- 论坛徽章:
- 0
|
九.怎样使用ns自己的链表
1.头文件 #include
2.初始化
1). 在节点中添加,包括了指向前驱和后继的节点。
#define LIST_ENTRY(type)
struct {
type *le_next; /* next element */
type **le_prev; /* address of previous next element */
}
2).定义一个链表,链表的类型为type,表头为lh_first
#define LIST_HEAD(name, type)
struct name {
type *lh_first; /* first element */
}
3)初始化链表
#define LIST_INIT(head) {
(head)->lh_first = NULL;
}
4)插入节点
#define LIST_INSERT_AFTER(listelm, elm, field) {
if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)
(listelm)->field.le_next->field.le_prev =
&(elm)->field.le_next;
(listelm)->field.le_next = (elm);
(elm)->field.le_prev = &(listelm)->field.le_next;
}
#define LIST_INSERT_BEFORE(listelm, elm, field) {
(elm)->field.le_prev = (listelm)->field.le_prev;
(elm)->field.le_next = (listelm);
*(listelm)->field.le_prev = (elm);
(listelm)->field.le_prev = &(elm)->field.le_next;
}
#define LIST_INSERT_HEAD(head, elm, field) {
if (((elm)->field.le_next = (head)->lh_first) != NULL)
(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
(head)->lh_first = (elm);
(elm)->field.le_prev = &(head)->lh_first;
}
5)删除节点
#define LIST_REMOVE(elm, field) { \
if ((elm)->field.le_next != NULL) \
(elm)->field.le_next->field.le_prev = \
(elm)->field.le_prev; \
*(elm)->field.le_prev = (elm)->field.le_next; \
}
6)一个例子
(1)定义节点类型
class MFlood_RTEntry {
friend class MFlood_RTable;
friend class MFlood;
public:
MFlood_RTEntry();
MFlood_RTEntry(nsaddr_t src,u_int32_t seq);
bool isNewSeq(u_int32_t seq); // old -> false, new->true
void addSeq(u_int32_t seq); // add a seqno to seqno array(rt_seqnos)
protected:
LIST_ENTRY(MFlood_RTEntry) rt_link;
nsaddr_t src_;
// u_int32_t seq_;
u_int32_t rt_seqnos[REM_SEQ_COUNT]; //seqno array
u_int32_t max_seqno; //max seqno
u_int32_t min_seqno; //max seqno
u_int16_t seq_it; // seqno's iterator
};
(2)建立一个链表节点类型为MFlood_RTEntry的链表 rthead
LIST_HEAD(, MFlood_RTEntry) rthead;
(3)初始化链表rhead为NULL
LIST_INIT(&rthead)
(4) 怎样使用
MFlood_RTEntry*
MFlood_Rtable::rt_lookup(nsaddr_t id) {
Mflood_RTEntry *rt = rthead.lh_first;//获取链表表头
for(; rt; rt = rt->rt_link.le_next) {
if(rt->src_ == id)
break;
}
return rt;
}
(5)删除节点
void
MFlood_RTable::rt_delete(nsaddr_t id) {
MFlood_RTEntry *rt = rt_lookup(id);
if(rt) {
LIST_REMOVE(rt, rt_link);
delete rt;
}
}
(6)插入节点
rt = new MFlood_RTEntry(ih->saddr(), fh->seq_);
LIST_INSERT_HEAD(&rtable_.rthead,rt,rt_link);
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u1/47073/showart_1359564.html |
|