Linux内核双向循环链表分析

#include <stdio.h>

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

struct score
{
	int num;
	int math;
	struct list_head list;	
};


#define list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); pos = pos->next)

#define offsetof(TYPE, MEMBER)((size_t) &((TYPE*)0)->MEMBER)

#define container_of(ptr, type, member) ({			\
	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
	(type *)( (char *)__mptr - offsetof(type,member) );})

#define list_entry(ptr, type, member)\
	container_of(ptr, type, member)
	
	

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

static 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;	
}

static void list_add_tail(struct list_head *new, struct list_head *head)
{
	__list_add(new, head->prev, head);	
}

static void list_add(struct list_head *new, struct list_head *head)
{
	__list_add(new, head, head->next);
}

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

static void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
} 

int main()
{
		struct score stu1;
		struct score stu2;
		struct score stu3;
		struct score stu4;
		struct score stu5;
		struct score stu6;
		
		struct score *temp;
		struct list_head *pos;
		
		struct list_head score_head;
		
		INIT_LIST_HEAD(&score_head);
		
		stu1.num = 1;
		stu2.num = 2;
		stu3.num = 3;
		stu4.num = 4;
		stu5.num = 5;
		stu6.num = 6;
		
		stu1.math = 60;
		stu2.math = 70;
		stu3.math = 80;
		stu4.math = 90;
		stu5.math = 20;
		stu6.math = 30;
		
		//在表尾部插入 
		list_add_tail(&(stu1.list), &score_head);
		list_add_tail(&(stu2.list), &score_head);
		list_add_tail(&(stu3.list), &score_head);
		list_add_tail(&(stu4.list), &score_head);

		list_for_each(pos, &score_head)
		{
			temp = list_entry(pos, struct score, list);
			printf("num = %d, math = %d\n", temp->num, temp->math);
		}
		
		printf("\n");		
		
		//在表头插入 
		list_add(&(stu5.list), &score_head);
		list_add(&(stu6.list), &score_head);

		list_for_each(pos, &score_head)
		{
			temp = list_entry(pos, struct score, list);
			printf("num = %d, math = %d\n", temp->num, temp->math);
		}
		printf("\n");		
				
		//删除
		list_del(&(stu5.list)); 
		
		list_for_each(pos, &score_head)
		{
			temp = list_entry(pos, struct score, list);
			printf("num = %d, math = %d\n", temp->num, temp->math);
		}
		printf("\n");		
		
		return 0;
}