[systemd.git] / src / shared / list.h

/*-*- 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)

/* 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)

/* 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))
Commit	Line	Data
663996b3 MS	1	/-- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil --/
	2
	3	#pragma once
	4
	5	/***
	6	This file is part of systemd.
	7
	8	Copyright 2010 Lennart Poettering
	9
	10	systemd is free software; you can redistribute it and/or modify it
	11	under the terms of the GNU Lesser General Public License as published by
	12	the Free Software Foundation; either version 2.1 of the License, or
	13	(at your option) any later version.
	14
	15	systemd is distributed in the hope that it will be useful, but
	16	WITHOUT ANY WARRANTY; without even the implied warranty of
	17	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	18	Lesser General Public License for more details.
	19
	20	You should have received a copy of the GNU Lesser General Public License
	21	along with systemd; If not, see <http://www.gnu.org/licenses/>.
	22	***/
	23
	24	/* The head of the linked list. Use this in the structure that shall
	25	* contain the head of the linked list */
	26	#define LIST_HEAD(t,name) \
	27	t *name
	28
	29	/* The pointers in the linked list's items. Use this in the item structure */
	30	#define LIST_FIELDS(t,name) \
	31	t name##_next, name##_prev
	32
	33	/* Initialize the list's head */
60f067b4	34	#define LIST_HEAD_INIT(head) \
663996b3 MS	35	do { \
	36	(head) = NULL; } \
	37	while(false)
	38
	39	/* Initialize a list item */
60f067b4	40	#define LIST_INIT(name,item) \
663996b3	41	do { \
60f067b4	42	typeof((item)) _item = (item); \
663996b3 MS	43	assert(_item); \
	44	_item->name##_prev = _item->name##_next = NULL; \
	45	} while(false)
	46
	47	/* Prepend an item to the list */
60f067b4	48	#define LIST_PREPEND(name,head,item) \
663996b3	49	do { \
60f067b4	50	typeof((head)) _head = &(head), _item = (item); \
663996b3 MS	51	assert(_item); \
	52	if ((_item->name##_next = *_head)) \
	53	_item->name##_next->name##_prev = _item; \
	54	_item->name##_prev = NULL; \
	55	*_head = _item; \
	56	} while(false)
	57
	58	/* Remove an item from the list */
60f067b4	59	#define LIST_REMOVE(name,head,item) \
663996b3	60	do { \
60f067b4	61	typeof((head)) _head = &(head), _item = (item); \
663996b3 MS	62	assert(_item); \
	63	if (_item->name##_next) \
	64	_item->name##_next->name##_prev = _item->name##_prev; \
	65	if (_item->name##_prev) \
	66	_item->name##_prev->name##_next = _item->name##_next; \
	67	else { \
	68	assert(*_head == _item); \
	69	*_head = _item->name##_next; \
	70	} \
	71	_item->name##_next = _item->name##_prev = NULL; \
	72	} while(false)
	73
	74	/* Find the head of the list */
60f067b4	75	#define LIST_FIND_HEAD(name,item,head) \
663996b3	76	do { \
60f067b4 JS	77	typeof((item)) _item = (item); \
	78	if (!_item) \
	79	(head) = NULL; \
	80	else { \
	81	while (_item->name##_prev) \
	82	_item = _item->name##_prev; \
	83	(head) = _item; \
	84	} \
663996b3 MS	85	} while (false)
663996b3 MS	86
14228c0d	87	/* Find the tail of the list */
60f067b4	88	#define LIST_FIND_TAIL(name,item,tail) \
663996b3	89	do { \
60f067b4 JS	90	typeof((item)) _item = (item); \
	91	if (!_item) \
	92	(tail) = NULL; \
	93	else { \
	94	while (_item->name##_next) \
	95	_item = _item->name##_next; \
	96	(tail) = _item; \
	97	} \
663996b3 MS	98	} while (false)
	99
	100	/* Insert an item after another one (a = where, b = what) */
60f067b4	101	#define LIST_INSERT_AFTER(name,head,a,b) \
663996b3	102	do { \
60f067b4	103	typeof((head)) _head = &(head), _a = (a), *_b = (b); \
663996b3 MS	104	assert(_b); \
	105	if (!_a) { \
	106	if ((_b->name##_next = *_head)) \
	107	_b->name##_next->name##_prev = _b; \
	108	_b->name##_prev = NULL; \
	109	*_head = _b; \
	110	} else { \
	111	if ((_b->name##_next = _a->name##_next)) \
	112	_b->name##_next->name##_prev = _b; \
	113	_b->name##_prev = _a; \
	114	_a->name##_next = _b; \
	115	} \
	116	} while(false)
	117
	118	#define LIST_JUST_US(name,item) \
	119	(!(item)->name##_prev && !(item)->name##_next) \
	120
	121	#define LIST_FOREACH(name,i,head) \
	122	for ((i) = (head); (i); (i) = (i)->name##_next)
	123
	124	#define LIST_FOREACH_SAFE(name,i,n,head) \
	125	for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
	126
	127	#define LIST_FOREACH_BEFORE(name,i,p) \
	128	for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
	129
	130	#define LIST_FOREACH_AFTER(name,i,p) \
	131	for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
14228c0d MB	132
	133	/* Loop starting from p->next until p->prev.
	134	p can be adjusted meanwhile. */
	135	#define LIST_LOOP_BUT_ONE(name,i,head,p) \
	136	for ((i) = (p)->name##_next ? (p)->name##_next : (head); \
	137	(i) != (p); \
	138	(i) = (i)->name##_next ? (i)->name##_next : (head))