2 * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #ifndef __NSCD_CACHEPLCS_H__
28 #define __NSCD_CACHEPLCS_H__
30 #include <sys/queue.h>
32 /* common policy definitions */
33 #define CACHELIB_MAX_FREQUENCY 100
36 * cache_policy_item_ represents some abstract cache element in the policy
37 * queue. connected_item pointers to the corresponding cache_policy_item_ in
38 * another policy queue.
40 struct cache_policy_item_ {
45 struct timeval last_request_time;
46 struct timeval creation_time;
48 struct cache_policy_item_ *connected_item;
52 * cache_policy_ represents an abstract policy queue. It can be customized by
53 * setting appropriate function pointers
55 struct cache_policy_ {
56 struct cache_policy_item_* (*create_item_func)(void);
57 void (*destroy_item_func)(struct cache_policy_item_ *);
59 void (*add_item_func)(struct cache_policy_ *,
60 struct cache_policy_item_ *);
61 void (*remove_item_func)(struct cache_policy_ *,
62 struct cache_policy_item_ *);
63 void (*update_item_func)(struct cache_policy_ *,
64 struct cache_policy_item_ *);
66 struct cache_policy_item_ *(*get_first_item_func)(
67 struct cache_policy_ *);
68 struct cache_policy_item_ *(*get_last_item_func)(
69 struct cache_policy_ *);
70 struct cache_policy_item_ *(*get_next_item_func)(
71 struct cache_policy_ *, struct cache_policy_item_ *);
72 struct cache_policy_item_ *(*get_prev_item_func)(
73 struct cache_policy_ *, struct cache_policy_item_ *);
77 * LFU cache policy item "inherited" from cache_policy_item_ structure
79 struct cache_lfu_policy_item_ {
80 struct cache_policy_item_ parent_data;
83 TAILQ_ENTRY(cache_lfu_policy_item_) entries;
86 TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
89 * LFU policy queue "inherited" from cache_policy_.
91 struct cache_lfu_policy_ {
92 struct cache_policy_ parent_data;
93 struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
97 * LRU and FIFO policies item "inherited" from cache_policy_item_
99 struct cache_queue_policy_item_ {
100 struct cache_policy_item_ parent_data;
101 TAILQ_ENTRY(cache_queue_policy_item_) entries;
105 * LRU and FIFO policies "inherited" from cache_policy_
107 struct cache_queue_policy_ {
108 struct cache_policy_ parent_data;
109 TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
112 typedef struct cache_queue_policy_ cache_fifo_policy_;
113 typedef struct cache_queue_policy_ cache_lru_policy_;
115 /* fifo policy routines */
116 struct cache_policy_ *init_cache_fifo_policy(void);
117 void destroy_cache_fifo_policy(struct cache_policy_ *);
119 /* lru policy routines */
120 struct cache_policy_ *init_cache_lru_policy(void);
121 void destroy_cache_lru_policy(struct cache_policy_ *);
123 /* lfu policy routines */
124 struct cache_policy_ *init_cache_lfu_policy(void);
125 void destroy_cache_lfu_policy(struct cache_policy_ *);