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""" A pure Python Queue implementation modelled after mxQueue.
Copyright (c) 2000, Marc-Andre Lemburg; mailto:mal@lemburg.com
Copyright (c) 2000-2010, eGenix.com Software GmbH; mailto:info@egenix.com
See the documentation for further information on copyrights,
or contact the author. All Rights Reserved.
"""
__version__ = '0.1'
class UserQueue:
def __init__(self):
self.queue = []
self.headindex = 0
def push(self,x):
self.queue.append(x)
def pop(self):
headindex = self.headindex
queue = self.queue
x = queue[headindex]
queue[headindex] = None # del. reference
headindex = headindex + 1
if headindex > 100 and headindex > len(queue) / 2:
# compactify
self.queue = self.queue[headindex:]
self.headindex = 0
else:
self.headindex = headindex
return x
def not_empty(self):
return self.headindex != len(self.queue)
def head(self):
return self.queue[self.headindex]
def tail(self):
return self.queue[-1]
def __len__(self):
return len(self.queue) - self.headindex
def __repr__(self):
l = self.queue[self.headindex:]
l.reverse()
return '<UserQueue [%s]>' % repr(l)[1:-1]
def __str__(self):
l = self.queue[self.headindex:]
l.reverse()
return 'q' + repr(l)
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