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60 lines
1.2 KiB
Python
60 lines
1.2 KiB
Python
# -*- coding: utf-8 -*-
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import collections
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import threading
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from .func import locked
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__all__ = ['LRU']
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class LRU(object):
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"""
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Implementation of a length-limited O(1) LRU map.
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Original Copyright 2003 Josiah Carlson, later rebuilt on OrderedDict.
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"""
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def __init__(self, count, pairs=()):
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self._lock = threading.RLock()
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self.count = max(count, 1)
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self.d = collections.OrderedDict()
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for key, value in pairs:
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self[key] = value
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@locked
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def __contains__(self, obj):
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return obj in self.d
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def get(self, obj, val=None):
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try:
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return self[obj]
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except KeyError:
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return val
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@locked
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def __getitem__(self, obj):
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a = self.d[obj]
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self.d.move_to_end(obj, last=False)
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return a
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@locked
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def __setitem__(self, obj, val):
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self.d[obj] = val
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self.d.move_to_end(obj, last=False)
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while len(self.d) > self.count:
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self.d.popitem(last=True)
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@locked
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def __delitem__(self, obj):
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del self.d[obj]
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@locked
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def __len__(self):
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return len(self.d)
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@locked
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def pop(self,key):
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return self.d.pop(key)
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@locked
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def clear(self):
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self.d.clear()
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