def open(file, mode="r", buffering=-1,
         encoding=None, errors=None,
         newline=None, closefd=True):

    r"""Open file and return a stream.  Raise IOError upon failure.

    file is either a text or byte string giving the name (and the path
    if the file isn't in the current working directory) of the file to
    be opened or an integer file descriptor of the file to be
    wrapped. (If a file descriptor is given, it is closed when the
    returned I/O object is closed, unless closefd is set to False.)

    mode is an optional string that specifies the mode in which the file
    is opened. It defaults to 'r' which means open for reading in text
    mode.  Other common values are 'w' for writing (truncating the file if
    it already exists), and 'a' for appending (which on some Unix systems,
    means that all writes append to the end of the file regardless of the
    current seek position). In text mode, if encoding is not specified the
    encoding used is platform dependent. (For reading and writing raw
    bytes use binary mode and leave encoding unspecified.) The available
    modes are:

    ========= ===============================================================
    Character Meaning
    --------- ---------------------------------------------------------------
    'r'       open for reading (default)
    'w'       open for writing, truncating the file first
    'a'       open for writing, appending to the end of the file if it exists
    'b'       binary mode
    't'       text mode (default)
    '+'       open a disk file for updating (reading and writing)
    'U'       universal newline mode (for backwards compatibility; unneeded
              for new code)
    ========= ===============================================================

    The default mode is 'rt' (open for reading text). For binary random
    access, the mode 'w+b' opens and truncates the file to 0 bytes, while
    'r+b' opens the file without truncation.

    Python distinguishes between files opened in binary and text modes,
    even when the underlying operating system doesn't. Files opened in
    binary mode (appending 'b' to the mode argument) return contents as
    bytes objects without any decoding. In text mode (the default, or when
    't' is appended to the mode argument), the contents of the file are
    returned as strings, the bytes having been first decoded using a
    platform-dependent encoding or using the specified encoding if given.

    buffering is an optional integer used to set the buffering policy.
    Pass 0 to switch buffering off (only allowed in binary mode), 1 to select
    line buffering (only usable in text mode), and an integer > 1 to indicate
    the size of a fixed-size chunk buffer.  When no buffering argument is
    given, the default buffering policy works as follows:

    * Binary files are buffered in fixed-size chunks; the size of the buffer
      is chosen using a heuristic trying to determine the underlying device's
      "block size" and falling back on `io.DEFAULT_BUFFER_SIZE`.
      On many systems, the buffer will typically be 4096 or 8192 bytes long.

    * "Interactive" text files (files for which isatty() returns True)
      use line buffering.  Other text files use the policy described above
      for binary files.

    encoding is the name of the encoding used to decode or encode the
    file. This should only be used in text mode. The default encoding is
    platform dependent, but any encoding supported by Python can be
    passed.  See the codecs module for the list of supported encodings.

    errors is an optional string that specifies how encoding errors are to
    be handled---this argument should not be used in binary mode. Pass
    'strict' to raise a ValueError exception if there is an encoding error
    (the default of None has the same effect), or pass 'ignore' to ignore
    errors. (Note that ignoring encoding errors can lead to data loss.)
    See the documentation for codecs.register for a list of the permitted
    encoding error strings.

    newline controls how universal newlines works (it only applies to text
    mode). It can be None, '', '\n', '\r', and '\r\n'.  It works as
    follows:

    * On input, if newline is None, universal newlines mode is
      enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
      these are translated into '\n' before being returned to the
      caller. If it is '', universal newline mode is enabled, but line
      endings are returned to the caller untranslated. If it has any of
      the other legal values, input lines are only terminated by the given
      string, and the line ending is returned to the caller untranslated.

    * On output, if newline is None, any '\n' characters written are
      translated to the system default line separator, os.linesep. If
      newline is '', no translation takes place. If newline is any of the
      other legal values, any '\n' characters written are translated to
      the given string.

    If closefd is False, the underlying file descriptor will be kept open
    when the file is closed. This does not work when a file name is given
    and must be True in that case.

    open() returns a file object whose type depends on the mode, and
    through which the standard file operations such as reading and writing
    are performed. When open() is used to open a file in a text mode ('w',
    'r', 'wt', 'rt', etc.), it returns a TextIOWrapper. When used to open
    a file in a binary mode, the returned class varies: in read binary
    mode, it returns a BufferedReader; in write binary and append binary
    modes, it returns a BufferedWriter, and in read/write mode, it returns
    a BufferedRandom.

    It is also possible to use a string or bytearray as a file for both
    reading and writing. For strings StringIO can be used like a file
    opened in a text mode, and for bytes a BytesIO can be used like a file
    opened in a binary mode.
    """
    if not isinstance(file, (basestring, int, long)):
        raise TypeError("invalid file: %r" % file)
    if not isinstance(mode, basestring):
        raise TypeError("invalid mode: %r" % mode)
    if not isinstance(buffering, (int, long)):
        raise TypeError("invalid buffering: %r" % buffering)
    if encoding is not None and not isinstance(encoding, basestring):
        raise TypeError("invalid encoding: %r" % encoding)
    if errors is not None and not isinstance(errors, basestring):
        raise TypeError("invalid errors: %r" % errors)
    modes = set(mode)
    if modes - set("arwb+tU") or len(mode) > len(modes):
        raise ValueError("invalid mode: %r" % mode)
    reading = "r" in modes
    writing = "w" in modes
    appending = "a" in modes
    updating = "+" in modes
    text = "t" in modes
    binary = "b" in modes
    if "U" in modes:
        if writing or appending:
            raise ValueError("can't use U and writing mode at once")
        reading = True
    if text and binary:
        raise ValueError("can't have text and binary mode at once")
    if reading + writing + appending > 1:
        raise ValueError("can't have read/write/append mode at once")
    if not (reading or writing or appending):
        raise ValueError("must have exactly one of read/write/append mode")
    if binary and encoding is not None:
        raise ValueError("binary mode doesn't take an encoding argument")
    if binary and errors is not None:
        raise ValueError("binary mode doesn't take an errors argument")
    if binary and newline is not None:
        raise ValueError("binary mode doesn't take a newline argument")
    raw = FileIO(file,
                 (reading and "r" or "") +
                 (writing and "w" or "") +
                 (appending and "a" or "") +
                 (updating and "+" or ""),
                 closefd)
    line_buffering = False
    if buffering == 1 or buffering < 0 and raw.isatty():
        buffering = -1
        line_buffering = True
    if buffering < 0:
        buffering = DEFAULT_BUFFER_SIZE
        try:
            bs = os.fstat(raw.fileno()).st_blksize
        except (os.error, __HOLE__):
            pass
        else:
            if bs > 1:
                buffering = bs
    if buffering < 0:
        raise ValueError("invalid buffering size")
    if buffering == 0:
        if binary:
            return raw
        raise ValueError("can't have unbuffered text I/O")
    if updating:
        buffer = BufferedRandom(raw, buffering)
    elif writing or appending:
        buffer = BufferedWriter(raw, buffering)
    elif reading:
        buffer = BufferedReader(raw, buffering)
    else:
        raise ValueError("unknown mode: %r" % mode)
    if binary:
        return buffer
    text = TextIOWrapper(buffer, encoding, errors, newline, line_buffering)
    text.mode = mode
    return text
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/_pyio.py/open