数据结构day02--------单向(循环)链表、双向(循环)链表、内核链表

发布于:2023-01-22 ⋅ 阅读:(17) ⋅ 点赞:(0) ⋅ 评论:(0)

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day02--------单向(循环)链表、双向(循环)链表、内核链表

=================================

目录

数据结构

单向循环链表:

双向链表:

双向循环链表:

初始化:

插入:

剪切:

替换:

移动:

cycle_double_link(循环双向链表)

link.c

link.h

text.c

cycle_link(循环单向链表)

link.c

link.h

test.c

double_link(双向链表)

link.c

link.h

test.c

kernel(linux内核链表)

kernel.c

kernel.h

list.h



数据结构


=================================


单向循环链表:


    在单向链表基础上,最后节点的next指向头节点
    
    *优点: 插入和删除方便
    *缺点: 只能从头往后走
    
===》如何弥补单向链表的缺点:
================


双向链表:


    typedef int datatype;
    struct link{
        datatype data;            //数据域
        struct link *prev;        //指针域
        struct link *next;        //指针域
    };
    算法: 增删改查
    
===========


双向循环链表:


    最后一个节点的next 指向头 ,头的prev指向最后一个节点
    

===============================
结构体:
struct list_head{
    struct list_head *next,*prev;
};

========================


inline: 内联函数:


    可以写在头文件中的
    当别人调用该函数,它将内容全部复制过去

========================


初始化:

static inline void INIT_LIST_HEAD(struct list_head *list)
{
    list->next = list;
    list->prev = list;
}    


===============================


插入:


    
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;
}
/*********************************************
解释:
    new将prev和next链接起来 ,new在中间

*********************************************/
    
static inline void list_add(struct list_head *new, struct list_head *head)
{
    __list_add(new, head, head->next);
}
/*********************************************
解释:    
    new插在了head的后面 
    
*********************************************/
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
    __list_add(new, head->prev, head);
}
/*********************************************
解释:
    new插在了head的前面
 *********************************************/   


=============================================


剪切:


    static inline void __list_del(struct list_head * prev, struct list_head * next)
{
    next->prev = prev;
    prev->next = next;
}
/*********************************************
解释:    
    prev和next直接连接起来了
    prev在next的前面
    next在prev的后面
********************************************/ 

static inline void __list_del_entry(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
}
/*********************************************
解释:
    将entry的prev和next直接连接起来了
    将entry剪切出来了
    
 ********************************************/
static inline void list_del(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    entry->next = LIST_POISON1;
    entry->prev = LIST_POISON2;
}
#define LIST_POISON1  ((void *) 0x00100100 + 0)
#define LIST_POISON2  ((void *) 0x00200200 + 0)
    0x0804 8000
/*********************************************
解释:
    1* entry将自己剪切出来了
    2* entry->next = NULL;
    3* entry->prev = NULL;
********************************************/ 

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

解释:
    1* entry将自己剪切出来了
    2* entry自己指向自己
    
 ********************************************/   


============================================


替换:

/*********************************************
*********************************************/

    static inline void list_replace(struct list_head *old,
                struct list_head *new)
{
    new->next = old->next;
    new->next->prev = new;
    new->prev = old->prev;
    new->prev->next = new;
}
/*********************************************
解释:
    new替换了old
*********************************************/ 
    
static inline void list_replace_init(struct list_head *old,
                    struct list_head *new)
{
    list_replace(old, new);
    INIT_LIST_HEAD(old);
}
/*********************************************
解释:
    1* new替换了old
    2* old自己指向自己
*********************************************/

===========================================


移动:



    static inline void list_move(struct list_head *list, struct list_head *head)
{
    __list_del_entry(list);
    list_add(list, head);
}
/*********************************************
解释:
    1* 将list剪切出来了
    2* 将list插在head的后面
        -------》 将list移动到head的后面
        
*********************************************/    
static inline void list_move_tail(struct list_head *list,
                  struct list_head *head)
{
    __list_del_entry(list);
    list_add_tail(list, head);
}
/*********************************************
解释:
    1* 将list剪切出来了
    2* 将list插在head的前面
        -------》 将list移动到head的前面
*********************************************/    


==============================================
        

static inline int list_is_last(const struct list_head *list,
                const struct list_head *head)
{
    return list->next == head;
}
/******************************************
解释:    
    判断list是否为最后一个节点
        是返回1
        不是则返回0
******************************************/
        
static inline int list_empty(const struct list_head *head)
{
    return head->next == head;
}
/******************************************
解释:
    判断当前链表是否只有头节点

