💾 Archived View for tris.fyi › pydoc › lzma captured on 2023-01-29 at 03:22:07. Gemini links have been rewritten to link to archived content
⬅️ Previous capture (2022-07-16)
-=-=-=-=-=-=-
Interface to the liblzma compression library. This module provides a class for reading and writing compressed files, classes for incremental (de)compression, and convenience functions for one-shot (de)compression. These classes and functions support both the XZ and legacy LZMA container formats, as well as raw compressed data streams.
LZMACompressor(format=FORMAT_XZ, check=-1, preset=None, filters=None) Create a compressor object for compressing data incrementally. format specifies the container format to use for the output. This can be FORMAT_XZ (default), FORMAT_ALONE, or FORMAT_RAW. check specifies the integrity check to use. For FORMAT_XZ, the default is CHECK_CRC64. FORMAT_ALONE and FORMAT_RAW do not support integrity checks; for these formats, check must be omitted, or be CHECK_NONE. The settings used by the compressor can be specified either as a preset compression level (with the 'preset' argument), or in detail as a custom filter chain (with the 'filters' argument). For FORMAT_XZ and FORMAT_ALONE, the default is to use the PRESET_DEFAULT preset level. For FORMAT_RAW, the caller must always specify a filter chain; the raw compressor does not support preset compression levels. preset (if provided) should be an integer in the range 0-9, optionally OR-ed with the constant PRESET_EXTREME. filters (if provided) should be a sequence of dicts. Each dict should have an entry for "id" indicating the ID of the filter, plus additional entries for options to the filter. For one-shot compression, use the compress() function instead.
compress(self, data, /) Provide data to the compressor object. Returns a chunk of compressed data if possible, or b'' otherwise. When you have finished providing data to the compressor, call the flush() method to finish the compression process.
flush(self, /) Finish the compression process. Returns the compressed data left in internal buffers. The compressor object may not be used after this method is called.
Create a decompressor object for decompressing data incrementally.
format
Specifies the container format of the input stream. If this is
FORMAT_AUTO (the default), the decompressor will automatically detect
whether the input is FORMAT_XZ or FORMAT_ALONE. Streams created with
FORMAT_RAW cannot be autodetected.
memlimit
Limit the amount of memory used by the decompressor. This will cause
decompression to fail if the input cannot be decompressed within the
given limit.
filters
A custom filter chain. This argument is required for FORMAT_RAW, and
not accepted with any other format. When provided, this should be a
sequence of dicts, each indicating the ID and options for a single
filter.
For one-shot decompression, use the decompress() function instead.
decompress(self, /, data, max_length=-1) Decompress *data*, returning uncompressed data as bytes. If *max_length* is nonnegative, returns at most *max_length* bytes of decompressed data. If this limit is reached and further output can be produced, *self.needs_input* will be set to ``False``. In this case, the next call to *decompress()* may provide *data* as b'' to obtain more of the output. If all of the input data was decompressed and returned (either because this was less than *max_length* bytes, or because *max_length* was negative), *self.needs_input* will be set to True. Attempting to decompress data after the end of stream is reached raises an EOFError. Any data found after the end of the stream is ignored and saved in the unused_data attribute.
check = <member 'check' of '_lzma.LZMADecompressor' objects> ID of the integrity check used by the input stream.
eof = <member 'eof' of '_lzma.LZMADecompressor' objects> True if the end-of-stream marker has been reached.
needs_input = <member 'needs_input' of '_lzma.LZMADecompressor' objects> True if more input is needed before more decompressed data can be produced.
unused_data = <member 'unused_data' of '_lzma.LZMADecompressor' objects> Data found after the end of the compressed stream.
Call to liblzma failed.
with_traceback(...)
Exception.with_traceback(tb) --
set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>
A file object providing transparent LZMA (de)compression.
An LZMAFile can act as a wrapper for an existing file object, or
refer directly to a named file on disk.
Note that LZMAFile provides a *binary* file interface - data read
is returned as bytes, and data to be written must be given as bytes.
close(self)
Flush and close the file.
May be called more than once without error. Once the file is
closed, any other operation on it will raise a ValueError.
detach(self, /) Disconnect this buffer from its underlying raw stream and return it. After the raw stream has been detached, the buffer is in an unusable state.
fileno(self) Return the file descriptor for the underlying file.
flush(self, /) Flush write buffers, if applicable. This is not implemented for read-only and non-blocking streams.
isatty(self, /) Return whether this is an 'interactive' stream. Return False if it can't be determined.
peek(self, size=-1)
Return buffered data without advancing the file position.
