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d0e13f8774
We copied include/list.h from Linux kernel, and it's of course in GPLv2. This has raised concerns to many people, as it's not clear whether such a code is considered to be completely trivial, thus it might be seen as a derivative work, which takes effect in GPL, as suggested by Clemens. For clearing the situation, this patch replaces the existing list.h implementation from a new version. The API is kept to be compatible, but the codes were written from full scratch under LGPL, to be aligned with other alsa-lib codes. Reported-by: Clemens Lang <clemens.lang@bmw-carit.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
102 lines
2.7 KiB
C
102 lines
2.7 KiB
C
/* Doubly linked list macros compatible with Linux kernel's version
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* Copyright (c) 2015 by Takashi Iwai <tiwai@suse.de>
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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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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struct list_head {
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struct list_head *next;
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struct list_head *prev;
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};
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/* one-shot definition of a list head */
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#define LIST_HEAD(x) \
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struct list_head x = { &x, &x }
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/* initialize a list head explicitly */
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static inline void INIT_LIST_HEAD(struct list_head *p)
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{
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p->next = p->prev = p;
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}
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#define list_entry_offset(p, type, offset) \
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((type *)((char *)(p) - (offset)))
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/* list_entry - retrieve the original struct from list_head
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* @p: list_head pointer
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* @type: struct type
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* @member: struct field member containing the list_head
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*/
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#define list_entry(p, type, member) \
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list_entry_offset(p, type, offsetof(type, member))
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/* list_for_each - iterate over the linked list
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* @p: iterator, a list_head pointer variable
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* @list: list_head pointer containing the list
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*/
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#define list_for_each(p, list) \
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for (p = (list)->next; p != (list); p = p->next)
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/* list_for_each_safe - iterate over the linked list, safe to delete
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* @p: iterator, a list_head pointer variable
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* @s: a temporary variable to keep the next, a list_head pointer, too
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* @list: list_head pointer containing the list
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*/
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#define list_for_each_safe(p, s, list) \
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for (p = (list)->next; s = p->next, p != (list); p = s)
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/* list_add - prepend a list entry at the head
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* @p: the new list entry to add
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* @list: the list head
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*/
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static inline void list_add(struct list_head *p, struct list_head *list)
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{
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struct list_head *first = list->next;
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p->next = first;
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first->prev = p;
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list->next = p;
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p->prev = list;
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}
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/* list_add_tail - append a list entry at the tail
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* @p: the new list entry to add
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* @list: the list head
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*/
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static inline void list_add_tail(struct list_head *p, struct list_head *list)
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{
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struct list_head *last = list->prev;
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last->next = p;
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p->prev = last;
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p->next = list;
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list->prev = p;
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}
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/* list_del - delete the given list entry */
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static inline void list_del(struct list_head *p)
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{
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p->prev->next = p->next;
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p->next->prev = p->prev;
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}
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/* list_empty - returns 1 if the given list is empty */
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static inline int list_empty(const struct list_head *p)
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{
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return p->next == p;
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}
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#endif /* _LIST_H */
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