25 lines
910 B
Python
25 lines
910 B
Python
from lbry.dht import constants
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class Distance:
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"""Calculate the XOR result between two string variables.
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Frequently we re-use one of the points so as an optimization
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we pre-calculate the value of that point.
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"""
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def __init__(self, key: bytes):
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if len(key) != constants.HASH_LENGTH:
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raise ValueError(f"invalid key length: {len(key)}")
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self.key = key
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self.val_key_one = int.from_bytes(key, 'big')
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def __call__(self, key_two: bytes) -> int:
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if len(key_two) != constants.HASH_LENGTH:
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raise ValueError(f"invalid length of key to compare: {len(key_two)}")
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val_key_two = int.from_bytes(key_two, 'big')
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return self.val_key_one ^ val_key_two
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def is_closer(self, key_a: bytes, key_b: bytes) -> bool:
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"""Returns true is `key_a` is closer to `key` than `key_b` is"""
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return self(key_a) < self(key_b)
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