# limited cache, using brute-force LRU implementation.  this is surprisingly
# efficient, especially for small caches (i.e. a few hundred items)

class Cache:

    def __init__(self, maxsize=100):
        self.cache = {}
        self.order = [] # least recently used first
        self.maxsize = maxsize

    def size(self):
        return len(self.cache)

    def get(self, key):
        value = self.cache[key]
        self.order.remove(key)
        self.order.append(key)
        return value

    def set(self, key, value):
        if self.cache.has_key(key):
            self.order.remove(key)
        elif len(self.cache) >= self.maxsize:
            del self.cache[self.order.pop(0)]
        self.cache[key] = value
        self.order.append(key)

if __name__ == "__main__":
    import test
    test.simple(Cache)