119 lines
3.5 KiB
Python
119 lines
3.5 KiB
Python
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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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"""Serial Number Arthimetic from RFC 1982"""
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class Serial:
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def __init__(self, value: int, bits: int = 32):
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self.value = value % 2**bits
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self.bits = bits
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def __repr__(self):
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return f"dns.serial.Serial({self.value}, {self.bits})"
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def __eq__(self, other):
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if isinstance(other, int):
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other = Serial(other, self.bits)
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elif not isinstance(other, Serial) or other.bits != self.bits:
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return NotImplemented
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return self.value == other.value
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def __ne__(self, other):
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if isinstance(other, int):
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other = Serial(other, self.bits)
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elif not isinstance(other, Serial) or other.bits != self.bits:
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return NotImplemented
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return self.value != other.value
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def __lt__(self, other):
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if isinstance(other, int):
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other = Serial(other, self.bits)
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elif not isinstance(other, Serial) or other.bits != self.bits:
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return NotImplemented
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if self.value < other.value and other.value - self.value < 2 ** (self.bits - 1):
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return True
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elif self.value > other.value and self.value - other.value > 2 ** (
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self.bits - 1
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):
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return True
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else:
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return False
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def __le__(self, other):
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return self == other or self < other
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def __gt__(self, other):
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if isinstance(other, int):
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other = Serial(other, self.bits)
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elif not isinstance(other, Serial) or other.bits != self.bits:
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return NotImplemented
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if self.value < other.value and other.value - self.value > 2 ** (self.bits - 1):
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return True
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elif self.value > other.value and self.value - other.value < 2 ** (
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self.bits - 1
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):
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return True
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else:
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return False
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def __ge__(self, other):
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return self == other or self > other
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def __add__(self, other):
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v = self.value
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if isinstance(other, Serial):
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delta = other.value
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elif isinstance(other, int):
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delta = other
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else:
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raise ValueError
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if abs(delta) > (2 ** (self.bits - 1) - 1):
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raise ValueError
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v += delta
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v = v % 2**self.bits
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return Serial(v, self.bits)
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def __iadd__(self, other):
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v = self.value
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if isinstance(other, Serial):
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delta = other.value
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elif isinstance(other, int):
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delta = other
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else:
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raise ValueError
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if abs(delta) > (2 ** (self.bits - 1) - 1):
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raise ValueError
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v += delta
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v = v % 2**self.bits
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self.value = v
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return self
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def __sub__(self, other):
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v = self.value
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if isinstance(other, Serial):
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delta = other.value
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elif isinstance(other, int):
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delta = other
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else:
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raise ValueError
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if abs(delta) > (2 ** (self.bits - 1) - 1):
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raise ValueError
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v -= delta
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v = v % 2**self.bits
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return Serial(v, self.bits)
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def __isub__(self, other):
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v = self.value
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if isinstance(other, Serial):
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delta = other.value
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elif isinstance(other, int):
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delta = other
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else:
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raise ValueError
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if abs(delta) > (2 ** (self.bits - 1) - 1):
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raise ValueError
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v -= delta
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v = v % 2**self.bits
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self.value = v
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return self
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