cugb_cat
从2.6.11内核中提取出来的双向循环链表
双向循环链表，保存到一个头文件中即可
[code]
#ifndef __KERNEL_LIST_H__
#define __KERNEL_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.
*/
#include <stddef.h>
struct list_head {
struct list_head *next, *prev;
};
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) /
struct list_head name = LIST_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,
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.
*/
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.
*/
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_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(list->prev, list->next);
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(list->prev, list->next);
list_add_tail(list, 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_ checks that no other CPU might be
* in the process of still modifying either member
*
* 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.
*
* @head: the list to test.
*/
static inline int list_empty_careful(const struct list_head *head)
{
struct list_head *next = head->next;
return (next == head) && (next == head->prev);
}
static inline void __list_splice(struct list_head *list,
struct list_head *head)
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
struct list_head *at = head->next;
first->prev = head;
head->next = first;
last->next = at;
at->prev = last;
}
/**
* list_splice - join two lists
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
static inline void list_splice(struct list_head *list, struct list_head *head)
{
if (!list_empty(list))
__list_splice(list, 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);
INIT_LIST_HEAD(list);
}
}
//#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
/**
* container_of - cast a member of a structure out to the containing structure
*
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
* @member: the name of the member within the struct.
*
*/
#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)
/**
* 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 - iterate over a list
* @pos: the &struct list_head to use as a loop counter.
* @head: the head for your list.
*
* This variant differs from list_for_each() in that it's the
* simplest possible list iteration code, no prefetching is done.
* Use this for code that knows the list to be very short (empty
* or 1 entry) most of the time.
*/
#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 counter.
* @head: the head for your list.
*/
#define list_for_each_prev(pos, head) /
for (pos = (head)->prev; prefetch(pos->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 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)
/**
* list_for_each_entry - iterate over list of given type
* @pos: the type * to use as a loop counter.
* @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); /
prefetch(pos->member.next), &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 counter.
* @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); /
prefetch(pos->member.prev), &pos->member != (head); /
pos = list_entry(pos->member.prev, typeof(*pos), member))
/**
* list_prepare_entry - prepare a pos entry for use as a start point 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.
*/
#define list_prepare_entry(pos, head, member) /
((pos) ? : list_entry(head, typeof(*pos), member))
/**
* list_for_each_entry_continue - iterate over list of given type
* continuing after existing point
* @pos: the type * to use as a loop counter.
* @head: the head for your list.
* @member: the name of the list_struct within the struct.
*/
#define list_for_each_entry_continue(pos, head, member) /
for (pos = list_entry(pos->member.next, typeof(*pos), member); /
prefetch(pos->member.next), &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 counter.
* @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))
#endif
[/code]
使用该链表的示例程序如下：
[code]
#include <stdio.h>
#include <stdlib.h>
#include "kernel_list.h"
typedef struct test_struct
{
int test_a;
char test_b;
struct list_head list;
}TEST_LIST;
int main(int argc, char *argv[])
{
TEST_LIST *p = NULL;
struct list_head *ptr = NULL;
LIST_HEAD(list);
int i;
for (i = 0; i < 10; i++) {
p = (TEST_LIST *)malloc(sizeof(TEST_LIST));
p->test_a = i;
p->test_b = i + 1;
list_add(&(p->list), &list);
}
list_for_each(ptr, &list) {
p = list_entry(ptr, TEST_LIST, list);
printf("%d %d/n", p->test_a, p->test_b);
}
return 0;
}
[/code]
更多的使用方法见：[url]http://www.ibm.com/developerworks/cn/linux/kernel/l-chain/index.html[/url]
hiwoody
在分析LINUX KERNEL中TCP/IP模块的时候碰到过
构造sock那一部分
cugb_cat
[quote]原帖由 [i]hiwoody[/i] 于 2008-2-16 11:03 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7966618&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
在分析LINUX KERNEL中TCP/IP模块的时候碰到过
构造sock那一部分 [/quote]
很多都用这个接口，进程描述符、netfilter中也都是用这个。
RobinsonNie
注意可移植性(typeof是GCC扩展).
注意展开后的代码密度.
[[i] 本帖最后由 RobinsonNie 于 2008-2-17 23:46 编辑 [/i]]
cugb_cat
[quote]原帖由 [i]RobinsonNie[/i] 于 2008-2-17 23:44 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7971070&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
注意可移植性(typeof是GCC扩展).
注意展开后的代码密度. [/quote]
恩，移植性不太好，呵呵，不过在Linux下用已经没问题了。
代码密度，应该不会太大吧，这是内核中代码，我没怎么改动，只是合并了一些，删除了一些。
RobinsonNie
[quote]原帖由 [i]cugb_cat[/i] 于 2008-2-17 23:58 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7971103&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
恩，移植性不太好，呵呵，不过在Linux下用已经没问题了。
代码密度，应该不会太大吧，这是内核中代码，我没怎么改动，只是合并了一些，删除了一些。 [/quote]
busybox中有一套封装的常用系统调用的库,经过多年考验.也可以像斑竹一样拿来主义,自己写的总是有一小点不放心.
顺便恭喜cugb_cat上任滴新斑竹...:em04: :em04: :em04:
cugb_cat
[quote]原帖由 [i]RobinsonNie[/i] 于 2008-2-18 00:18 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7971156&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
busybox中有一套封装的常用系统调用的库,经过多年考验.也可以像斑竹一样拿来主义,自己写的总是有一小点不放心.
顺便恭喜cugb_cat上任滴新斑竹...:em04: :em04: :em04: [/quote]
谢谢。
SST中国
哎,很多GCC扩展,移植到windows上会有问题.
cugb_cat
[quote]原帖由 [i]SST中国[/i] 于 2008-2-18 10:10 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7971563&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
哎,很多GCC扩展,移植到windows上会有问题. [/quote]
Linux内核中使用GCC扩展还是很平常的。
想飞的蜗牛
:mrgreen: thx
搜贴的时候搜过思版的一篇文章，比较类似
[url]http://bbs.chinaunix.net/viewthread.php?tid=941100&highlight=%CB%BC%D2%BB%BF%CB[/url]
cugb_cat
[quote]原帖由 [i]想飞的蜗牛[/i] 于 2008-2-18 20:43 发表 [url=http://bbs.chinaunix.net/redirect.php?goto=findpost&pid=7975026&ptid=1053225][img]http://bbs.chinaunix.net/images/common/back.gif[/img][/url]
:mrgreen: thx
搜贴的时候搜过思版的一篇文章，比较类似
http://bbs.chinaunix.net/viewthread.php?tid=941100&highlight=%CB%BC%D2%BB%BF%CB [/quote]
原来思版主已经总结过了，呵呵，用法说明详细多了。
bloblo
好贴 楼主辛苦咯 o(∩_∩)o 顶一下先*^__^* 学习中
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