kimi 输出双向链表
双向链表是：struct {xxx，list node}
每个 node 指向下一个结构体的 node 信息
#include <stdio.h>
#include <stdlib.h>
#include <string.h>// 定义双向链表节点结构体
struct list_head {struct list_head *next, *prev;
};// 初始化双向链表头节点
#define LIST_HEAD_INIT(name) { &(name), &(name) }// 定义双向链表头节点
#define LIST_HEAD(name) \struct list_head name = LIST_HEAD_INIT(name)// 初始化双向链表头节点的函数
static inline void INIT_LIST_HEAD(struct list_head *list)
{list->next = list;list->prev = list;
}// 内部函数，用于将新节点插入到指定位置
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;
}// 将新节点添加到链表头部
static inline void list_add(struct list_head *new, struct list_head *head)
{__list_add(new, head, head->next);
}// 将新节点添加到链表尾部
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{__list_add(new, head->prev, head);
}// 内部函数，用于删除节点的连接关系
static inline void __list_del(struct list_head *prev, struct list_head *next)
{next->prev = prev;prev->next = next;
}// 删除链表中的节点
static inline void list_del(struct list_head *entry)
{__list_del(entry->prev, entry->next);entry->next = NULL;entry->prev = NULL;
}// 判断链表是否为空
static inline int list_empty(const struct list_head *head)
{return head->next == head;
}// 获取链表中第一个节点的指针
#define list_first_entry(ptr, type, member) \list_entry((ptr)->next, type, member)// 获取链表中最后一个节点的指针
#define list_last_entry(ptr, type, member) \list_entry((ptr)->prev, type, member)// 获取当前节点的下一个节点的指针
#define list_next_entry(pos, member) \list_entry((pos)->member.next, typeof(*(pos)), member)// 获取当前节点的上一个节点的指针
#define list_prev_entry(pos, member) \list_entry((pos)->member.prev, typeof(*(pos)), member)// 根据成员变量的指针获取包含该成员变量的结构体的指针
#define list_entry(ptr, type, member) \((type *)((char *)(ptr) - (unsigned long)(&((type *)0)->member)))// 遍历双向链表的宏: 遍历的时候：根据node指针➕node在结构体中的偏移 来确定包含node的结构体指针
#define LIST_FOR_EACH_ENTRY(pos, head, member) \for (pos = list_first_entry(head, typeof(*pos), member); \&pos->member != (head); \pos = list_next_entry(pos, member))// 示例：定义一个学生结构体，包含链表节点
struct student {int id;char name[20];struct list_head list;
};int main() {// 初始化链表头节点LIST_HEAD(students_list);// 创建并初始化学生节点struct student stu1 = {1, "Alice", LIST_HEAD_INIT(stu1.list)};struct student stu2 = {2, "Bob", LIST_HEAD_INIT(stu2.list)};struct student stu3 = {3, "Charlie", LIST_HEAD_INIT(stu3.list)};// 将学生节点添加到链表中list_add(&stu1.list, &students_list);list_add(&stu2.list, &students_list);list_add_tail(&stu3.list, &students_list);// 遍历链表并打印学生信息struct student *pos;LIST_FOR_EACH_ENTRY(pos, &students_list, list) {printf("Student ID: %d, Name: %s\n", pos->id, pos->name);}// 删除链表中的节点list_del(&stu2.list);// 再次遍历链表并打印学生信息printf("After deleting stu2:\n");LIST_FOR_EACH_ENTRY(pos, &students_list, list) {printf("Student ID: %d, Name: %s\n", pos->id, pos->name);}return 0;
}
下面代码摘自 linux 内核代码 v6.7.1 LXR linux/include/linux/list.h
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H#include <linux/container_of.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/poison.h>
#include <linux/const.h>#include <asm/barrier.h>/** Circular 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_HEAD_INIT(name) { &(name), &(name) }#define LIST_HEAD(name) \struct list_head name = LIST_HEAD_INIT(name)/*** INIT_LIST_HEAD - Initialize a list_head structure* @list: list_head structure to be initialized.** Initializes the list_head to point to itself. If it is a list header,* the result is an empty list.*/
static inline void INIT_LIST_HEAD(struct list_head *list)
{WRITE_ONCE(list->next, list);WRITE_ONCE(list->prev, list);
}#ifdef CONFIG_LIST_HARDENED#ifdef CONFIG_DEBUG_LIST
# define __list_valid_slowpath
#else
# define __list_valid_slowpath __cold __preserve_most
#endif/** Performs the full set of list corruption checks before __list_add().* On list corruption reports a warning, and returns false.*/
extern bool __list_valid_slowpath __list_add_valid_or_report(struct list_head *new,struct list_head *prev,struct list_head *next);/** Performs list corruption checks before __list_add(). Returns false if a* corruption is detected, true otherwise.** With CONFIG_LIST_HARDENED only, performs minimal list integrity checking* inline to catch non-faulting corruptions, and only if a corruption is* detected calls the reporting function __list_add_valid_or_report().*/
static __always_inline bool __list_add_valid(struct list_head *new,struct list_head *prev,struct list_head *next)
{bool ret = true;if (!IS_ENABLED(CONFIG_DEBUG_LIST)) {/** With the hardening version, elide checking if next and prev* are NULL, since the immediate dereference of them below would* result in a fault if NULL.** With the reduced set of checks, we can afford to inline the* checks, which also gives the compiler a chance to elide some* of them completely if they can be proven at compile-time. If* one of the pre-conditions does not hold, the slow-path will* show a report which pre-condition failed.*/if (likely(next->prev == prev && prev->next == next && new != prev && new != next))return true;ret = false;}ret &= __list_add_valid_or_report(new, prev, next);return ret;
}/** Performs the full set of list corruption checks before __list_del_entry().* On list corruption reports a warning, and returns false.*/