******************************************/


    

================================================
================================================
================================================

#define list_entry(ptr, type, member) \
    container_of(ptr, type, member)
    
    
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#define container_of(ptr, type, member) ({            \
    const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
    (type *)( (char *)__mptr - offsetof(type,member) );})    


/***********************************************************    
解释:
    *通过小结构体指针得到其所在的大结构体指针
    @ptr  : 外面传进来的小结构指针
    @type : 大结构的类型
    @member:小结构在大结构体中的名字

***********************************************************/
    
container_of(ptr, type, member)
    =====》
    const typeof( ((type *)0)->member ) *__mptr = (ptr);
        ----》
        const struct list_head *__mptr = (ptr); 
    
    (type *)( (char *)__mptr - offsetof(type,member) );     
        ---》通过mptr ---》 得到大结构的地址

    #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
        ====> 整除了 data所在的 字节数 (考虑对齐机制)
        

typeof() -----> 取类型

cycle_double_link(循环双向链表)

link.c

/* 双向循环链表 的  增删改查  */
#include "link.h"
#include <stdlib.h>

/**
  ***********************************
  *@brief  一个节点node插在p的后面
  *@param  p  node : 节点
  *@retval None
  ***********************************
  */
static void insert_behind(plink_t p,plink_t node)
{
	node->next = p->next;
	node->prev = p;
	p->next->prev = node;
	p->next = node;
}

/**
  ***********************************
  *@brief  一个节点node插在p的前面
  *@param  p  node : 节点
  *@retval None
  ***********************************
  */
static void insert_forward(plink_t p,plink_t node)
{
	node->next = p;
	node->prev = p->prev;
	p->prev->next = node;
	p->prev = node;
}

/**
  ***********************************
  *@brief  剪切
  *@param  node : 节点
  *@retval None
  ***********************************
  */
static void cut_node(plink_t node)
{
	node->prev->next = node->next;
	node->next->prev = node->prev;
}

/**
  ***********************************
  *@brief  new替换old
  *@param  old new 节点
  *@retval None
  ***********************************
  */
static void replace(plink_t old,plink_t new)
{
	new->next = old->next;
	new->prev = old->prev;
	new->next->prev = new;
	new->prev->next = new;
}



/**
  ***********************************
  *@brief  初始化 (创建头节点)
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_init(plink_t *p)
{
	*p=(plink_t)malloc(sizeof(link_t));
	if(*p==NULL){
		perror("malloc error");
		return;
	}
	
	(*p)->prev = (*p);
	(*p)->next = (*p);
}  

/**
  ***********************************
  *@brief  头插
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_add_head(plink_t p,datatype d)
{
	//创建新的节点
	plink_t node = NULL;
	link_init(&node);
	if(node==NULL)
		return;
	node->data = d;
	
	//将新的节点插在头的后面
	insert_behind(p,node);
}

/**
  ***********************************
  *@brief  尾插
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_add_tail(plink_t p,datatype d)
{
	//创建新的节点
	plink_t node = NULL;
	link_init(&node);
	if(node==NULL)
		return;
	node->data = d;

	//将新的节点插在头的前面
	insert_forward(p,node);
}


/**
  ***********************************
  *@brief  删除
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_del(plink_t p,datatype d)
{
	plink_t head = p;
	
	plink_t node = NULL;
	
	//找到该节点
	while(p->next!=head){
		node = p->next;
		if(node->data == d){
			
			//剪切并删除该节点
			cut_node(node);
			node->prev = node;
			node->next = node;
			free(node);
			continue;
		}
		p = p->next;
	}
}


/**
  ***********************************
  *@brief  替换
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_update(plink_t p,datatype old,datatype new)
{
	plink_t head = p;
	plink_t node = NULL;
	plink_t new_node = NULL;
	
	//遍历寻找old
	while(p->next!=head){
		node = p->next;
		if(node->data == old){
			
			//找到后,创建新的节点new
			link_init(&new_node);
			if(new_node==NULL)
				return;
			new_node->data = new;
			
			//新的节点替换old
			replace(node,new_node);
			
