it defaults to the empty string, + and in this case the original filename is not included in the header. + + The mode argument can be any of 'r', 'rb', 'a', 'ab', 'w', 'wb', 'x', or + 'xb' depending on whether the file will be read or written. The default + is the mode of fileobj if discernible; otherwise, the default is 'rb'. + A mode of 'r' is equivalent to one of 'rb', and similarly for 'w' and + 'wb', 'a' and 'ab', and 'x' and 'xb'. + + The compresslevel argument is an integer from 0 to 9 controlling the + level of compression; 1 is fastest and produces the least compression, + and 9 is slowest and produces the most compression. 0 is no compression + at all. The default is 9. + + The mtime argument is an optional numeric timestamp to be written + to the last modification time field in the stream when compressing. + If omitted or None, the current time is used. + + """ + + if mode and ('t' in mode or 'U' in mode): + raise ValueError("Invalid mode: {!r}".format(mode)) + if mode and 'b' not in mode: + mode += 'b' + if fileobj is None: + fileobj = self.myfileobj = builtins.open(filename, mode or 'rb') + if filename is None: + filename = getattr(fileobj, 'name', '') + if not isinstance(filename, (str, bytes)): + filename = '' + else: + filename = os.fspath(filename) + origmode = mode + if mode is None: + mode = getattr(fileobj, 'mode', 'rb') + + if mode.startswith('r'): + self.mode = READ + raw = _GzipReader(fileobj) + self._buffer = io.BufferedReader(raw) + self.name = filename + + elif mode.startswith(('w', 'a', 'x')): + if origmode is None: + import warnings + warnings.warn( + "GzipFile was opened for writing, but this will " + "change in future Python releases. " + "Specify the mode argument for opening it for writing.", + FutureWarning, 2) + self.mode = WRITE + self._init_write(filename) + self.compress = zlib.compressobj(compresslevel, + zlib.DEFLATED, + -zlib.MAX_WBITS, + zlib.DEF_MEM_LEVEL, + 0) + self._write_mtime = mtime + else: + raise ValueError("Invalid mode: {!r}".format(mode)) + + self.fileobj = fileobj + + if self.mode == WRITE: + self._write_gzip_header(compresslevel) + + @property + def filename(self): + import warnings + warnings.warn("use the name attribute", DeprecationWarning, 2) + if self.mode == WRITE and self.name[-3:] != ".gz": + return self.name + ".gz" + return self.name + + @property + def mtime(self): + """Last modification time read from stream, or None""" + return self._buffer.raw._last_mtime + + def __repr__(self): + s = repr(self.fileobj) + return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>' + + 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, bytearray)): + 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) + + +def _read_exact(fp, n): + '''Read exactly *n* bytes from `fp` + + This method is required because fp may be unbuffered, + i.e. return short reads. + ''' + data = fp.read(n) + while len(data) < n: + b = 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(fp): + '''Read a gzip header from `fp` and progress to the end of the header. + + Returns last mtime if header was present or None otherwise. + ''' + magic = fp.read(2) + if magic == b'': + return None + + if magic != b'\037\213': + raise BadGzipFile('Not a gzipped file (%r)' % magic) + + (method, flag, last_mtime) = struct.unpack("<BBIxx", _read_exact(fp, 8)) + if method != 8: + raise BadGzipFile('Unknown compression method') + + if flag & FEXTRA: + # Read & discard the extra field, if present + extra_len, = struct.unpack("<H", _read_exact(fp, 2)) + _read_exact(fp, extra_len) + if flag & FNAME: + # Read and discard a null-terminated string containing the filename + while True: + s = fp.read(1) + if not s or s==b'\000': + break + if flag & FCOMMENT: + # Read and discard a null-terminated string containing a comment + while True: + s = fp.read(1) + if not s or s==b'\000': + break + if flag & FHCRC: + _read_exact(fp, 2) # Read & discard the 16-bit header CRC + return last_mtime + + +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_gzip_header(self): + last_mtime = _read_gzip_header(self._fp) + if last_mtime is None: + return False + self._last_mtime = last_mtime + return True + + def read(self, size=-1): + if size < 0: + return self.readall() + # size=0 is special because decompress(max_length=0) is not supported + if not size: + return b"" + + # For certain input data, a single + # call to decompress() may not return + # any data. In this case, retry until we get some data or reach EOF. + while True: + if self._decompressor.eof: + # Ending case: we've come to the end of a member in the file, + # so finish up this member, and read a new gzip header. + # Check the CRC and file size, and set the flag so we read + # a new member + self._read_eof() + self._new_member = True + self._decompressor = self._decomp_factory( + **self._decomp_args) + + if self._new_member: + # If the _new_member flag is set, we have to + # jump to the next member, if there is one. + self._init_read() + if not self._read_gzip_header(): + self._size = self._pos + return