Class LZMAFile

Lib/lzma.py:38–276

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

class LZMAFile(_streams.BaseStream):

    """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.
    """

    def __init__(self, filename=None, mode="r", *,
                 format=None, check=-1, preset=None, filters=None):
        """Open an LZMA-compressed file in binary 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.

        mode can be "r" for reading (default), "w" for (over)writing,
        "x" for creating exclusively, or "a" for appending. These can
        equivalently be given as "rb", "wb", "xb" and "ab" respectively.

        format specifies the container format to use for the file.
        If mode is "r", this defaults to FORMAT_AUTO. Otherwise, the
        default is FORMAT_XZ.

        check specifies the integrity check to use. This argument can
        only be used when opening a file for writing. 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.

        When opening a file for reading, the *preset* argument is not
        meaningful, and should be omitted. The *filters* argument should
        also be omitted, except when format is FORMAT_RAW (in which case
        it is required).

        When opening a file for writing, 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 ID of the filter, plus
        additional entries for options to the filter.
        """
        self._fp = None
        self._closefp = False
        self._mode = None