230 lines
6.7 KiB
C
230 lines
6.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* stripped down version of my adaptation of Linux kernel lists management :
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* https://github.com/braoult/Tools/blob/master/C/list.h
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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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#include <stdbool.h>
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/************ originally in <include/linux/types.h> */
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struct list_head {
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struct list_head *next, *prev;
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};
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/************ originally in <include/linux/poison.h> */
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#define LIST_POISON1 ((void *) 0x100)
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#define LIST_POISON2 ((void *) 0x122)
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/************ originally in <include/linux/kernel.h> */
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#define container_of(ptr, type, member) \
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((type *)((char *)(ptr) - offsetof(type, member)))
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/*
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* Circular doubly linked list implementation.
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*
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* Some of the internal functions ("__xxx") are useful when
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* manipulating whole lists rather than single entries, as
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* sometimes we already know the next/prev entries and we can
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* generate better code by using them directly rather than
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* using the generic single-entry routines.
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*/
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/**
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* INIT_LIST_HEAD - Initialize a list_head structure
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* @list: list_head structure to be initialized.
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*
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* Initializes the list_head to point to itself. If it is a list header,
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* the result is an empty list.
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*/
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static inline void INIT_LIST_HEAD(struct list_head *list)
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{
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list->next = list;
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list->prev = list;
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}
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/*
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* Insert a new entry between two known consecutive entries.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_add(struct list_head *new,
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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 = new;
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new->next = next;
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new->prev = prev;
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prev->next = new;
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}
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/**
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* list_add - add a new entry
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* @new: new entry to be added
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* @head: list head to add it after
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*
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* Insert a new entry after the specified head.
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* This is good for implementing stacks.
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*/
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static inline void list_add(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head, head->next);
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}
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/**
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* list_add_tail - add a new entry
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* @new: new entry to be added
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* @head: list head to add it before
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*
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* Insert a new entry before the specified head.
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* This is useful for implementing queues.
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*/
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static inline void list_add_tail(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head->prev, head);
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}
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/*
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* Delete a list entry by making the prev/next entries
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* point to each other.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_del(struct list_head * prev, 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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static inline void __list_del_entry(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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}
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/**
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* list_del - deletes entry from list.
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* @entry: the element to delete from the list.
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* Note: list_empty() on entry does not return true after this, the entry is
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* in an undefined state.
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*/
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static inline void list_del(struct list_head *entry)
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{
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__list_del_entry(entry);
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entry->next = LIST_POISON1;
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entry->prev = LIST_POISON2;
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}
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/**
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* list_empty - tests whether a list is empty
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* @head: the list to test.
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*/
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static inline int list_empty(const struct list_head *head)
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{
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return head->next == head;
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}
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/**
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* list_entry - get the struct for this entry
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* @ptr: the &struct list_head pointer.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*/
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#define list_entry(ptr, type, member) \
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container_of(ptr, type, member)
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/**
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* list_first_entry - get the first element from a list
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* @ptr: the list head to take the element from.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*
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* Note, that list is expected to be not empty.
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*/
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#define list_first_entry(ptr, type, member) \
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list_entry((ptr)->next, type, member)
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/**
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* list_last_entry - get the last element from a list
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* @ptr: the list head to take the element from.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_head within the struct.
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*
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* Note, that list is expected to be not empty.
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*/
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#define list_last_entry(ptr, type, member) \
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list_entry((ptr)->prev, type, member)
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/**
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* list_next_entry - get the next element in list
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* @pos: the type * to cursor
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* @member: the name of the list_head within the struct.
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*/
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#define list_next_entry(pos, member) \
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list_entry((pos)->member.next, __typeof__(*(pos)), member)
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/**
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* list_prev_entry - get the prev element in list
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* @pos: the type * to cursor
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* @member: the name of the list_head within the struct.
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*/
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#define list_prev_entry(pos, member) \
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list_entry((pos)->member.prev, __typeof__(*(pos)), member)
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/**
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* list_for_each - iterate over a list
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* @pos: the &struct list_head to use as a loop cursor.
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* @head: the head for your list.
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*/
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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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/**
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* list_for_each_safe - iterate over a list safe against removal of list entry
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* @pos: the &struct list_head to use as a loop cursor.
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* @n: another &struct list_head to use as temporary storage
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* @head: the head for your list.
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*/
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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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/**
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* list_entry_is_head - test if the entry points to the head of the list
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* @pos: the type * to cursor
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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#define list_entry_is_head(pos, head, member) \
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(&pos->member == (head))
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/**
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* list_for_each_entry - iterate over list of given type
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* @pos: the type * to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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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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!list_entry_is_head(pos, head, member); \
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pos = list_next_entry(pos, member))
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/**
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* list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
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* @pos: the type * to use as a loop cursor.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_head within the struct.
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*/
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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_next_entry(pos, member); \
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!list_entry_is_head(pos, head, member); \
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pos = n, n = list_next_entry(n, member))
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#endif /* __LIST_H */
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