b"" + self._new_member = False + + # Read a chunk of data from the file + buf = self._fp.read(io.DEFAULT_BUFFER_SIZE) + + uncompress = self._decompressor.decompress(buf, size) + if self._decompressor.unconsumed_tail != b"": + self._fp.prepend(self._decompressor.unconsumed_tail) + elif self._decompressor.unused_data != b"": + # Prepend the already read bytes to the fileobj so they can + # be seen by _read_eof() and _read_gzip_header() + self._fp.prepend(self._decompressor.unused_data) + + if uncompress != b"": + break + if buf == b"": + raise EOFError("Compressed file ended before the " + "end-of-stream marker was reached") + + self._add_read_data( uncompress ) + self._pos += len(uncompress) + return uncompress + + def _add_read_data(self, data): + self._crc = zlib.crc32(data, self._crc) + self._stream_size = self._stream_size + len(data) + + def _read_eof(self): + # We've read to the end of the file + # We check 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", _read_exact(self._fp, 8)) + if crc32 != self._crc: + raise BadGzipFile("CRC check failed %s != %s" % (hex(crc32), + hex(self._crc))) + elif isize != (self._stream_size & 0xffffffff): + raise BadGzipFile("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._fp.read(1) + if c: + self._fp.prepend(c) + + def _rewind(self): + super()._rewind() + self._new_member = True + + +def _create_simple_gzip_header(compresslevel: int, + mtime = None) -> bytes: + """ + Write a simple gzip header with no extra fields. + :param compresslevel: Compresslevel used to determine the xfl bytes. + :param mtime: The mtime (must support conversion to a 32-bit integer). + :return: A bytes object representing the gzip header. + """ + if mtime is None: + mtime = time.time() + if compresslevel == _COMPRESS_LEVEL_BEST: + xfl = 2 + elif compresslevel == _COMPRESS_LEVEL_FAST: + xfl = 4 + else: + xfl = 0 + # Pack ID1 and ID2 magic bytes, method (8=deflate), header flags (no extra + # fields added to header), mtime, xfl and os (255 for unknown OS). + return struct.pack("<BBBBLBB", 0x1f, 0x8b, 8, 0, int(mtime), xfl, 255) + + +def compress(data, compresslevel=_COMPRESS_LEVEL_BEST, *, mtime=None): + """Compress data in one shot and return the compressed string. + + compresslevel sets the compression level in range of 0-9. + mtime can be used to set the modification time. The modification time is + set to the current time by default. + """ + if mtime == 0: + # Use zlib as it creates the header with 0 mtime by default. + # This is faster and with less overhead. + return zlib.compress(data, level=compresslevel, wbits=31) + header = _create_simple_gzip_header(compresslevel, mtime) + trailer = struct.pack("<LL", zlib.crc32(data), (len(data) & 0xffffffff)) + # Wbits=-15 creates a raw deflate block. + return (header + zlib.compress(data, level=compresslevel, wbits=-15) + + trailer) + + +def decompress(data): + """Decompress a gzip compressed string in one shot. + Return the decompressed string. + """ + decompressed_members = [] + while True: + fp = io.BytesIO(data) + if _read_gzip_header(fp) is None: + return b"".join(decompressed_members) + # Use a zlib raw deflate compressor + do = zlib.decompressobj(wbits=-zlib.MAX_WBITS) + # Read all the data except the header + decompressed = do.decompress(data[fp.tell():]) + if not do.eof or len(do.unused_data) < 8: + raise EOFError("Compressed file ended before the end-of-stream " + "marker was reached") + crc, length = struct.unpack("<II", do.unused_data[:8]) + if crc != zlib.crc32(decompressed): + raise BadGzipFile("CRC check failed") + if length != (len(decompressed) & 0xffffffff): + raise BadGzipFile("Incorrect length of data produced") + decompressed_members.append(decompressed) + data = do.unused_data[8:].lstrip(b"\x00") + + +def main(): + from argparse import ArgumentParser + parser = ArgumentParser(description= + "A simple command line interface for the gzip module: act like gzip, " + "but do not delete the input file.") + group = parser.add_mutually_exclusive_group() + group.add_argument('--fast', action='store_true', help='compress faster') + group.add_argument('--best', action='store_true', help='compress better') + group.add_argument("-d", "--decompress", action="store_true", + help="act like gunzip instead of gzip") + + parser.add_argument("args", nargs="*", default=["-"], metavar='file') + args = parser.parse_args() + + compresslevel = _COMPRESS_LEVEL_TRADEOFF + if args.fast: + compresslevel = _COMPRESS_LEVEL_FAST + elif args.best: + compresslevel = _COMPRESS_LEVEL_BEST + + for arg in args.args: + if args.decompress: + if arg == "-": + f = GzipFile(filename="", mode="rb", fileobj=sys.stdin.buffer) + g = sys.stdout.buffer + else: + if arg[-3:] != ".gz": + sys.exit(f"filename doesn't end in .gz: {arg!r}") + 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, + compresslevel=compresslevel) + else: + f = builtins.open(arg, "rb") + g = open(arg + ".gz", "wb") + while True: + chunk = f.read(io.DEFAULT_BUFFER_SIZE) + 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__': + main() |