"""Interface to the libbzip2 compression library.

This module provides a file interface, classes for incremental
(de)compression, and functions for one-shot (de)compression.
"""

__all__ = ["BZ2File", "BZ2Compressor", "BZ2Decompressor",
           "open", "compress", "decompress"]

__author__ = "Nadeem Vawda "

from builtins import open as _builtin_open
import io
import os
import warnings
import _compression

try:
    from threading import RLock
except ImportError:
    from dummy_threading import RLock

from _bz2 import BZ2Compressor, BZ2Decompressor


_MODE_CLOSED   = 0
_MODE_READ     = 1
# Value 2 no longer used
_MODE_WRITE    = 3


class BZ2File(_compression.BaseStream):

    """A file object providing transparent bzip2 (de)compression.

    A BZ2File can act as a wrapper for an existing file object, or refer
    directly to a named file on disk.

    Note that BZ2File provides a *binary* file interface - data read is
    returned as bytes, and data to be written should be given as bytes.
    """

    def __init__(self, filename, mode="r", buffering=None, compresslevel=9):
        """Open a bzip2-compressed file.

        If filename is a str, bytes, or PathLike object, it gives the
        name of the file to be opened. Otherwise, it should be a file
        object, which will be used to read or write the compressed data.

        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'.

        buffering is ignored. Its use is deprecated.

        If mode is 'w', 'x' or 'a', compresslevel can be a number between 1
        and 9 specifying the level of compression: 1 produces the least
        compression, and 9 (default) produces the most compression.

        If mode is 'r', the input file may be the concatenation of
        multiple compressed streams.
        """
        # This lock must be recursive, so that BufferedIOBase's
        # writelines() does not deadlock.
        self._lock = RLock()
        self._fp = None
        self._closefp = False
        self._mode = _MODE_CLOSED

        if buffering is not None:
            warnings.warn("Use of 'buffering' argument is deprecated",
                          DeprecationWarning)

        if not (1