=================================
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：
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);
#endiftext.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);
#endiftest.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);
#endiftest.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;
#endiflist.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
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