C 语言设计模式(三) 双链表

              在C 语言中双链表的实现，已经有很多经典的实现，下面的代码，从 android 中摘取，事实上这段代码可能 google 的人最初从linux 的代码中学得，其实设置到了极限，都达到了设计的完美，那么大家几乎说就是一样了，因我完美是唯一的，对于同一个事物的抽线，最完美的表达是唯一的。

          

struct listnode{    struct listnode *next;    struct listnode *prev;};#define node_to_item(node, container, member) \    (container *) (((char*) (node)) - offsetof(container, member))#define list_declare(name) \    struct listnode name = { \        .next = &name, \        .prev = &name, \    }#define list_for_each(node, list) \    for (node = (list)->next; node != (list); node = node->next)#define list_for_each_reverse(node, list) \    for (node = (list)->prev; node != (list); node = node->prev)void list_init(struct listnode *list);void list_add_tail(struct listnode *list, struct listnode *item);void list_remove(struct listnode *item);#define list_empty(list) ((list) == (list)->next)#define list_head(list) ((list)->next)#define list_tail(list) ((list)->prev)

                摘录一段参考代码：

   

void service_for_each(void (*func)(struct service *svc)){    struct listnode *node;    struct service *svc;    list_for_each(node, &service_list) {        svc = node_to_item(node, struct service, slist);        func(svc);    }}

struct service *service_find_by_name(const char *name){    struct listnode *node;    struct service *svc;    list_for_each(node, &service_list) {        svc = node_to_item(node, struct service, slist);        if (!strcmp(svc->name, name)) {            return svc;        }    }    return 0;}