			//释放old
			node->prev = node;
			node->next = node;
			free(node);
		}
		
		p = p->next;
	}
}


/**
  ***********************************
  *@brief  正序遍历
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void display(plink_t p)
{
	plink_t head = p;
	
	printf("正序遍历结果为:");
	while(p->next!=head){
		p = p->next;
		printf("%d ",p->data);
	}
	printf("\n");
	
}


/**
  ***********************************
  *@brief  逆序遍历
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void pre_display(plink_t p)
{
	plink_t head = p;
	
	printf("逆序遍历结果为:");
	while(p->prev!=head){
		p = p->prev;
		printf("%d ",p->data);
	}
	printf("\n");
	
}





link.h

#ifndef __LINK_H
#define __LINK_H

#include <stdio.h>

typedef int datatype;

typedef struct link{
	datatype data;
	struct link *prev;
	struct link *next;
} link_t,*plink_t;

//      int a,b;   ---> int a;int b;
//		int a,*b;  ---> int a;int *b;
//      typedef int a;  
//		typedef int a,b;  ---> typedef int a; typedef int b;
//		typedef int a,*b; ---> typedef int a; typedef int *b;
//      typedef struct link a,*b;  ---> typedef struct link a; 
//										typedef struct link *b;

extern void link_init(plink_t *p);
extern void link_add_head(plink_t p,datatype d);
extern void link_add_tail(plink_t p,datatype d);
extern void link_del(plink_t p,datatype d);
extern void link_update(plink_t p,datatype old,datatype new);
extern void display(plink_t p);
extern void pre_display(plink_t p);

#endif

text.c


#include "link.h"

int main(void)
{
	plink_t p = NULL;
	link_init(&p);
	if(p==NULL)
		return -1;
	printf("%p\n",p);
	
	
	datatype d;
	int ret;
	printf("开始头插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_head(p,d);
		display(p);
		pre_display(p);
	}
	
	getchar();
	
	printf("开始尾插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_tail(p,d);
		display(p);
		pre_display(p);
	}

	
	getchar();
	
	printf("开始删除\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_del(p,d);
		display(p);
		pre_display(p);
	}

	getchar();
	
	
	printf("开始替换\n");
	datatype old,new;
	while(1){
		ret = scanf("%d %d",&old,&new);
		if(!ret)
			break;
		
		link_update(p,old,new);
		display(p);
		pre_display(p);
	}
	
	
	
	return 0;
}

cycle_link(循环单向链表)

link.c


#include "link.h"
#include <stdlib.h>

/* 单向链表的 增删改查 操作 */

/**
  ***********************************
  *@brief  一个节点插在另外一个节点的后面
  *@param  p  node  两个节点,node插在p的后面
  *@retval None
  ***********************************
  */
static void insert_behind(link_t *p,link_t *node)
{
	node->next = p->next;
	p->next = node;
}


/**
  ***********************************
  *@brief  将p节点的后面那个节点截切出来
  *@param  p 
  *@retval link_t *  被剪切出来的节点
  ***********************************
  */
static link_t *cut_behind(link_t *p)
{
	link_t *node = p->next;
	p->next = node->next;
	return node;
}

/**
  ***********************************
  *@brief  将p节点的后面那个节点更新为new
  *@param  p  new  2个节点
  *@retval link_t *  被替换出来的节点
  ***********************************
  */
static link_t *updata_behind(link_t *p,link_t *new)
{
	link_t *node = p->next;
	
	new->next = node->next;
	p->next = new;
	
	return node;
}


/**
  ***********************************
  *@brief  初始化 (创建头节点)
  *@param  None
  *@retval link_t * :
  *				成功返回地址
  *				失败返回NULL
  ***********************************
  */
link_t *link_init(void)
{
	link_t *p = (link_t *)malloc(sizeof(link_t));
	if(p==NULL){
		perror("malloc error");
		return NULL;
	}
	
	p->next = p;  //自己指向自己
	
	return p;
}

/**
  ***********************************
  *@brief  插入_头插
  *@param  p : 头节点
  *@param  d : 需要插入的数据 
  *@retval None;
  ***********************************
  */
void link_add_head(link_t *p,datatype d)
{
	//创建新的节点
	link_t *node = link_init();
	if(node==NULL){
		printf("创建新节点失败\n");
		return;
	}
	node->data = d;

	//将新的节点插在头的后面
	insert_behind(p,node);
}

/**
  ***********************************
  *@brief  插入_尾插
  *@param  p : 头节点
  *@param  d : 需要插入的数据 
  *@retval None
  ***********************************
  */
void link_add_tail(link_t *p,datatype d)
{
	//保存头节点
	link_t *head = p;
	