extern bool __list_valid_slowpath __list_del_entry_valid_or_report(struct list_head *entry);/** Performs list corruption checks before __list_del_entry(). Returns false if a* corruption is detected, true otherwise.** With CONFIG_LIST_HARDENED only, performs minimal list integrity checking* inline to catch non-faulting corruptions, and only if a corruption is* detected calls the reporting function __list_del_entry_valid_or_report().*/
static __always_inline bool __list_del_entry_valid(struct list_head *entry)
{bool ret = true;if (!IS_ENABLED(CONFIG_DEBUG_LIST)) {struct list_head *prev = entry->prev;struct list_head *next = entry->next;/** With the hardening version, elide checking if next and prev* are NULL, LIST_POISON1 or LIST_POISON2, since the immediate* dereference of them below would result in a fault.*/if (likely(prev->next == entry && next->prev == entry))return true;ret = false;}ret &= __list_del_entry_valid_or_report(entry);return ret;
}
#else
static inline bool __list_add_valid(struct list_head *new,struct list_head *prev,struct list_head *next)
{return true;
}
static inline bool __list_del_entry_valid(struct list_head *entry)
{return true;
}
#endif/** 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)
{if (!__list_add_valid(new, prev, next))return;next->prev = new;new->next = next;new->prev = prev;WRITE_ONCE(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;WRITE_ONCE(prev->next, next);
}/** Delete a list entry and clear the 'prev' pointer.** This is a special-purpose list clearing method used in the networking code* for lists allocated as per-cpu, where we don't want to incur the extra* WRITE_ONCE() overhead of a regular list_del_init(). The code that uses this* needs to check the node 'prev' pointer instead of calling list_empty().*/
static inline void __list_del_clearprev(struct list_head *entry)
{__list_del(entry->prev, entry->next);entry->prev = NULL;
}static inline void __list_del_entry(struct list_head *entry)
{if (!__list_del_entry_valid(entry))return;__list_del(entry->prev, entry->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(entry);entry->next = LIST_POISON1;entry->prev = LIST_POISON2;
}/*** 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;
}/*** list_replace_init - replace old entry by new one and initialize the old 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_init(struct list_head *old,struct list_head *new)
{list_replace(old, new);INIT_LIST_HEAD(old);
}/*** list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position* @entry1: the location to place entry2* @entry2: the location to place entry1*/
static inline void list_swap(struct list_head *entry1,struct list_head *entry2)
{struct list_head *pos = entry2->prev;list_del(entry2);list_replace(entry1, entry2);if (pos == entry1)pos = entry2;list_add(entry1, pos);
}/*** 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_bulk_move_tail - move a subsection of a list to its tail* @head: the head that will follow our entry* @first: first entry to move* @last: last entry to move, can be the same as first** Move all entries between @first and including @last before @head.* All three entries must belong to the same linked list.*/
static inline void list_bulk_move_tail(struct list_head *head,struct list_head *first,struct list_head *last)
{first->prev->next = last->next;last->next->prev = first->prev;head->prev->next = first;first->prev = head->prev;last->next = head;head->prev = last;
}/*** list_is_first -- tests whether @list is the first entry in list @head* @list: the entry to test* @head: the head of the list*/
static inline int list_is_first(const struct list_head *list, const struct list_head *head)
{return list->prev == 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_is_head - tests whether @list is the list @head* @list: the entry to test* @head: the head of the list*/
static inline int list_is_head(const struct list_head *list, const struct list_head *head)
{return 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 READ_ONCE(head->next) == head;
}/*** list_del_init_careful - deletes entry from list and reinitialize it.* @entry: the element to delete from the list.** This is the same as list_del_init(), except designed to be used* together with list_empty_careful() in a way to guarantee ordering* of other memory operations.** Any memory operations done before a list_del_init_careful() are* guaranteed to be visible after a list_empty_careful() test.*/
static inline void list_del_init_careful(struct list_head *entry)
{__list_del_entry(entry);WRITE_ONCE(entry->prev, entry);smp_store_release(&entry->next, entry);
}/*** 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 = smp_load_acquire(&head->next);return list_is_head(next, head) && (next == READ_ONCE(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_rotate_to_front() - Rotate list to specific item.* @list: The desired new front of the list.* @head: The head of the list.** Rotates list so that @list becomes the new front of the list.*/
static inline void list_rotate_to_front(struct list_head *list,struct list_head *head)
{/** Deletes the list head from the list denoted by @head and* places it as the tail of @list, this effectively rotates the* list so that @list is at the front.*/list_move_tail(head, list);
