#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "list.h"
/**
* @brief 这个是内核链表的一个demo
* 1. 第一自己需要的数据类型 ，其中必须包含一个 struct list_head 的变量
2. 定义头节点，并初始化
3. 增加结点，malloc自己的结构体，填入自己需要的数据 调用list_add
，把当前结点加入链表
4. 遍历所有元素list_for_each_entry_safe，
*/
typedef struct
{
int id;
char name[50];
struct list_head node;
} PER;
int add_per(struct list_head *head, int id, char *name)
{
PER *per = malloc(sizeof(PER));
if (NULL == per)
{
perror("add_per malloc error\n");
return 1;
}
per->id = id;
strcpy(per->name, name);
//头插
// list_add(&per->node, head);
list_add_
tail(&per->node, head);
return 0;
}
int
show(struct list_head *head)
{
// 遍历所有数据，
// pos 当前要访问的PER结构体指针 ，n是pos的下一个指针 ，
// head 链表的头结点
// member 在自定义的结构体中 结点的变量名
// list_for_each_entry_safe(pos, n, head, member) for
PER *tmp;
PER *next;
list_for_each_entry_safe(tmp, next, head, node)
{
printf("%d %s\n", tmp->id, tmp->name);
}
return 0;
}
/**
* @brief
*
* @param head
* @param id 需要删除数据的编号
* @return int
*/
PER* find_per(struct list_head *head, char *name)
{
PER *tmp;
list_for_each_entry(tmp, head, node)
{
if (strcmp(tmp->name, name) == 0)
{
printf("找到节点:id=%d, name=%s\n", tmp->id, tmp->name);
return tmp;
}
}
printf("未找到姓名为「%s」的节点\n", name);
return NULL;
}
int modify_per(struct list_head *head, char *old_name, int new_id, char *new_name)
{
PER *target = find_per(head, old_name);
if (target == NULL)
{
return 1;
}
target->id = new_id;
if (strlen(new_name) >= sizeof(target->name))
{
printf("无效名字");
return 2;
}
strcpy(target->name, new_name);
printf("修改成功：原姓名「%s」→ 新id=%d, 新姓名「%s」\n", old_name, new_id, new_name);
return 0;
}
int del_per(struct list_head *head, int id)
{
PER *tmp;
PER *next;
list_for_each_entry_safe(tmp, next, head, node)
{
if (tmp->id == id)
{
list_del(&tmp->node);
free(tmp);
}
}
return 0;
}
int main(int argc, char **argv)
{
//头结点，不包含有效数据，head->next 是链表中第一个有效数据
struct list_head head;
//双向循环链表， 当前结点的prev，next 都指向自己
INIT_LIST_HEAD(&head);
add_per(&head, 1, "zhagnsan");
add_per(&head, 2, "lisi");
add_per(&head, 3, "wangmazi");
add_per(&head, 4, "guanerge");
add_per(&head, 5, "liubei ");
show(&head);
del_per(&head, 1);
printf("------------del--------------\n");
show(&head);
find_per(&head, "lisi");
// system("pause");
return 0;
}
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H
#include <linux/stddef.h>
#include <stdio.h>
//#include <linux/poison.h>
//#include <linux/prefetch.h>
//#include <asm/system.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.
*/
// #define LIST_POISON1 ((void *) 0x00100100)
// #define LIST_POISON2 ((void *) 0x00200200)
#define LIST_POISON1 ((void *) 0)
#define LIST_POISON2 ((void *) 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) );})
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)
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 (struct list_head *entry)
{
__list_del (entry->prev, entry->next);
entry->next = LIST_POISON1;
entry->prev = LIST_POISON2;
}
#else
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->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_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_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; prefetch (pos->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 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 cursor.
* @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 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; \
prefetch (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); \
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 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); \
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 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); \
prefetch (pos->member.next), &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); \
prefetch (pos->member.prev), &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 (; 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 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
* @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
* @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
* @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))
/*
* 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).