	//创建新的节点
	link_t *node = link_init();
	if(node==NULL){
		printf("创建新节点失败\n");
		return;
	}
	node->data = d;
	
	//找到最后一个节点
	while(p->next!=head)
		p = p->next;

	//将新的节点插在尾巴的后面
	insert_behind(p,node);
}

/**
  ***********************************
  *@brief  删除
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_del(link_t *p,datatype d)
{
	//保存头节点
	link_t *head = p;
	
	link_t *node = NULL;
	
	while(p->next!=head){
		if(p->next->data==d){
			node = cut_behind(p);
			
			node->next = node;  //保证安全
			free(node);
			continue;
		}
		p = p->next;
	}
}


/**
  ***********************************
  *@brief  修改
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_update(link_t *p,datatype old,datatype new)
{
	//保存头节点
	link_t *head = p;
	
	link_t *new_node = NULL;
	link_t *old_node = NULL;
	
	//遍历查询old
	while(p->next!=head){
		if(p->next->data == old){
			
			//通过new 创建新的节点
			new_node = link_init();
			if(new_node==NULL){
				printf("创建新节点失败\n");
				return;
			}
			new_node->data = new;
			
			// new节点替换old
			old_node = updata_behind(p,new_node);
			
			// 将old节点释放
			old_node->next = old_node;
			free(old_node);
		}
		p = p->next;
	}
	
}


/**
  ***********************************
  *@brief  遍历
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void display(link_t *p)
{
	//保存头节点
	link_t *head = p;
	
	printf("遍历结果为:");
	while(p->next!=head){
		p = p->next;
		printf("%d ",p->data);
	}
	printf("\n");
}



link.h

#ifndef __LINK_H
#define __LINK_H

#include <stdio.h>

typedef int datatype;

typedef struct link{
	datatype data;			//数据域
	struct link *next;		//指针域
} link_t;


extern link_t *link_init(void);
extern void link_add_head(link_t *p,datatype d);
extern void link_add_tail(link_t *p,datatype d);
extern void link_del(link_t *p,datatype d);
extern void link_update(link_t *p,datatype old,datatype new);
extern void display(link_t *p);

#endif

test.c


#include "link.h"


int main(void)
{
	//初始化
	link_t * p  = link_init();
	if(p==NULL)
		return -1;
	printf("%p\n",p);
	
	datatype d;
	int ret;
	
	printf("开始头插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_head(p,d);
		display(p);
	}
	
	getchar();
	
	printf("开始尾插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_tail(p,d);
		display(p);
	}
	
	getchar();
	
	printf("开始删除\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_del(p,d);
		display(p);
	}
	
	getchar();
	
	
	printf("开始替换\n");
	datatype old,new;
	while(1){
		ret = scanf("%d %d",&old,&new);
		if(!ret)
			break;
		
		link_update(p,old,new);
		display(p);
	}
	
	
	
}

double_link(双向链表)

link.c

/* 双向链表 的  增删改查  */
#include "link.h"
#include <stdlib.h>

/**
  ***********************************
  *@brief  一个节点node插在p的后面
  *@param  p  node : 节点
  *@retval None
  ***********************************
  */
static void insert_behind(plink_t p,plink_t node)
{
	node->next = p->next;
	node->prev = p;
	if(p->next!=NULL)
		p->next->prev = node;
	p->next = node;
}

/**
  ***********************************
  *@brief  剪切
  *@param  node : 节点
  *@retval None
  ***********************************
  */
static void cut_node(plink_t node)
{
	node->prev->next = node->next;
	if(node->next!=NULL)
		node->next->prev = node->prev;
}

/**
  ***********************************
  *@brief  new替换old
  *@param  old new 节点
  *@retval None
  ***********************************
  */
static void replace(plink_t old,plink_t new)
{
	new->next = old->next;
	new->prev = old->prev;
	if(new->next!=NULL)
		new->next->prev = new;
	new->prev->next = new;
}



/**
  ***********************************
  *@brief  初始化 (创建头节点)
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_init(plink_t *p)
{
	*p=(plink_t)malloc(sizeof(link_t));
	if(*p==NULL){
		perror("malloc error");
		return;
	}
	
