练习一下linux中的list函数。

所有的list函数见 include/linux/list.h

自己从 include/linux/list.h 拷贝了一些函数到自己的list.c中，然后练习了一下。

没有别的目的，就是想熟练一下。毕竟linux内核代码中试用了大量的list函数。

list的函数太方便使用了。

文件：list.c

  1 #include <stdio.h>
  2 // #include <linux/list.h>
  3 
  4 struct list_head {
  5     struct list_head *next, *prev;
  6 };
  7 
  8 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  9 #define LIST_HEAD(name) 
 10         struct list_head name = LIST_HEAD_INIT(name)
 11 
 12 static inline void INIT_LIST_HEAD(struct list_head *list)
 13 {
 14     list->next = list;
 15     list->prev = list;
 16 }
 17 
 18 static inline void __list_add(struct list_head *new,
 19          struct list_head *prev,
 20          struct list_head *next) //ËüÖ»ÊÇ½«newÌí¼Óµ½prevºÍnextÖ®¼ä
 21 {
 22     next->prev = new;
 23     new->next = next;
 24     new->prev = prev;
 25     prev->next = new;
 26 }
 27 
 28 static inline void list_add_tail(struct list_head *new, struct list_head *head)
 29 {
 30     __list_add(new, head->prev, head);
 31 }
 32 
 33 static inline int list_empty(const struct list_head *head)
 34 {
 35     return head->next == head;
 36 }
 37 
 38 
 39 #undef offsetof
 40 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 41 
 42 /**
 43  *  * container_of - cast a member of a structure out to the containing structure
 44  *   * @ptr:        the pointer to the member.
 45  *    * @type:       the type of the container struct this is embedded in.
 46  *     * @member:     the name of the member within the struct.
 47  *      *
 48  *       */
 49 #define container_of(ptr, type, member) ({                      
 50         const typeof( ((type *)0)->member ) *__mptr = (ptr);    
 51         (type *)( (char *)__mptr - offsetof(type,member) );})
 52 
 53 
 54 #define list_entry(ptr, type, member) 
 55         container_of(ptr, type, member)
 56 
 57 
 58 /**
 59  *  * list_for_each_entry  -       iterate over list of given type
 60  *   * @pos:        the type * to use as a loop cursor.
 61  *    * @head:       the head for your list.
 62  *     * @member:     the name of the list_struct within the struct.
 63  *      */
 64 #define list_for_each_entry(pos, head, member)                          
 65         for (pos = list_entry((head)->next, typeof(*pos), member);      
 66              &pos->member != (head);    
 67              pos = list_entry(pos->member.next, typeof(*pos), member))
 68 
 69 #define list_for_each(pos, head) 
 70         for (pos = (head)->next; pos != (head); pos = pos->next)
 71 
 72 
 73 struct devlist {
 74         struct list_head        list;
 75         char * name;
 76 };
 77 
 78 struct devlist dev0 = {
 79         .list = LIST_HEAD_INIT(dev0.list),
 80         .name = NULL,
 81 };
 82 
 83 /* static initiate head list*/
 84 // LIST_HEAD(hl);
 85 struct list_head hl = LIST_HEAD_INIT(hl);
 86 
 87 void main(void) {
 88     /* dynamic initiate head list. */
 89     INIT_LIST_HEAD(&hl);
 90     struct list_head *l;
 91     struct devlist * pdev = NULL; 
 92     int empty = list_empty(&hl);
 93     if(empty)
 94         printf("the device list is empty!
"); 
 95     struct devlist dev1; 
 96     dev1.name = "device1";
 97     list_add_tail(&dev1.list, &hl);
 98     struct devlist edev1 = {{}, "entry device1"};
 99     list_add_tail(&edev1.list, &dev0.list);
100     struct devlist dev2 = {{}, "device2"};
101     list_add_tail(&dev2.list, &hl);
102     struct devlist edev2 = {{}, "entry device2"};
103     list_add_tail(&edev2.list, &dev0.list);
104 
105     empty = list_empty(&hl);
106     if(!empty)
107         printf("the device list is not empty!
"); 
108      
109     list_for_each_entry(pdev, &dev0.list, list){
110             printf("the device name is %s
", pdev->name);
111     }
112 
113     list_for_each(l, &hl) {
114     // for (l = (&hl)->next; l != (&hl); l = l->next){
115     //         printf("l is: %p, head is: %p 
", l, &hl);
116             pdev = list_entry(l, typeof(dev0), list);
117             printf("the device name is %s
", pdev->name); 
118     }
119 }

输出结果：

1 $ ./list 
2 the device list is empty!
3 the device list is not empty!
4 the device name is entry device1
5 the device name is entry device2
6 the device name is device1
7 the device name is device2