C语言双向循环链表api（源自gluster源码）

C语言双向循环链表api（源自gluster源码） 基本的操作如增加、删除和遍历等

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*定义表头*/
struct list_head {
struct list_head *next;
struct list_head *prev;
};

/*表头初始化*/
#define INIT_LIST_HEAD(head) do {           \
(head)->next = (head)->prev = head; \
} while (0)

/*增加*/
static inline void
list_add (struct list_head *new, struct list_head *head)
{
new->prev = head;
new->next = head->next;

new->prev->next = new;
new->next->prev = new;
}

/*删除*/
static inline void
list_del (struct list_head *old)
{
old->prev->next = old->next;
old->next->prev = old->prev;

old->next = (void *)0xbabebabe;
old->prev = (void *)0xcafecafe;
}

/*判断链表是否为空*/
static inline int
list_empty (struct list_head *head)
{
return (head->next == head);
}

#define list_entry(ptr, type, member)                   \
((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))

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

/*遍历，关于list_for_each_entry，百度*/
#define list_for_each_entry(pos, head, member)              \
for (pos = list_entry((head)->next, typeof(*pos), member);  \
&pos->member != (head);                    \
pos = list_entry(pos->member.next, typeof(*pos), member))

/*例：先定义一个结构体*/
typedef struct student
{
int num;        //学号
int score;      //分数
char name[20];
struct list_head student_list;
}STU;

STU *head=NULL;

int main(void)
{
STU *new=NULL;

new = (STU *)malloc(sizeof(STU));
bzero(new, sizeof(STU));
new->num = 8;
new->score = 8;
strcpy(new->name, "8888");
/*链表初始化*/
if(head == NULL)
{
// head = (STU *)malloc(sizeof(STU));
// bzero(head, sizeof(STU));
head = new;
INIT_LIST_HEAD(&head->student_list);
}
else
{
list_add(&new->student_list, &head->student_list);
}

if(list_empty(&head->student_list))
{
printf("list only head\n");
printf("head->num:%d, score:%d, name:%s\n", head->num, head->score, head->name);
}
/*将新成员插入链表*/
int i;
for(i=0;i<5;i++)
{
new = (STU *)malloc(sizeof(STU));
bzero(new, sizeof(STU));
new->num = i;
new->score = i+1;
strcpy(new->name, "2233");
list_add(&new->student_list, &head->student_list);
}
/*删除指定的成员*/
STU *pos=NULL;
list_for_each_entry(pos, &head->student_list, student_list)
{
if(pos->num == 2){
list_del(&pos->student_list);
free(pos);
pos = NULL;
break;
// printf("num:%d, score:%d, name:%s\n", pos->num, pos->score, pos->name);
}
}
/*遍历链表*/
list_for_each_entry(pos, &head->student_list, student_list)
{
printf("num:%d, score:%d, name:%s\n", pos->num, pos->score, pos->name);
}
return 0;
}