/*-
* Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef __NSCD_CACHEPLCS_H__
#define __NSCD_CACHEPLCS_H__
#include <sys/queue.h>
/* common policy definitions */
#define CACHELIB_MAX_FREQUENCY 100
/*
* cache_policy_item_ represents some abstract cache element in the policy
* queue. connected_item pointers to the corresponding cache_policy_item_ in
* another policy queue.
*/
struct cache_policy_item_ {
char *key;
size_t key_size;
size_t request_count;
struct timeval last_request_time;
struct timeval creation_time;
struct cache_policy_item_ *connected_item;
};
/*
* cache_policy_ represents an abstract policy queue. It can be customized by
* setting appropriate function pointers
*/
struct cache_policy_ {
struct cache_policy_item_* (*create_item_func)(void);
void (*destroy_item_func)(struct cache_policy_item_ *);
void (*add_item_func)(struct cache_policy_ *,
struct cache_policy_item_ *);
void (*remove_item_func)(struct cache_policy_ *,
struct cache_policy_item_ *);
void (*update_item_func)(struct cache_policy_ *,
struct cache_policy_item_ *);
struct cache_policy_item_ *(*get_first_item_func)(
struct cache_policy_ *);
struct cache_policy_item_ *(*get_last_item_func)(
struct cache_policy_ *);
struct cache_policy_item_ *(*get_next_item_func)(
struct cache_policy_ *, struct cache_policy_item_ *);
struct cache_policy_item_ *(*get_prev_item_func)(
struct cache_policy_ *, struct cache_policy_item_ *);
};
/*
* LFU cache policy item "inherited" from cache_policy_item_ structure
*/
struct cache_lfu_policy_item_ {
struct cache_policy_item_ parent_data;
int frequency;
TAILQ_ENTRY(cache_lfu_policy_item_) entries;
};
TAILQ_HEAD(cache_lfu_policy_group_, cache_lfu_policy_item_);
/*
* LFU policy queue "inherited" from cache_policy_.
*/
struct cache_lfu_policy_ {
struct cache_policy_ parent_data;
struct cache_lfu_policy_group_ groups[CACHELIB_MAX_FREQUENCY];
};
/*
* LRU and FIFO policies item "inherited" from cache_policy_item_
*/
struct cache_queue_policy_item_ {
struct cache_policy_item_ parent_data;
TAILQ_ENTRY(cache_queue_policy_item_) entries;
};
/*
* LRU and FIFO policies "inherited" from cache_policy_
*/
struct cache_queue_policy_ {
struct cache_policy_ parent_data;
TAILQ_HEAD(cache_queue_policy_head_, cache_queue_policy_item_) head;
};
typedef struct cache_queue_policy_ cache_fifo_policy_;
typedef struct cache_queue_policy_ cache_lru_policy_;
/* fifo policy routines */
struct cache_policy_ *init_cache_fifo_policy(void);
void destroy_cache_fifo_policy(struct cache_policy_ *);
/* lru policy routines */
struct cache_policy_ *init_cache_lru_policy(void);
void destroy_cache_lru_policy(struct cache_policy_ *);
/* lfu policy routines */
struct cache_policy_ *init_cache_lfu_policy(void);
void destroy_cache_lfu_policy(struct cache_policy_ *);
#endif
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