Part of twisted.names._rfc1982 View Source View In Hierarchy

An RFC1982 Serial Number.

This class implements RFC1982 DNS Serial Number Arithmetic.

SNA is used in DNS and specifically in DNSSEC as defined in RFC4034 in the DNSSEC Signature Expiration and Inception Fields.

See Also | https://tools.ietf.org/html/rfc1982 | |

https://tools.ietf.org/html/rfc4034 |

Method | __init__ | Construct an `SerialNumber`
instance. |

Method | __str__ | Return a string representation of this `SerialNumber`
instance. |

Method | __int__ | |

Method | __eq__ | Allow rich equality comparison with another `SerialNumber`
instance. |

Method | __ne__ | Allow rich equality comparison with another `SerialNumber`
instance. |

Method | __lt__ | Allow less than comparison with another `SerialNumber`
instance. |

Method | __gt__ | Allow greater than comparison with another `SerialNumber`
instance. |

Method | __le__ | Allow less than or equal comparison with another `SerialNumber`
instance. |

Method | __ge__ | Allow greater than or equal comparison with another `SerialNumber`
instance. |

Method | __add__ | Allow addition with another `SerialNumber`
instance. |

Method | __hash__ | Allow `SerialNumber`
instances to be hashed for use as `dict` keys. |

Class Method | fromRFC4034DateString | Create an `SerialNumber`
instance from a date string in format 'YYYYMMDDHHMMSS' described in RFC4034 3.2. |

Method | toRFC4034DateString | Calculate a date by treating the current `SerialNumber`
value as a UNIX timestamp and return a date string in the format described
in RFC4034 3.2. |

Instance Variable | _serialBits | See `serialBits` of `__init__` . |

Instance Variable | _number | See `number` of `__init__` . |

Instance Variable | _modulo | The value at which wrapping will occur. |

Instance Variable | _halfRing | Half `_modulo` . If another `SerialNumber`
value is larger than this, it would lead to a wrapped value which is larger
than the first and comparisons are therefore ambiguous. |

Instance Variable | _maxAdd | Half `_modulo` plus 1. If another `SerialNumber`
value is larger than this, it would lead to a wrapped value which is larger
than the first. Comparisons with the original value would therefore be
ambiguous. |

Method | _convertOther | Check that a foreign object is suitable for use in the comparison or
arithmetic magic methods of this `SerialNumber`
instance. Raise `TypeError`
if not. |

_halfRing =

Half

`_modulo`

. If another `SerialNumber`

value is larger than this, it would lead to a wrapped value which is larger
than the first and comparisons are therefore ambiguous.
_maxAdd =

Half

`_modulo`

plus 1. If another `SerialNumber`

value is larger than this, it would lead to a wrapped value which is larger
than the first. Comparisons with the original value would therefore be
ambiguous.
def
__init__(self, number, serialBits=32):
(source)

Construct an

`SerialNumber`

instance.Parameters | number | An `int`
which will be stored as the modulo `number % 2 ^ serialBits` (type: `int` ) |

serialBits | The size of the serial number space. The power of two which results in one
larger than the largest integer corresponding to a serial number value. (type: `int` ) |

def
_convertOther(self, other):
(source)

Check that a foreign object is suitable for use in the comparison or
arithmetic magic methods of this

`SerialNumber`

instance. Raise `TypeError`

if not.Parameters | other | The foreign `object`
to be checked. |

Returns | `other` after compatibility checks and possible coercion. | |

Raises | `TypeError`
if `other` is not compatible. |

def
__str__(self):
(source)

Return a string representation of this

`SerialNumber`

instance.Returns | (type: `nativeString` ) |

def
__eq__(self, other):
(source)

Allow rich equality comparison with another

`SerialNumber`

instance.
def
__ne__(self, other):
(source)

Allow rich equality comparison with another

`SerialNumber`

instance.
def
__add__(self, other):
(source)

Allow *addition* with another

`SerialNumber`

instance.
Serial numbers may be incremented by the addition of a positive integer n, where n is taken from the range of integers [0 .. (2^(SERIAL_BITS - 1) - 1)]. For a sequence number s, the result of such an addition, s', is defined as

s' = (s + n) modulo (2 ^ SERIAL_BITS)

where the addition and modulus operations here act upon values that are non-negative values of unbounded size in the usual ways of integer arithmetic.

Addition of a value outside the range [0 .. (2^(SERIAL_BITS - 1) - 1)] is undefined.

Returns | (type: `SerialNumber` ) | |

Raises | `ArithmeticError`
if `other` is more than `_maxAdd` ie more than half
the maximum value of this serial number. | |

See Also | http://tools.ietf.org/html/rfc1982#section-3.1 |

@classmethod

def fromRFC4034DateString(cls, utcDateString): (source)

def fromRFC4034DateString(cls, utcDateString): (source)

Create an

`SerialNumber`

instance from a date string in format 'YYYYMMDDHHMMSS' described in RFC4034 3.2.
The `SerialNumber`

instance stores the date as a 32bit UNIX timestamp.

Parameters | utcDateString | A UTC date/time string of format YYMMDDhhmmss which will be
converted to seconds since the UNIX epoch. (type: `unicode` ) |

Returns | An `SerialNumber`
instance containing the supplied date as a 32bit UNIX timestamp. | |

See Also | https://tools.ietf.org/html/rfc4034#section-3.1.5 |

def
toRFC4034DateString(self):
(source)

Calculate a date by treating the current

`SerialNumber`

value as a UNIX timestamp and return a date string in the format described
in RFC4034 3.2.Returns | The date string. |