import atexit
import sys


if sys.version_info < (3, 0):
    def _encode_string(s):
        if isinstance(s, bytes):
            return s
        else:
            return s.encode('latin1')

    def _decode_string(b):
        return b
else:
    def _encode_string(s):
        encoded = s.encode('latin1')
        return encoded

    def _decode_string(b):
        return b.decode('latin1')

_encode_string.__doc__ = """Encode a string for use by LLVM."""
_decode_string.__doc__ = """Decode a LLVM character (byte)string."""


_shutting_down = [False]

def _at_shutdown():
    _shutting_down[0] = True

atexit.register(_at_shutdown)

def _is_shutting_down(_shutting_down=_shutting_down):
    """
    Whether the interpreter is currently shutting down.
    For use in finalizers, __del__ methods, and similar; it is advised
    to early bind this function rather than look it up when calling it,
    since at shutdown module globals may be cleared.
    """
    return _shutting_down[0]