diff options
| -rw-r--r-- | rfc1982_serial_number.py | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/rfc1982_serial_number.py b/rfc1982_serial_number.py index 2d884a2..a8c29d7 100644 --- a/rfc1982_serial_number.py +++ b/rfc1982_serial_number.py @@ -2,17 +2,21 @@ class Serial: + _modulus = 2 ** 32 + _bitmask = _modulus - 1 + _signbit = _modulus >> 1 + def __init__(self, val): - self._val = int(val) % 2**32 + self._val = int(val) & self._bitmask - def __int__(self): - return self._val + def __add__(self, val): + return self.__class__(self._val + int(val)) - def __str__(self): - return str(int(self)) + def __le__(self, other): + return (self._modulus - int(self) + int(other)) & self._signbit == 0 - def __add__(self, val): - return Serial(self._val + int(val)) + def __ge__(self, other): + return (self._modulus + int(self) - int(other)) & self._signbit == 0 def __eq__(self, other): return int(self) == int(other) @@ -21,14 +25,16 @@ class Serial: return int(self) != int(other) def __lt__(self, other): - return self != other and ( - (int(self) < int(other) and int(other) - int(self) < 2**31) or - (int(self) > int(other) and int(self) - int(other) > 2**31)) + return self != other and self <= other def __gt__(self, other): - return self != other and ( - (int(self) < int(other) and int(other) - int(self) > 2**31) or - (int(self) > int(other) and int(self) - int(other) < 2**31)) + return self != other and self >= other + + def __int__(self): + return self._val + + def __str__(self): + return str(int(self)) if __name__ == "__main__": from random import randint |