}/*** 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) && !list_is_head(entry, head) && (entry != head->next))return;if (list_is_head(entry, head))INIT_LIST_HEAD(list);else__list_cut_position(list, head, entry);
}/*** list_cut_before - cut a list into two, before given entry* @list: a new list to add all removed entries* @head: a list with entries* @entry: an entry within head, could be the head itself** This helper moves the initial part of @head, up to but* excluding @entry, from @head to @list. You should pass* in @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.* If @entry == @head, all entries on @head are moved to* @list.*/
static inline void list_cut_before(struct list_head *list,struct list_head *head,struct list_head *entry)
{if (head->next == entry) {INIT_LIST_HEAD(list);return;}list->next = head->next;list->next->prev = list;list->prev = entry->prev;list->prev->next = list;head->next = entry;entry->prev = 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;
}/*** 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_head 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_head 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_last_entry - get the last 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_head within the struct.** Note, that list is expected to be not empty.*/
#define list_last_entry(ptr, type, member) \list_entry((ptr)->prev, type, member)/*** list_first_entry_or_null - 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_head within the struct.** Note that if the list is empty, it returns NULL.*/
#define list_first_entry_or_null(ptr, type, member) ({ \struct list_head *head__ = (ptr); \struct list_head *pos__ = READ_ONCE(head__->next); \pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
})/*** list_next_entry - get the next element in list* @pos: the type * to cursor* @member: the name of the list_head within the struct.*/
#define list_next_entry(pos, member) \list_entry((pos)->member.next, typeof(*(pos)), member)/*** list_next_entry_circular - get the next element in list* @pos: the type * to cursor.* @head: the list head to take the element from.* @member: the name of the list_head within the struct.** Wraparound if pos is the last element (return the first element).* Note, that list is expected to be not empty.*/
#define list_next_entry_circular(pos, head, member) \(list_is_last(&(pos)->member, head) ? \list_first_entry(head, typeof(*(pos)), member) : list_next_entry(pos, member))/*** list_prev_entry - get the prev element in list* @pos: the type * to cursor* @member: the name of the list_head within the struct.*/
#define list_prev_entry(pos, member) \list_entry((pos)->member.prev, typeof(*(pos)), member)/*** list_prev_entry_circular - get the prev element in list* @pos: the type * to cursor.* @head: the list head to take the element from.* @member: the name of the list_head within the struct.** Wraparound if pos is the first element (return the last element).* Note, that list is expected to be not empty.*/
#define list_prev_entry_circular(pos, head, member) \(list_is_first(&(pos)->member, head) ? \list_last_entry(head, typeof(*(pos)), member) : list_prev_entry(pos, 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; !list_is_head(pos, (head)); pos = pos->next)/*** list_for_each_reverse - iterate backwards over a list* @pos: the &struct list_head to use as a loop cursor.* @head: the head for your list.*/
#define list_for_each_reverse(pos, head) \for (pos = (head)->prev; pos != (head); pos = pos->prev)/*** list_for_each_rcu - Iterate over a list in an RCU-safe fashion* @pos: the &struct list_head to use as a loop cursor.* @head: the head for your list.*/
#define list_for_each_rcu(pos, head) \for (pos = rcu_dereference((head)->next); \!list_is_head(pos, (head)); \pos = rcu_dereference(pos->next))/*** list_for_each_continue - continue iteration over a list* @pos: the &struct list_head to use as a loop cursor.* @head: the head for your list.** Continue to iterate over a list, continuing after the current position.*/
#define list_for_each_continue(pos, head) \for (pos = pos->next; !list_is_head(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; !list_is_head(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; \!list_is_head(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; \!list_is_head(pos, (head)); \pos = n, n = pos->prev)/*** list_count_nodes - count nodes in the list* @head: the head for your list.*/
static inline size_t list_count_nodes(struct list_head *head)
{struct list_head *pos;size_t count = 0;list_for_each(pos, head)count++;return count;
}/*** list_entry_is_head - test if the entry points to the head of the list* @pos: the type * to cursor* @head: the head for your list.* @member: the name of the list_head within the struct.*/
#define list_entry_is_head(pos, head, member) \(&pos->member == (head))/*** 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_head within the struct.*/
#define list_for_each_entry(pos, head, member) \for (pos = list_first_entry(head, typeof(*pos), member); \!list_entry_is_head(pos, head, member); \pos = list_next_entry(pos, member))