Always returns at least one byte of data, unless at EOF.
The exact number of bytes returned is unspecified.
read(self, size=-1)
Read up to size uncompressed bytes from the file.
If size is negative or omitted, read until EOF is reached.
Returns b"" if the file is already at EOF.
read1(self, size=-1)
Read up to size uncompressed bytes, while trying to avoid
making multiple reads from the underlying stream. Reads up to a
buffer's worth of data if size is negative.
Returns b"" if the file is at EOF.
readable(self) Return whether the file was opened for reading.
readinto(self, buffer, /)
readinto1(self, buffer, /)
readline(self, size=-1)
Read a line of uncompressed bytes from the file.
The terminating newline (if present) is retained. If size is
non-negative, no more than size bytes will be read (in which
case the line may be incomplete). Returns b'' if already at EOF.
readlines(self, hint=-1, /) Return a list of lines from the stream. hint can be specified to control the number of lines read: no more lines will be read if the total size (in bytes/characters) of all lines so far exceeds hint.
seek(self, offset, whence=0)
Change the file position.
The new position is specified by offset, relative to the
position indicated by whence. Possible values for whence are:
0: start of stream (default): offset must not be negative
1: current stream position
2: end of stream; offset must not be positive
Returns the new file position.
Note that seeking is emulated, so depending on the parameters,
this operation may be extremely slow.
seekable(self) Return whether the file supports seeking.
tell(self) Return the current file position.
truncate(...) Truncate file to size bytes. File pointer is left unchanged. Size defaults to the current IO position as reported by tell(). Returns the new size.
writable(self) Return whether the file was opened for writing.
write(self, data)
Write a bytes object to the file.
Returns the number of uncompressed bytes written, which is
always the length of data in bytes. Note that due to buffering,
the file on disk may not reflect the data written until close()
is called.
writelines(self, lines, /) Write a list of lines to stream. Line separators are not added, so it is usual for each of the lines provided to have a line separator at the end.
closed = <property object at 0x7f75e2d61620> True if this file is closed.
compress(data, format=1, check=-1, preset=None, filters=None)
Compress a block of data.
Refer to LZMACompressor's docstring for a description of the
optional arguments *format*, *check*, *preset* and *filters*.
For incremental compression, use an LZMACompressor instead.
decompress(data, format=0, memlimit=None, filters=None)
Decompress a block of data.
Refer to LZMADecompressor's docstring for a description of the
optional arguments *format*, *check* and *filters*.
For incremental decompression, use an LZMADecompressor instead.
is_check_supported(check_id, /) Test whether the given integrity check is supported. Always returns True for CHECK_NONE and CHECK_CRC32.
open(filename, mode='rb', *, format=None, check=-1, preset=None, filters=None, encoding=None, errors=None, newline=None)
Open an LZMA-compressed file in binary or text mode.
filename can be either an actual file name (given as a str, bytes,
or PathLike object), in which case the named file is opened, or it
can be an existing file object to read from or write to.
The mode argument can be "r", "rb" (default), "w", "wb", "x", "xb",
"a", or "ab" for binary mode, or "rt", "wt", "xt", or "at" for text
mode.
The format, check, preset and filters arguments specify the
compression settings, as for LZMACompressor, LZMADecompressor and
LZMAFile.
For binary mode, this function is equivalent to the LZMAFile
constructor: LZMAFile(filename, mode, ...). In this case, the
encoding, errors and newline arguments must not be provided.
For text mode, an LZMAFile object is created, and wrapped in an
io.TextIOWrapper instance with the specified encoding, error
handling behavior, and line ending(s).
CHECK_CRC32 = 1
CHECK_CRC64 = 4
CHECK_ID_MAX = 15
CHECK_NONE = 0
CHECK_SHA256 = 10
CHECK_UNKNOWN = 16
FILTER_ARM = 7
FILTER_ARMTHUMB = 8
FILTER_DELTA = 3
FILTER_IA64 = 6
FILTER_LZMA1 = 4611686018427387905
FILTER_LZMA2 = 33
FILTER_POWERPC = 5
FILTER_SPARC = 9
FILTER_X86 = 4
FORMAT_ALONE = 2
FORMAT_AUTO = 0
FORMAT_RAW = 3
FORMAT_XZ = 1
MF_BT2 = 18
MF_BT3 = 19
MF_BT4 = 20
MF_HC3 = 3
MF_HC4 = 4
MODE_FAST = 1
MODE_NORMAL = 2
PRESET_DEFAULT = 6
PRESET_EXTREME = 2147483648