104 lines
2.8 KiB
Python
104 lines
2.8 KiB
Python
# This file is derived from the GPL program "PyPE"
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#
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# Copyright (C) 2003-2006 Josiah Carlson
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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class Node:
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def __init__(self, prev, me):
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self.prev = prev
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self.me = me
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self.next = None
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class LRU: #Implementation of a length-limited O(1) LRU cache
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def __init__(self, count):
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self.count = max(count, 2)
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self.d = {}
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self.first = None
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self.last = None
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def __contains__(self, obj):
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return obj in self.d
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def __getitem__(self, obj):
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return self.d[obj].me[1]
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def __setitem__(self, obj, val):
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if obj in self.d:
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del self[obj]
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nobj = Node(self.last, (obj, val))
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if self.first is None:
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self.first = nobj
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if self.last:
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self.last.next = nobj
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self.last = nobj
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self.d[obj] = nobj
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if len(self.d) > self.count:
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if self.first == self.last:
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self.first = None
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self.last = None
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return
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a = self.first
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a.next.prev = None
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self.first = a.next
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a.next = None
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del self.d[a.me[0]]
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del a
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def __delitem__(self, obj):
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nobj = self.d[obj]
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if nobj.prev:
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nobj.prev.next = nobj.next
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else:
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self.first = nobj.next
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if nobj.next:
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nobj.next.prev = nobj.prev
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else:
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self.last = nobj.prev
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del self.d[obj]
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def __iter__(self):
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cur = self.first
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while cur != None:
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cur2 = cur.next
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yield cur.me[1]
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cur = cur2
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raise StopIteration
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def iteritems(self):
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cur = self.first
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while cur != None:
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cur2 = cur.next
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yield cur.me
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cur = cur2
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raise StopIteration
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def iterkeys(self):
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return iter(self.d)
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def itervalues(self):
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for i,j in self.iteritems():
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yield j
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def keys(self):
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return [i for i,j in self.iteritems()]
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def values(self):
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return [j for i,j in self.iteritems()]
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def items(self):
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return [i for i in self.iteritems()]
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