Libubox/list linux

【Libubox/list】list是创建双向循环链表的实用程序。只需向结构中添加struct list_head。它附带了很多迭代器宏。下面逐个看一下。
1.container_of宏：知道结构体类型，成员地址求结构体地址。其中ptr:成员地址，typ：结构体类型，member：成员指示器

#ifndef container_of #define container_of(ptr, type, member)\ ({\ const __typeof__(((type *) NULL)->member) *__mptr = (ptr); \ (type *) ((char *) __mptr - offsetof(type, member)); \ }) #endif

2.结构体和创建变量宏,#define LIST_HEAD_INIT(name) { &(name), &(name) }这句非常经典

struct list_head { struct list_head *next; struct list_head *prev; }; //创建变量宏 #define LIST_HEAD_INIT(name) { &(name), &(name) }

3.创建链表

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

4.判断链表是否为空

static inline bool list_empty(const struct list_head *head) { return (head->next == head); }

5.判断list节点是否为首节点

static inline bool list_is_first(const struct list_head *list, const struct list_head *head) { return list->prev == head; }

6.判断list是否为尾节点

static inline void list_add_tail(struct list_head *_new, struct list_head *head) { _list_add(_new, head->prev, head); }

7.删除节点

static inline void _list_del(struct list_head *entry) { entry->next->prev = entry->prev; entry->prev->next = entry->next; }static inline void list_del(struct list_head *entry) { _list_del(entry); entry->next = entry->prev = NULL; }

8.添加节点

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; }

9.将节点entry从链表中分出来（entry未释放）

static inline void list_del_init(struct list_head *entry) { _list_del(entry); INIT_LIST_HEAD(entry); }

10.链表遍历宏

//遍历链表 #define list_for_each(p, head)\ for (p = (head)->next; p != (head); p = p->next)

11.链表遍历的实现

#define list_entry(ptr, type, field) container_of(ptr, type, field) #define list_first_entry(ptr, type, field) list_entry((ptr)->next, type, field) #define list_last_entry(ptr, type, field) list_entry((ptr)->prev, type, field) //迭代 #define list_for_each_safe(p, n, head)\ for (p = (head)->next, n = p->next; p != (head); p = n, n = p->next)#define list_for_each_entry(p, h, field)\ for (p = list_first_entry(h, __typeof__(*p), field); &p->field != (h); \ p = list_entry(p->field.next, __typeof__(*p), field))#define list_for_each_entry_safe(p, n, h, field)\ for (p = list_first_entry(h, __typeof__(*p), field),\ n = list_entry(p->field.next, __typeof__(*p), field); &p->field != (h); \ p = n, n = list_entry(n->field.next, __typeof__(*n), field))#define list_for_each_entry_reverse(p, h, field)\ for (p = list_last_entry(h, __typeof__(*p), field); &p->field != (h); \ p = list_entry(p->field.prev, __typeof__(*p), field))#define list_for_each_prev(p, h) for (p = (h)->prev; p != (h); p = p->prev) #define list_for_each_prev_safe(p, n, h) for (p = (h)->prev, n = p->prev; p != (h); p = n, n = p->prev)

12.链表插入和拼接

//从头插入节点 static inline void list_add(struct list_head *_new, struct list_head *head) { _list_add(_new, head, head->next); } //从尾插入节点 static inline void list_add_tail(struct list_head *_new, struct list_head *head) { _list_add(_new, head->prev, head); } //移动list到头部 static inline void list_move(struct list_head *list, struct list_head *head) { _list_del(list); list_add(list, head); } //移动list到尾部 static inline void list_move_tail(struct list_head *entry, struct list_head *head) { _list_del(entry); list_add_tail(entry, head); } //链表拼接 static inline void _list_splice(const struct list_head *list, struct list_head *prev, struct list_head *next) { struct list_head *first; struct list_head *last; if (list_empty(list)) return; first = list->next; last = list->prev; first->prev = prev; prev->next = first; last->next = next; next->prev = last; }static inline void list_splice(const struct list_head *list, struct list_head *head) { _list_splice(list, head, head->next); }static inline void list_splice_tail(struct list_head *list, struct list_head *head) { _list_splice(list, head->prev, head); }static inline void list_splice_init(struct list_head *list, struct list_head *head) { _list_splice(list, head, head->next); INIT_LIST_HEAD(list); }static inline void list_splice_tail_init(struct list_head *list, struct list_head *head) { _list_splice(list, head->prev, head); INIT_LIST_HEAD(list); }