LRU cache

<pre name="code" class="cpp">/*
 * common.h
 *
 *  Created on: 2015年8月17日
 *      Author: qiangqaz
 */

#ifndef COMMON_H_
#define COMMON_H_

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

typedef unsigned char		u8;
typedef unsigned short		u16;
typedef unsigned int		u32;
typedef unsigned long long	u64;
typedef signed char		s8;
typedef short			s16;
typedef int			s32;
typedef long long		s64;

#define min(x,y) ({ \
	typeof(x) _x = (x);	\
	typeof(y) _y = (y);	\
	(void) (&_x == &_y);	\
	_x < _y ? _x : _y; })

#define max(x,y) ({ \
	typeof(x) _x = (x);	\
	typeof(y) _y = (y);	\
	(void) (&_x == &_y);	\
	_x > _y ? _x : _y; })

/*
 * swap - swap value of @a and @b
 */
#define swap(a, b) \
	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)

#define USHORT_MAX	((u16)(~0U))
#define SHORT_MAX	((s16)(USHORT_MAX>>1))
#define SHORT_MIN	(-SHORT_MAX - 1)
#define INT_MAX		((int)(~0U>>1))
#define INT_MIN		(-INT_MAX - 1)
#define UINT_MAX	(~0U)
#define LONG_MAX	((long)(~0UL>>1))
#define LONG_MIN	(-LONG_MAX - 1)
#define ULONG_MAX	(~0UL)
#define LLONG_MAX	((long long)(~0ULL>>1))
#define LLONG_MIN	(-LLONG_MAX - 1)
#define ULLONG_MAX	(~0ULL)



#ifndef offset_of
#define offset_of(type, memb) \
	((unsigned long)(&((type *)0)->memb))
#endif
#ifndef container_of
#define container_of(obj, type, memb) \
	((type *)(((char *)obj) - offset_of(type, memb)))
#endif


/* print function stack address: __builtin_return_address(0) */


#endif /* COMMON_H_ */

/*
 * LRU.h
 *
 *  Created on: 2016年2月26日
 *      Author: qiangqaz
 */

#ifndef LRU_H_
#define LRU_H_

typedef struct S_LRU_LIST
{
	u32 data;
	struct list_head d_list;
}LRU_LIST;
typedef struct S_LRU
{
	u32 max_len;
	u32 cur_len;
	int (*func)(int, int);
	struct list_head lru_head;
}LRU;


LRU* LRU_init(u32 length);
void LRU_destroy(LRU **lru);
int LRU_insert(LRU *lru, u32 key);
int LRU_get(LRU *lru, u32 key);

#endif /* LRU_H_ */

/*
 * list.h
 *
 *  Created on: 2015年8月17日
 *      Author: qiangqaz
 */

#ifndef LIST_H_
#define LIST_H_

struct list_head {
	struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
	struct list_head name = LIST_HEAD_INIT(name)

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	list->next = list;
	list->prev = list;
}

static inline void __list_add(struct list_head *_new, struct list_head *prev, struct list_head *next)
{
	next->prev = _new;
	_new->next = next;
	_new->prev = prev;
	prev->next = _new;
}

/**
 * list_add - add a _new entry
 * @_new: _new entry to be added
 * @head: list head to add it after
 *
 * Insert a _new entry after the specified head.
 * This is good for implementing stacks.
 */
static inline void list_add(struct list_head *_new, struct list_head *head)
{
	__list_add(_new, head, head->next);
}


/**
 * list_add_tail - add a _new entry
 * @_new: _new entry to be added
 * @head: list head to add it before
 *
 * Insert a _new entry before the specified head.
 * This is useful for implementing queues.
 */
static inline void list_add_tail(struct list_head *_new, struct list_head *head)
{
	__list_add(_new, head->prev, head);
}

/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
	next->prev = prev;
	prev->next = next;
}

/**
 * list_del - deletes entry from list.
 * @entry: the element to delete from the list.
 * Note: list_empty() on entry does not return true after this, the entry is
 * in an undefined state.
 */
static inline void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	entry->next = 0;
	entry->prev = 0;
}
static inline void list_move(struct list_head *list, struct list_head *head)
{
	__list_del(list->prev, list->next);
	list_add(list, head);
}
/**
 * list_empty - tests whether a list is empty
 * @head: the list to test.
 */
static inline int list_empty(const struct list_head *head)
{
	return head->next == head;
}
/**
 * list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 */
#define list_for_each(pos, head) \
	for (pos = (head)->next; prefetch(pos->next), pos != (head); \
        	pos = pos->next)