	(*p)->prev = NULL;
	(*p)->next = NULL;
}  

/**
  ***********************************
  *@brief  头插
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_add_head(plink_t p,datatype d)
{
	//创建新的节点
	plink_t node = NULL;
	link_init(&node);
	if(node==NULL)
		return;
	node->data = d;
	
	//将新的节点插在头的后面
	insert_behind(p,node);
}

/**
  ***********************************
  *@brief  尾插
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void link_add_tail(plink_t p,datatype d)
{
	//创建新的节点
	plink_t node = NULL;
	link_init(&node);
	if(node==NULL)
		return;
	node->data = d;
	
	//跳到尾巴上
	while(p->next!=NULL)
		p = p->next;
	
	//将新的节点插在尾巴的后面
	insert_behind(p,node);
}


/**
  ***********************************
  *@brief  删除
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_del(plink_t p,datatype d)
{
	plink_t node = NULL;
	
	//找到该节点
	while(p->next!=NULL){
		node = p->next;
		if(node->data == d){
			
			//剪切并删除该节点
			cut_node(node);
			node->prev = NULL;
			node->next = NULL;
			free(node);
			continue;
		}
		p = p->next;
	}
}


/**
  ***********************************
  *@brief  替换
  *@param  p : 头节点
  *@param  d : 需要删除的数据
  *@retval None
  ***********************************
  */
void link_update(plink_t p,datatype old,datatype new)
{
	plink_t node = NULL;
	plink_t new_node = NULL;
	
	//遍历寻找old
	while(p->next!=NULL){
		node = p->next;
		if(node->data == old){
			
			//找到后,创建新的节点new
			link_init(&new_node);
			if(new_node==NULL)
				return;
			new_node->data = new;
			
			//新的节点替换old
			replace(node,new_node);
			
			//释放old
			node->prev = NULL;
			node->next = NULL;
			free(node);
		}
		
		p = p->next;
	}
}


/**
  ***********************************
  *@brief  遍历
  *@param  p : 头节点
  *@retval None
  ***********************************
  */
void display(plink_t p)
{
	printf("遍历结果为:");
	while(p->next!=NULL){
		p = p->next;
		printf("%d ",p->data);
	}
	printf("\n");
	
}





link.h

#ifndef __LINK_H
#define __LINK_H

#include <stdio.h>

typedef int datatype;

typedef struct link{
	datatype data;
	struct link *prev;
	struct link *next;
} link_t,*plink_t;

//      int a,b;   ---> int a;int b;
//		int a,*b;  ---> int a;int *b;
//      typedef int a;  
//		typedef int a,b;  ---> typedef int a; typedef int b;
//		typedef int a,*b; ---> typedef int a; typedef int *b;
//      typedef struct link a,*b;  ---> typedef struct link a; 
//										typedef struct link *b;

extern void link_init(plink_t *p);
extern void link_add_head(plink_t p,datatype d);
extern void link_add_tail(plink_t p,datatype d);
extern void link_del(plink_t p,datatype d);
extern void link_update(plink_t p,datatype old,datatype new);
extern void display(plink_t p);

#endif

test.c


#include "link.h"

int main(void)
{
	plink_t p = NULL;
	link_init(&p);
	if(p==NULL)
		return -1;
	printf("%p\n",p);
	
	
	datatype d;
	int ret;
	printf("开始头插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_head(p,d);
		display(p);
	}
	
	getchar();
	
	printf("开始尾插\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_add_tail(p,d);
		display(p);
	}

	
	getchar();
	
	printf("开始删除\n");
	while(1){
		ret = scanf("%d",&d);
		if(!ret)
			break;
		
		link_del(p,d);
		display(p);
	}

	getchar();
	
	
	printf("开始替换\n");
	datatype old,new;
	while(1){
		ret = scanf("%d %d",&old,&new);
		if(!ret)
			break;
		
		link_update(p,old,new);
		display(p);
	}
	
	
	
	return 0;
}

kernel(linux内核链表)

kernel.c


/* 内核链表的 增删改查操作 */
#include "kernel.h"


/**
  ***********************************
  *@brief  初始化
  *@param  p  node : 节点
  *@retval None
  ***********************************
  */
void kernel_init(pkernel_t *p)
{
	*p = (pkernel_t)malloc(sizeof(kernel_t));
	if(*p==NULL){
		perror("malloc error");
		return;
	}
	
