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3098 rajveer 1 
'''
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Created on 30-Aug-2011
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@author: rajveer
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'''
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import time
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class memoized(object):
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    '''
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    Simple caching for function returns.
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    Any function return can be memoized for a given time duration.
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    Time to live also need to be mentioned. It is represented as number of seconds
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    '''
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    def __init__(self, ttl):
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        self.cache = {}
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        self.ttl = ttl
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    def __call__(self, func):
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        def wrapped_function(*args):
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            try:
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                now = time.time()
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                value, last_update = self.cache[args]
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                if now - last_update > self.ttl:
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                    print "EXPIRED"
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                    raise AttributeError
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                print "HIT"
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            except KeyError:
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                print "MISS"
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                value = func(*args)
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                self.cache[args] = value, now
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            except AttributeError:
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                value = func(*args)
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                self.cache[args] = value, now
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            except TypeError:
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                print "MISS"
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                return func(*args)
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            return value
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        return wrapped_function
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    def __repr__(self):
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        return self.func.__doc__
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'''
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Example usage
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'''
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@memoized(0)
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def fibonacci(n):
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    if n <= 1:
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        return n
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    return fibonacci(n-2) + fibonacci(n-1)
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def main():
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    print fibonacci(10)
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    print fibonacci(12)
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if __name__ == '__main__':
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    main()