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现任职北京某互联网公司运维经理,高级架构师,涉足互联网运维行业已经超过10年。曾服务于京东商城,互动百科等互联网公司,早期运维界新星。 长期专研,C语言开发,操作系统内核,大型互联网架构。http://www.bdkyr.com

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分类: 系统运维

2015-02-12 14:20:48

      上篇博文《linux内核源码“双向链表list_head”》中以一个实例介绍了list_head双向链表的用法,只有实例的代码,并没有list_head链表的代码,考虑到各位好学博友的强烈愿望,今天把list_head的代码即list.h头文件粘贴到此,供各位好学博友使用。

一、list.h头文件源码
[root@bdkyr cstudy]# cat list.h             #list.h头文件
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H

#include

#undef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif

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

/*
 * 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 FLIST_HEAD_INIT(name) { &(name), &(name) }

#define FLIST_HEAD(name) \
        struct list_head name = FLIST_HEAD_INIT(name)

#define INIT_LIST_HEAD(ptr) do { \
        (ptr)->next = (ptr); (ptr)->prev = (ptr); \
} while (0)

/*
 * 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_entry,
                               struct list_head *prev,
                               struct list_head *next)
{
        next->prev = new_entry;
        new_entry->next = next;
        new_entry->prev = prev;
        prev->next = new_entry;
}

/**
 * list_add - add a new entry
 * @new_entry: 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_entry,
                             struct list_head *head)
{
        __list_add(new_entry, head, head->next);
}

static inline void list_add_tail(struct list_head *new_entry,
                                  struct list_head *head)
{
        __list_add(new_entry, 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.
 */
static inline void list_del(struct list_head *entry)
{
        __list_del(entry->prev, entry->next);
        entry->next = NULL;
        entry->prev = NULL;
}

/**
 * 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->prev, entry->next);
        INIT_LIST_HEAD(entry);
}

/**
 * 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;
}

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;
}

static inline void list_splice(const struct list_head *list,
                                struct list_head *head)
{
        if (!list_empty(list))
                __list_splice(list, head, head->next);
}

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

/**
 * list_for_each_safe   -       iterate over a list safe against removal of list entry
 * @pos:        the &struct list_head to use as a loop counter.
 * @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)

extern void list_sort(void *priv, struct list_head *head,
        int (*cmp)(void *priv, struct list_head *a, struct list_head *b));

#endif

二、编译double_list.c
[root@bdkyr cstudy]# gcc double_list.c -o double_list

三、运行
[root@bdkyr cstudy]# ./double_list                   
************遍历链表,打印结果**************
val = 1, num = 1
val = 2, num = 2
val = 3, num = 3
************删除节点b,重新遍历链表,打印结果*
val = 1, num = 1
val = 3, num = 3
************打印链表head1******************
val = 4, num = 4
val = 5, num = 5
*******************************************
the list is not empty!

如果博友觉得这个链表不错,可以参考测试实例,编写适合自己业务应用的代码,谢谢!
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