	INIT_LIST_HEAD(&(*p)->list);
}

kernel.h

#ifndef __KERNEL_H
#define __KERNEL_H

#include <stdio.h>
#include "list.h"


typedef int datatype;

typedef struct kernel{
	datatype data;
	struct list_head list;
} kernel_t,*pkernel_t;




#endif

list.h

#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H

/*
 * Simple doubly linked list implementation.
 *
 * Some of the internal functions ("__xxx") are useful when
 * manipulating whole lists rather than single entries, as
 * sometimes we already know the next/prev entries and we can
 * generate better code by using them directly rather than
 * using the generic single-entry routines.
 */

struct list_head{
	struct list_head *next,*prev;
};

#define LIST_POISON1  ((void *) 0x00100100 + 0)
#define LIST_POISON2  ((void *) 0x00200200 + 0)

#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#define container_of(ptr, type, member) ({			\
	const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
	(type *)( (char *)__mptr - offsetof(type,member) );})


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

#define LIST_HEAD(name) \
	struct list_head name = LIST_HEAD_INIT(name)

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	list->next = list;
	list->prev = list;
}

/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
#ifndef CONFIG_DEBUG_LIST
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;
}
#else
extern void __list_add(struct list_head *new,
			      struct list_head *prev,
			      struct list_head *next);
#endif

/**
 * list_add - add a new entry
 * @new: new entry to be added
 * @head: list head to add it after
 *
 * Insert a new entry after the specified head.
 * This is good for implementing stacks.
 */
static inline void list_add(struct list_head *new, struct list_head *head)
{
	__list_add(new, head, head->next);
}


/**
 * list_add_tail - add a new entry
 * @new: new entry to be added
 * @head: list head to add it before
 *
 * Insert a new entry before the specified head.
 * This is useful for implementing queues.
 */
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
	__list_add(new, head->prev, head);
}

/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
	next->prev = prev;
	prev->next = next;
}

/**
 * list_del - deletes entry from list.
 * @entry: the element to delete from the list.
 * Note: list_empty() on entry does not return true after this, the entry is
 * in an undefined state.
 */
#ifndef CONFIG_DEBUG_LIST
static inline void __list_del_entry(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
}

static inline void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	entry->next = LIST_POISON1;
	entry->prev = LIST_POISON2;
}
#else
extern void __list_del_entry(struct list_head *entry);
extern void list_del(struct list_head *entry);
#endif

/**
 * list_replace - replace old entry by new one
 * @old : the element to be replaced
 * @new : the new element to insert
 *
 * If @old was empty, it will be overwritten.
 */
static inline void list_replace(struct list_head *old,
				struct list_head *new)
{
	new->next = old->next;
	new->next->prev = new;
	new->prev = old->prev;
	new->prev->next = new;
}

static inline void list_replace_init(struct list_head *old,
					struct list_head *new)
{
	list_replace(old, new);
	INIT_LIST_HEAD(old);
}

/**
 * list_del_init - deletes entry from list and reinitialize it.
 * @entry: the element to delete from the list.
 */
static inline void list_del_init(struct list_head *entry)
{
	__list_del_entry(entry);
	INIT_LIST_HEAD(entry);
}

/**
 * list_move - delete from one list and add as another's head
 * @list: the entry to move
 * @head: the head that will precede our entry
 */
static inline void list_move(struct list_head *list, struct list_head *head)
{
	__list_del_entry(list);
	list_add(list, head);
}

/**
 * list_move_tail - delete from one list and add as another's tail
 * @list: the entry to move
 * @head: the head that will follow our entry
 */
static inline void list_move_tail(struct list_head *list,
				  struct list_head *head)
{
	__list_del_entry(list);
	list_add_tail(list, head);
}

/**
 * list_is_last - tests whether @list is the last entry in list @head
 * @list: the entry to test
 * @head: the head of the list
 */
static inline int list_is_last(const struct list_head *list,
				const struct list_head *head)
{
	return list->next == head;
}

/**
 * list_empty - tests whether a list is empty
 * @head: the list to test.
 */
static inline int list_empty(const struct list_head *head)
{
	return head->next == head;
}

/**
 * list_empty_careful - tests whether a list is empty and not being modified
 * @head: the list to test
 *
 * Description:
 * tests whether a list is empty _and_ checks that no other CPU might be
 * in the process of modifying either member (next or prev)
 *
 * NOTE: using list_empty_careful() without synchronization
 * can only be safe if the only activity that can happen
 * to the list entry is list_del_init(). Eg. it cannot be used
 * if another CPU could re-list_add() it.
 */
static inline int list_empty_careful(const struct list_head *head)
{
	struct list_head *next = head->next;
	return (next == head) && (next == head->prev);
}

