kernel 中链表的简单应用

直接上代码:

我这是从list.h中摘出来的,编译测试通过!

#ifndef _LIST_H_
#define _LIST_H_

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

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

#define LIST_HEAD_INIT(name) {&(name), &(name)}
#define LIST_HEAD(name) \
	struct list_head name = LIST_HEAD_INIT(name)


#if 1
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!
 */
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;
}

/**
 * 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.
 */
void list_add(struct list_head *new, struct list_head *head)
{
	__list_add(new, head, head->next);
}

/*
 * 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.
 */
void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	entry->next = LIST_POISON1;
	entry->prev = LIST_POISON2;
}

/**
 * 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)


/* from kernel.h */
#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) );})


/**
 * 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)

#endif
#endif

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

struct my_struct {
	struct list_head list;
	char name[16];
	int money;
};

int main(void)
{
	struct my_struct head = {
		.list = LIST_HEAD_INIT(head.list),
		.name = "boss",
		.money = 100
	};

	struct my_struct *james = (struct my_struct *)malloc(sizeof(struct my_struct));
	struct my_struct *linda = (struct my_struct *)malloc(sizeof(struct my_struct));
	struct my_struct *alex = (struct my_struct *)malloc(sizeof(struct my_struct));

	strcpy(james->name,  "james");
	james->money = 20000;

	strcpy(linda->name,  "linda");
	linda->money = 30000;

	strcpy(alex->name,  "alex");
	alex->money = 40000;

	list_add(&james->list, &head.list);
	list_add(&linda->list, &james->list);
	list_add(&alex->list, &linda->list);

	struct list_head *p, *n;
	struct my_struct *out;

	list_for_each_safe(p, n, &head.list){
		out = list_entry(p, struct my_struct, list);	
		printf("%s:money=%d\n", out->name, out->money);
		if(strcmp(out->name, "james") == 0){
			list_del(&out->list);
			free(out);
		}
	}
	
	printf("del one\n");
	list_for_each_safe(p, n, &head.list){
		out = list_entry(p, struct my_struct, list);	
		printf("%s:money=%d\n", out->name, out->money);
	}
	return 0;
}


编译执行:

gcc main.c

./a.out


运行效果:

james:money=20000
linda:money=30000
alex:money=40000
del one
linda:money=30000
alex:money=40000







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