/*
 * LRU.c
 *
 *  Created on: 2016年2月26日
 *      Author: qiangqaz
 */
#include <stdio.h>
#include <stdlib.h>
#include "common.h"
#include "list.h"
#include "LRU.h"


int LRU_Compare(int data, int key)
{
	if (key == data)
		return 0;
	else
		return 1;
}
LRU* LRU_init(u32 length)
{
	LRU *lru = NULL;

	lru = (LRU* )malloc(sizeof(LRU));
	if (NULL == lru)
	{
		return NULL;
	}
	lru->max_len = length;
	lru->cur_len = 0;
	lru->func = &LRU_Compare;
	INIT_LIST_HEAD(&(lru->lru_head));

	return lru;
}
void LRU_destroy(LRU **lru_del)
{
	LRU_LIST *lru_list = NULL;
	struct list_head *pos;
	LRU *lru = *lru_del;

	if (lru == NULL)
	{
		return;
	}

	while (!list_empty(&lru->lru_head))
	{
		pos = lru->lru_head.next;
		list_del(pos);
		lru_list = container_of(pos, LRU_LIST, d_list);
		free(lru_list);
	}
	/*
	for (pos = lru->lru_head.next; pos != &(lru->lru_head);pos = lru->lru_head.next)
	{
		lru_list = container_of(pos, LRU_LIST, d_list);
		list_del(pos);
		free(lru_list);
	}
	*/
	free(lru);
	lru = NULL;
}

int LRU_insert(LRU *lru, u32 key)
{
	LRU_LIST *lru_list = NULL;
	struct list_head *pos = NULL;

	if (lru == NULL)
		return -1;

	if (lru->cur_len >= lru->max_len)
	{
		pos = lru->lru_head.prev;
		list_move(pos, &(lru->lru_head));
		lru_list = container_of(pos, LRU_LIST, d_list);
		lru_list->data = key;
		return 0;
	}
	lru_list = malloc(sizeof(LRU_LIST));
	lru_list->data = key;

	list_add(&(lru_list->d_list), &(lru->lru_head));
	lru->cur_len++;

	return 0;
}

int LRU_get(LRU *lru, u32 key)
{
	LRU_LIST *lru_list = NULL;
	struct list_head *pos;

	if (lru == NULL)
		return -1;

	__list_for_each(pos, &(lru->lru_head))
	{
		lru_list = container_of(pos, LRU_LIST, d_list);
		if (0 == lru->func(lru_list->data, key))
		{
			list_move(pos, &(lru->lru_head));
		}
	}

	return -1;
}

<pre name="code" class="cpp">/*
 ============================================================================
 Name        : main.c
 Author      : 
 Version     :
 Copyright   : Your copyright notice
 Description : Hello World in C, Ansi-style
 ============================================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include "common.h"
#include "list.h"
#include "LRU.h"

void lru_print(LRU *lru)
{
	LRU_LIST *lru_list = NULL;
	struct list_head *pos;

	__list_for_each(pos, &(lru->lru_head))
	{
		lru_list = container_of(pos, LRU_LIST, d_list);
		printf("%d\n",lru_list->data);
	}
}
int main(void)
{
	LRU *lru = NULL;

	lru = LRU_init(10);

	LRU_insert(lru, 10);
	LRU_insert(lru, 13);
	LRU_insert(lru, 8);
	LRU_insert(lru, 45);
	LRU_insert(lru, 4545);
	LRU_insert(lru, 123);
	LRU_insert(lru, 64);
	LRU_insert(lru, 55);
	LRU_insert(lru, 23);
	LRU_insert(lru, 53);
	LRU_insert(lru, 78);
	LRU_insert(lru, 96);
	lru_print(lru);
	printf("begin to get key=4545\n");
	(void)LRU_get(lru, 4545);
	lru_print(lru);
	printf("begin to get key=123\n");
	(void)LRU_get(lru, 123);
	lru_print(lru);
	LRU_destroy(&lru);
	return EXIT_SUCCESS;
}