/**
 * list_rotate_left - rotate the list to the left
 * @head: the head of the list
 */
static inline void list_rotate_left(struct list_head *head)
{
	struct list_head *first;

	if (!list_empty(head)) {
		first = head->next;
		list_move_tail(first, head);
	}
}

/**
 * list_is_singular - tests whether a list has just one entry.
 * @head: the list to test.
 */
static inline int list_is_singular(const struct list_head *head)
{
	return !list_empty(head) && (head->next == head->prev);
}

static inline void __list_cut_position(struct list_head *list,
		struct list_head *head, struct list_head *entry)
{
	struct list_head *new_first = entry->next;
	list->next = head->next;
	list->next->prev = list;
	list->prev = entry;
	entry->next = list;
	head->next = new_first;
	new_first->prev = head;
}

/**
 * list_cut_position - cut a list into two
 * @list: a new list to add all removed entries
 * @head: a list with entries
 * @entry: an entry within head, could be the head itself
 *	and if so we won't cut the list
 *
 * This helper moves the initial part of @head, up to and
 * including @entry, from @head to @list. You should
 * pass on @entry an element you know is on @head. @list
 * should be an empty list or a list you do not care about
 * losing its data.
 *
 */
static inline void list_cut_position(struct list_head *list,
		struct list_head *head, struct list_head *entry)
{
	if (list_empty(head))
		return;
	if (list_is_singular(head) &&
		(head->next != entry && head != entry))
		return;
	if (entry == head)
		INIT_LIST_HEAD(list);
	else
		__list_cut_position(list, head, entry);
}

static inline void __list_splice(const struct list_head *list,
				 struct list_head *prev,
				 struct list_head *next)
{
	struct list_head *first = list->next;
	struct list_head *last = list->prev;

	first->prev = prev;
	prev->next = first;

	last->next = next;
	next->prev = last;
}

/**
 * list_splice - join two lists, this is designed for stacks
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice(const struct list_head *list,
				struct list_head *head)
{
	if (!list_empty(list))
		__list_splice(list, head, head->next);
}

/**
 * list_splice_tail - join two lists, each list being a queue
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice_tail(struct list_head *list,
				struct list_head *head)
{
	if (!list_empty(list))
		__list_splice(list, head->prev, head);
}

/**
 * list_splice_init - join two lists and reinitialise the emptied list.
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * The list at @list is reinitialised
 */
static inline void list_splice_init(struct list_head *list,
				    struct list_head *head)
{
	if (!list_empty(list)) {
		__list_splice(list, head, head->next);
		INIT_LIST_HEAD(list);
	}
}

/**
 * list_splice_tail_init - join two lists and reinitialise the emptied list
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * Each of the lists is a queue.
 * The list at @list is reinitialised
 */
static inline void list_splice_tail_init(struct list_head *list,
					 struct list_head *head)
{
	if (!list_empty(list)) {
		__list_splice(list, head->prev, head);
		INIT_LIST_HEAD(list);
	}
}

/**
 * list_entry - get the struct for this entry
 * @ptr:	the &struct list_head pointer.
 * @type:	the type of the struct this is embedded in.
 * @member:	the name of the list_struct within the struct.
 */
#define list_entry(ptr, type, member) \
	container_of(ptr, type, member)

/**
 * list_first_entry - get the first element from a list
 * @ptr:	the list head to take the element from.
 * @type:	the type of the struct this is embedded in.
 * @member:	the name of the list_struct within the struct.
 *
 * Note, that list is expected to be not empty.
 */
#define list_first_entry(ptr, type, member) \
	list_entry((ptr)->next, type, member)

/**
 * list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 */
#define list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); pos = pos->next)

/**
 * __list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 *
 * This variant doesn't differ from list_for_each() any more.
 * We don't do prefetching in either case.
 */
#define __list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); pos = pos->next)

/**
 * list_for_each_prev	-	iterate over a list backwards
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 */
#define list_for_each_prev(pos, head) \
	for (pos = (head)->prev; pos != (head); pos = pos->prev)

/**
 * list_for_each_safe - iterate over a list safe against removal of list entry
 * @pos:	the &struct list_head to use as a loop cursor.
 * @n:		another &struct list_head to use as temporary storage
 * @head:	the head for your list.
 */
#define list_for_each_safe(pos, n, head) \
	for (pos = (head)->next, n = pos->next; pos != (head); \
		pos = n, n = pos->next)

