from django.core.cache import cache

from hashlib import sha1

from django.conf import settings

# adapted [to django] from http://code.activestate.com/recipes/325205/

def dj_memoize(f):

    def g(*args, **kwargs):

        key = sha1( str((settings.SITE_URL, f.__name__, f, tuple(args), frozenset(kwargs.items())) )).hexdigest()

        val = cache.get(key)

        if not val:

            val = f(*args, **kwargs)

            cache.set(key,val)

        return val

    return g

# adapted from http://code.activestate.com/recipes/496879/

# decorator with LRU policy

# changed : 

#  - default limit is 100

#  - store sha1 of key (shorter) 

import cPickle, hashlib

def memoize(function, limit=100):

    if isinstance(function, int):

        def memoize_wrapper(f):

            return memoize(f, function)

        return memoize_wrapper

    dict = {}

    list = []

    def memoize_wrapper(*args, **kwargs):

        key = hashlib.sha1(cPickle.dumps((args, kwargs))).digest()

        try:

            list.append(list.pop(list.index(key)))

        except ValueError:

            dict[key] = function(*args, **kwargs)

            list.append(key)

            if limit is not None and len(list) > limit:

                del dict[list.pop(0)]

        return dict[key]

    memoize_wrapper._memoize_dict = dict

    memoize_wrapper._memoize_list = list

    memoize_wrapper._memoize_limit = limit

    memoize_wrapper._memoize_origfunc = function

    memoize_wrapper.func_name = function.func_name

    return memoize_wrapper