*/
struct hlist_head {
struct hlist_node *
first;
};
struct hlist_node {
struct hlist_node *next, **pprev;
};
#define HLIST_HEAD_INIT \
{ \
.
first = NULL \
}
#define HLIST_HEAD(name) struct hlist_head name = { .
first = NULL }
#define INIT_HLIST_HEAD(ptr) ((ptr)->
first = NULL)
static inline void INIT_HLIST_NODE (struct hlist_node *h)
{
h->next = NULL;
h->pprev = NULL;
}
static inline int hlist_unhashed (const struct hlist_node *h)
{
return !h->pprev;
}
static inline int hlist_empty (const struct hlist_head *h)
{
return !h->
first;
}
static inline void __hlist_del (struct hlist_node *n)
{
struct hlist_node *next = n->next;
struct hlist_node **pprev = n->pprev;
*pprev = next;
if (next)
next->pprev = pprev;
}
static inline void hlist_del (struct hlist_node *n)
{
__hlist_del (n);
n->next = LIST_POISON1;
n->pprev = LIST_POISON2;
}
static inline void hlist_del_init (struct hlist_node *n)
{
if (!hlist_unhashed (n)) {
__hlist_del (n);
INIT_HLIST_NODE (n);
}
}
static inline void hlist_add_head (struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *
first = h->
first;
n->next =
first;
if (
first)
first->pprev = &n->next;
h->
first = n;
n->pprev = &h->
first;
}
/* next must be != NULL */
static inline void hlist_add_before (struct hlist_node *n,
struct hlist_node *next)
{
n->pprev = next->pprev;
n->next = next;
next->pprev = &n->next;
*(n->pprev) = n;
}
static inline void hlist_add_after (struct hlist_node *n,
struct hlist_node *next)
{
next->next = n->next;
n->next = next;
next->pprev = &n->next;
if (next->next)
next->next->pprev = &next->next;
}
/*
* Move a list from one list head to another. Fixup the pprev
* reference of the
first entry if it exists.
*/
static inline void hlist_move_list (struct hlist_head *old,
struct hlist_head *new)
{
new->
first = old->
first;
if (new->
first)
new->
first->pprev = &new->
first;
old->
first = NULL;
}
#define hlist_entry(ptr, type, member) container_of (ptr, type, member)
#define hlist_for_each(pos, head) \
for (pos = (head)->
first; pos && ({ \
prefetch (pos->next); \
1; \
}); \
pos = pos->next)
#define hlist_for_each_safe(pos, n, head) \
for (pos = (head)->
first; pos && ({ \
n = pos->next; \
1; \
}); \
pos = n)
/**
* hlist_for_each_entry - iterate over list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry(tpos, pos, head, member) \
for (pos = (head)->
first; \
pos && ({ \
prefetch (pos->next); \
1; \
}) \
&& ({ \
tpos = hlist_entry (pos, typeof(*tpos), member); \
1; \
}); \
pos = pos->next)
/**
* hlist_for_each_entry_continue - iterate over a hlist continuing after
* current point
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_continue(tpos, pos, member) \
for (pos = (pos)->next; \
pos && ({ \
prefetch (pos->next); \
1; \
}) \
&& ({ \
tpos = hlist_entry (pos, typeof(*tpos), member); \
1; \
}); \
pos = pos->next)
/**
* hlist_for_each_entry_from - iterate over a hlist continuing from current
* point
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_from(tpos, pos, member) \
for (; pos && ({ \
prefetch (pos->next); \
1; \
}) \
&& ({ \
tpos = hlist_entry (pos, typeof(*tpos), member); \
1; \
}); \
pos = pos->next)
/**
* hlist_for_each_entry_safe - iterate over list of given type safe against
* removal of list entry
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @n: another &struct hlist_node to use as temporary storage
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
for (pos = (head)->
first; \
pos && ({ \
n = pos->next; \
1; \
}) \
&& ({ \
tpos = hlist_entry (pos, typeof(*tpos), member); \
1; \
}); \
pos = n)
#endif
错误信息为In file included from main.c:4:0:
main.c: In function ‘find_per’:
list.h:417:8: warning: implicit declaration of function ‘prefetch’; did you mean ‘rpmatch’? [-Wimplicit-function-declaration]
prefetch (pos->member.next), &pos->member != (head); \
^
main.c:63:5: note: in expansion of macro ‘list_for_each_entry’
list_for_each_entry(tmp, head, node)
^~~~~~~~~~~~~~~~~~~
/tmp/cce8BVSj.o: In function `find_per':
main.c:(.text+0x297): undefined reference to `prefetch'
collect2: error: ld returned 1 exit status,该如何修改
本文深入解析RDD的各种操作，如first(), head(), show(), take(), collect()和tail()等方法的底层实现与应用场景。详细阐述了这些方法如何触发Spark作业执行，以及在大数据处理中可能遇到的内存溢出问题。
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