/**
 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
 * @pos:	the &struct list_head to use as a loop cursor.
 * @n:		another &struct list_head to use as temporary storage
 * @head:	the head for your list.
 */
#define list_for_each_prev_safe(pos, n, head) \
	for (pos = (head)->prev, n = pos->prev; \
	     pos != (head); \
	     pos = n, n = pos->prev)

/**
 * list_for_each_entry	-	iterate over list of given type
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry(pos, head, member)				\
	for (pos = list_entry((head)->next, typeof(*pos), member);	\
	     &pos->member != (head); 	\
	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_reverse - iterate backwards over list of given type.
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry_reverse(pos, head, member)			\
	for (pos = list_entry((head)->prev, typeof(*pos), member);	\
	     &pos->member != (head); 	\
	     pos = list_entry(pos->member.prev, typeof(*pos), member))

/**
 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
 * @pos:	the type * to use as a start point
 * @head:	the head of the list
 * @member:	the name of the list_struct within the struct.
 *
 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
 */
#define list_prepare_entry(pos, head, member) \
	((pos) ? : list_entry(head, typeof(*pos), member))

/**
 * list_for_each_entry_continue - continue iteration over list of given type
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Continue to iterate over list of given type, continuing after
 * the current position.
 */
#define list_for_each_entry_continue(pos, head, member) 		\
	for (pos = list_entry(pos->member.next, typeof(*pos), member);	\
	     &pos->member != (head);	\
	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_continue_reverse - iterate backwards from the given point
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Start to iterate over list of given type backwards, continuing after
 * the current position.
 */
#define list_for_each_entry_continue_reverse(pos, head, member)		\
	for (pos = list_entry(pos->member.prev, typeof(*pos), member);	\
	     &pos->member != (head);	\
	     pos = list_entry(pos->member.prev, typeof(*pos), member))

/**
 * list_for_each_entry_from - iterate over list of given type from the current point
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type, continuing from current position.
 */
#define list_for_each_entry_from(pos, head, member) 			\
	for (; &pos->member != (head);	\
	     pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry_safe(pos, n, head, member)			\
	for (pos = list_entry((head)->next, typeof(*pos), member),	\
		n = list_entry(pos->member.next, typeof(*pos), member);	\
	     &pos->member != (head); 					\
	     pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_continue - continue list iteration safe against removal
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type, continuing after current point,
 * safe against removal of list entry.
 */
#define list_for_each_entry_safe_continue(pos, n, head, member) 		\
	for (pos = list_entry(pos->member.next, typeof(*pos), member), 		\
		n = list_entry(pos->member.next, typeof(*pos), member);		\
	     &pos->member != (head);						\
	     pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_from - iterate over list from current point safe against removal
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type from current point, safe against
 * removal of list entry.
 */
#define list_for_each_entry_safe_from(pos, n, head, member) 			\
	for (n = list_entry(pos->member.next, typeof(*pos), member);		\
	     &pos->member != (head);						\
	     pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate backwards over list of given type, safe against removal
 * of list entry.
 */
#define list_for_each_entry_safe_reverse(pos, n, head, member)		\
	for (pos = list_entry((head)->prev, typeof(*pos), member),	\
		n = list_entry(pos->member.prev, typeof(*pos), member);	\
	     &pos->member != (head); 					\
	     pos = n, n = list_entry(n->member.prev, typeof(*n), member))

/**
 * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
 * @pos:	the loop cursor used in the list_for_each_entry_safe loop
 * @n:		temporary storage used in list_for_each_entry_safe
 * @member:	the name of the list_struct within the struct.
 *
 * list_safe_reset_next is not safe to use in general if the list may be
 * modified concurrently (eg. the lock is dropped in the loop body). An
 * exception to this is if the cursor element (pos) is pinned in the list,
 * and list_safe_reset_next is called after re-taking the lock and before
 * completing the current iteration of the loop body.
 */
#define list_safe_reset_next(pos, n, member)				\
	n = list_entry(pos->member.next, typeof(*pos), member)

/*
 * Double linked lists with a single pointer list head.
 * Mostly useful for hash tables where the two pointer list head is
 * too wasteful.
 * You lose the ability to access the tail in O(1).
 */
#endif