import sys

PY3 = sys.version_info[0] == 3

if PY3:
    MAXSIZE = sys.maxsize

    def bytes_to_str(b):
        if isinstance(b, str):
            return b
        return str(b, 'utf8')

    def str_to_bytes(s):
        if isinstance(s, bytes):
            return s
        return s.encode('utf8')

    import urllib.parse
    unquote_plus = urllib.parse.unquote_plus
else:
    if sys.platform == "java":
        # Jython always uses 32 bits.
        MAXSIZE = int((1 << 31) - 1)
    else:
        # It's possible to have sizeof(long) != sizeof(Py_ssize_t).
        class X(object):
            def __len__(self):
                return 1 << 31
        try:
            len(X())
        except OverflowError:
            # 32-bit
            MAXSIZE = int((1 << 31) - 1)
        else:
            # 64-bit
            MAXSIZE = int((1 << 63) - 1)
            del X

    def bytes_to_str(s):
        if isinstance(s, unicode):
            return s.encode('utf-8')
        return s

    def str_to_bytes(s):
        if isinstance(s, unicode):
            return s.encode('utf8')
        return s

    import urllib
    unquote_plus = urllib.unquote_plus