204 lines
5.2 KiB
C
204 lines
5.2 KiB
C
/**
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* @file list.h
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* @brief Linux 内核风格侵入式双向循环链表（纯头文件，C/C++ 兼容）
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* @details 将 struct list_head 嵌入宿主结构体，通过 list_entry 取回宿主指针。
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* 所有操作 O(1)，遍历 O(n)。
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* C++ 兼容：变量名不使用 new/class/typeof 等关键字。
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*/
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#ifndef _LIST_H_
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#define _LIST_H_
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/* ---- 链表节点 ---- */
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struct list_head
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{
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struct list_head *next;
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struct list_head *prev;
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};
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/* ---- 初始化 ---- */
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#define LIST_HEAD_INIT(n) { &(n), &(n) }
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#define LIST_HEAD(n) struct list_head n = LIST_HEAD_INIT(n)
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/**
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* @brief 运行时初始化链表头
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*/
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static inline void INIT_LIST_HEAD(struct list_head *h)
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{
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h->next = h;
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h->prev = h;
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}
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/* ---- 内部辅助：在 prev 和 next 之间插入 node ---- */
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static inline void __list_add(struct list_head *node,
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struct list_head *prev,
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struct list_head *next)
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{
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next->prev = node;
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node->next = next;
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node->prev = prev;
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prev->next = node;
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}
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/* ---- 内部辅助：移除 prev 和 next 之间的节点 ---- */
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static inline void __list_del(struct list_head *prev,
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struct list_head *next)
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{
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next->prev = prev;
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prev->next = next;
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}
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/* ---- 添加操作 ---- */
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/** 头插法：插入到 head 之后（作为第一个元素） */
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static inline void list_add(struct list_head *node, struct list_head *head)
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{
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__list_add(node, head, head->next);
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}
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/** 尾插法：插入到 head 之前（作为最后一个元素） */
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static inline void list_add_tail(struct list_head *node, struct list_head *head)
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{
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__list_add(node, head->prev, head);
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}
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/* ---- 删除操作 ---- */
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/** 从链表移除节点（不释放内存） */
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static inline void list_del(struct list_head *e)
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{
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__list_del(e->prev, e->next);
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}
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/** 移除并重新初始化节点（安全删除，防止悬空指针） */
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static inline void list_del_init(struct list_head *e)
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{
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__list_del(e->prev, e->next);
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INIT_LIST_HEAD(e);
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}
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/* ---- 移动操作 ---- */
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/** 将节点移动到新链表头部 */
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static inline void list_move(struct list_head *l, struct list_head *h)
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{
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__list_del(l->prev, l->next);
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list_add(l, h);
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}
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/** 将节点移动到新链表尾部 */
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static inline void list_move_tail(struct list_head *l, struct list_head *h)
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{
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__list_del(l->prev, l->next);
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list_add_tail(l, h);
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}
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/* ---- 替换操作 ---- */
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/** 用 node 替换 old */
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static inline void list_replace(struct list_head *old, struct list_head *node)
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{
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node->next = old->next;
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node->next->prev = node;
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node->prev = old->prev;
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node->prev->next = node;
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}
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/** 替换后初始化被替换节点 */
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static inline void list_replace_init(struct list_head *old,
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struct list_head *node)
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{
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list_replace(old, node);
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INIT_LIST_HEAD(old);
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}
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/* ---- 判断操作 ---- */
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/** 判断链表是否为空 */
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static inline int list_empty(const struct list_head *h)
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{
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return h->next == h;
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}
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/** 判断节点是否已链入链表 */
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static inline int list_is_linked(const struct list_head *e)
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{
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return e->next != e;
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}
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/* ---- 节点 ↔ 宿主指针转换 ---- */
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/** 从链表节点指针取回宿主结构体指针 */
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#define list_entry(ptr, type, member) \
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((type *)((char *)(ptr) - offsetof(type, member)))
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/** 获取第一个宿主元素 */
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#define list_first_entry(h, type, member) \
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list_entry((h)->next, type, member)
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/** 获取最后一个宿主元素 */
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#define list_last_entry(h, type, member) \
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list_entry((h)->prev, type, member)
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/** 安全获取第一个元素（链表空返回 NULL） */
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#define list_first_entry_or_null(h, type, member) \
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(list_empty(h) ? NULL : list_first_entry(h, type, member))
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/* ---- 遍历操作 ---- */
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/** 遍历链表节点（仅获取 struct list_head 指针） */
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#define list_for_each(pos, head) \
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for (pos = (head)->next; pos != (head); pos = pos->next)
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/** 安全遍历节点（可在遍历中删除 pos） */
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#define list_for_each_safe(pos, n, head) \
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for (pos = (head)->next, n = pos->next; pos != (head); \
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pos = n, n = pos->next)
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/** 遍历宿主元素 */
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#define list_for_each_entry(pos, head, member) \
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for (pos = list_first_entry(head, __typeof__(*pos), member); \
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&pos->member != (head); \
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pos = list_entry(pos->member.next, __typeof__(*pos), member))
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/** 安全遍历宿主元素（可在遍历中删除 pos） */
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#define list_for_each_entry_safe(pos, n, head, member) \
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for (pos = list_first_entry(head, __typeof__(*pos), member), \
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n = list_entry(pos->member.next, __typeof__(*pos), member); \
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&pos->member != (head); \
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pos = n, \
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n = list_entry(n->member.next, __typeof__(*n), member))
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/* ---- 拼接操作 ---- */
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/** 将 src 链表拼接到 dst 头部，src 被清空 */
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static inline void list_splice_init(struct list_head *src,
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struct list_head *dst)
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{
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if (!list_empty(src))
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{
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struct list_head *f = src->next;
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struct list_head *l = src->prev;
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struct list_head *a = dst->next;
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f->prev = dst;
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dst->next = f;
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l->next = a;
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a->prev = l;
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INIT_LIST_HEAD(src);
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}
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* _LIST_H_ */
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