from uuid import UUID, uuid4, _uuid_generate_random
try:
    import ctypes
except ImportError:
    ctypes = None


def gen_unique_id():
    """Generate a unique id, having - hopefully - a very small chance of
    collission.

    For now this is provided by :func:`uuid.uuid4`.
    """
    # Workaround for http://bugs.python.org/issue4607
    if ctypes and _uuid_generate_random:
        buffer = ctypes.create_string_buffer(16)
        _uuid_generate_random(buffer)
        return str(UUID(bytes=buffer.raw))
    return str(uuid4())


def _compat_rl_partition(S, sep, direction=str.split):
    items = direction(S, sep, 1)
    if len(items) == 1:
        return items[0], sep, ''
    return items[0], sep, items[1]


def _compat_partition(S, sep):
    """``partition(S, sep) -> (head, sep, tail)``

    Search for the separator ``sep`` in ``S``, and return the part before
    it, the separator itself, and the part after it. If the separator is not
    found, return ``S`` and two empty strings.

    """
    return _compat_rl_partition(S, sep, direction=str.split)


def _compat_rpartition(S, sep):
    """``rpartition(S, sep) -> (tail, sep, head)``

    Search for the separator ``sep`` in ``S``, starting at the end of ``S``,
    and return the part before it, the separator itself, and the part
    after it. If the separator is not found, return two empty
    strings and ``S``.

    """
    return _compat_rl_partition(S, sep, direction=str.rsplit)

try:
    partition = str.partition
    rpartition = str.rpartition
except AttributeError: # Python <= 2.4
    partition = _compat_partition
    rpartition = _compat_rpartition