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systemd/src/shared/list.h
2015-01-28 14:04:23 +01:00

159 lines
8.5 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
/* The head of the linked list. Use this in the structure that shall
* contain the head of the linked list */
#define LIST_HEAD(t,name) \
t *name
/* The pointers in the linked list's items. Use this in the item structure */
#define LIST_FIELDS(t,name) \
t *name##_next, *name##_prev
/* Initialize the list's head */
#define LIST_HEAD_INIT(head) \
do { \
(head) = NULL; } \
while(false)
/* Initialize a list item */
#define LIST_INIT(name,item) \
do { \
typeof(*(item)) *_item = (item); \
assert(_item); \
_item->name##_prev = _item->name##_next = NULL; \
} while(false)
/* Prepend an item to the list */
#define LIST_PREPEND(name,head,item) \
do { \
typeof(*(head)) **_head = &(head), *_item = (item); \
assert(_item); \
if ((_item->name##_next = *_head)) \
_item->name##_next->name##_prev = _item; \
_item->name##_prev = NULL; \
*_head = _item; \
} while(false)
/* Append an item to the list */
#define LIST_APPEND(name,head,item) \
do { \
typeof(*(head)) *_tail; \
LIST_FIND_TAIL(name,head,_tail); \
LIST_INSERT_AFTER(name,head,_tail,item); \
} while(false)
/* Remove an item from the list */
#define LIST_REMOVE(name,head,item) \
do { \
typeof(*(head)) **_head = &(head), *_item = (item); \
assert(_item); \
if (_item->name##_next) \
_item->name##_next->name##_prev = _item->name##_prev; \
if (_item->name##_prev) \
_item->name##_prev->name##_next = _item->name##_next; \
else { \
assert(*_head == _item); \
*_head = _item->name##_next; \
} \
_item->name##_next = _item->name##_prev = NULL; \
} while(false)
/* Find the head of the list */
#define LIST_FIND_HEAD(name,item,head) \
do { \
typeof(*(item)) *_item = (item); \
if (!_item) \
(head) = NULL; \
else { \
while (_item->name##_prev) \
_item = _item->name##_prev; \
(head) = _item; \
} \
} while (false)
/* Find the tail of the list */
#define LIST_FIND_TAIL(name,item,tail) \
do { \
typeof(*(item)) *_item = (item); \
if (!_item) \
(tail) = NULL; \
else { \
while (_item->name##_next) \
_item = _item->name##_next; \
(tail) = _item; \
} \
} while (false)
/* Insert an item after another one (a = where, b = what) */
#define LIST_INSERT_AFTER(name,head,a,b) \
do { \
typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
assert(_b); \
if (!_a) { \
if ((_b->name##_next = *_head)) \
_b->name##_next->name##_prev = _b; \
_b->name##_prev = NULL; \
*_head = _b; \
} else { \
if ((_b->name##_next = _a->name##_next)) \
_b->name##_next->name##_prev = _b; \
_b->name##_prev = _a; \
_a->name##_next = _b; \
} \
} while(false)
#define LIST_JUST_US(name,item) \
(!(item)->name##_prev && !(item)->name##_next) \
#define LIST_FOREACH(name,i,head) \
for ((i) = (head); (i); (i) = (i)->name##_next)
#define LIST_FOREACH_SAFE(name,i,n,head) \
for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
#define LIST_FOREACH_BEFORE(name,i,p) \
for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
#define LIST_FOREACH_AFTER(name,i,p) \
for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
/* Iterate through all the members of the list p is included in, but skip over p */
#define LIST_FOREACH_OTHERS(name,i,p) \
for (({ \
(i) = (p); \
while ((i) && (i)->name##_prev) \
(i) = (i)->name##_prev; \
if ((i) == (p)) \
(i) = (p)->name##_next; \
}); \
(i); \
(i) = (i)->name##_next == (p) ? (p)->name##_next : (i)->name##_next)
/* Loop starting from p->next until p->prev.
p can be adjusted meanwhile. */
#define LIST_LOOP_BUT_ONE(name,i,head,p) \
for ((i) = (p)->name##_next ? (p)->name##_next : (head); \
(i) != (p); \
(i) = (i)->name##_next ? (i)->name##_next : (head))