从libuv中提取出来的双循环链表
就一个文件：
/* Copyright (c) 2013, Ben Noordhuis
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef QUEUE_H_
#define QUEUE_H_
#include
typedef void *QUEUE[2];
/* Private macros. */
#define QUEUE_NEXT(q) (*(QUEUE **) &((*(q))[0]))
#define QUEUE_PREV(q) (*(QUEUE **) &((*(q))[1]))
#define QUEUE_PREV_NEXT(q) (QUEUE_NEXT(QUEUE_PREV(q)))
#define QUEUE_NEXT_PREV(q) (QUEUE_PREV(QUEUE_NEXT(q)))
/* Public macros. */
#define QUEUE_DATA(ptr, type, field) \
((type *) ((char *) (ptr) - offsetof(type, field)))
/* Important note: mutating the list while QUEUE_FOREACH is
* iterating over its elements results in undefined behavior.
*/
#define QUEUE_FOREACH(q, h) \
for ((q) = QUEUE_NEXT(h); (q) != (h); (q) = QUEUE_NEXT(q))
#define QUEUE_EMPTY(q) \
((const QUEUE *) (q) == (const QUEUE *) QUEUE_NEXT(q))
#define QUEUE_HEAD(q) \
(QUEUE_NEXT(q))
#define QUEUE_INIT(q) \
do { \
QUEUE_NEXT(q) = (q); \
QUEUE_PREV(q) = (q); \
} \
while (0)
#define QUEUE_ADD(h, n) \
do { \
QUEUE_PREV_NEXT(h) = QUEUE_NEXT(n); \
QUEUE_NEXT_PREV(n) = QUEUE_PREV(h); \
QUEUE_PREV(h) = QUEUE_PREV(n); \
QUEUE_PREV_NEXT(h) = (h); \
} \
while (0)
#define QUEUE_SPLIT(h, q, n) \
do { \
QUEUE_PREV(n) = QUEUE_PREV(h); \
QUEUE_PREV_NEXT(n) = (n); \
QUEUE_NEXT(n) = (q); \
QUEUE_PREV(h) = QUEUE_PREV(q); \
QUEUE_PREV_NEXT(h) = (h); \
QUEUE_PREV(q) = (n); \
} \
while (0)
#define QUEUE_MOVE(h, n) \
do { \
if (QUEUE_EMPTY(h)) \
QUEUE_INIT(n); \
else { \
QUEUE* q = QUEUE_HEAD(h); \
QUEUE_SPLIT(h, q, n); \
} \
} \
while (0)
#define QUEUE_INSERT_HEAD(h, q) \
do { \
QUEUE_NEXT(q) = QUEUE_NEXT(h); \
QUEUE_PREV(q) = (h); \
QUEUE_NEXT_PREV(q) = (q); \
QUEUE_NEXT(h) = (q); \
} \
while (0)
#define QUEUE_INSERT_TAIL(h, q) \
do { \
QUEUE_NEXT(q) = (h); \
QUEUE_PREV(q) = QUEUE_PREV(h); \
QUEUE_PREV_NEXT(q) = (q); \
QUEUE_PREV(h) = (q); \
} \
while (0)
#define QUEUE_REMOVE(q) \
do { \
QUEUE_PREV_NEXT(q) = QUEUE_NEXT(q); \
QUEUE_NEXT_PREV(q) = QUEUE_PREV(q); \
} \
while (0)
#endif /* QUEUE_H_ */
其中#include
这个链表需要一个固定表头，和我一般理解的双循环链表任何node都可以当表头不同。当然你也可以这么改造一下也很简单。
示例代码:
#include "queue.h"
#include
static QUEUE* q;
static QUEUE queue;//定义一个双循环链表
struct user_s {
int age;
char* name;
QUEUE node;
};
void CtestDlgDlg::OnBnClickedButton1()
{
struct user_s* user;
struct user_s john;
struct user_s henry;
john.name = "john";
john.age = 44;
henry.name = "henry";
henry.age = 32;
//QUEUE_INIT的工作就是把每个node的前后指针都指向自己
QUEUE_INIT(&queue);
QUEUE_INIT(&john.node);
QUEUE_INIT(&henry.node);
//给尾部添加一个元素，如果是空链表，那么queue的前后都指向自己
QUEUE_INSERT_TAIL(&queue, &john.node);
QUEUE_INSERT_TAIL(&queue, &henry.node);
q = QUEUE_HEAD(&queue);
//根据偏移找到node的父结构体指针，因此承载链表的node，必须定义在每个结构体的最后一个元素，否则偏移就会出错
user = QUEUE_DATA(q, struct user_s, node);
printf("Received first inserted user: %s who is %d.\n",
user->name, user->age);
QUEUE_REMOVE(q);
//遍历每个node 虽然这个链表有三个node 这里自动跳过了head
QUEUE_FOREACH(q, &queue) {
user = QUEUE_DATA(q, struct user_s, node);
printf("Received rest inserted users: %s who is %d.\n",
user->name, user->age);
}
return ;
}