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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/basic/list.h
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/list.h')
-rw-r--r--src/basic/list.h209
1 files changed, 209 insertions, 0 deletions
diff --git a/src/basic/list.h b/src/basic/list.h
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+++ b/src/basic/list.h
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+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
+
+/* 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) \
+ ({ \
+ 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; \
+ _item; \
+ })
+
+/* Append an item to the list */
+#define LIST_APPEND(name,head,item) \
+ ({ \
+ typeof(*(head)) **_hhead = &(head), *_tail; \
+ _tail = LIST_FIND_TAIL(name, *_hhead); \
+ LIST_INSERT_AFTER(name, *_hhead, _tail, item); \
+ })
+
+/* Remove an item from the list */
+#define LIST_REMOVE(name,head,item) \
+ ({ \
+ 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; \
+ _item; \
+ })
+
+/* Find the head of the list */
+#define LIST_FIND_HEAD(name,item) \
+ ({ \
+ typeof(*(item)) *_item = (item); \
+ while (_item && _item->name##_prev) \
+ _item = _item->name##_prev; \
+ _item; \
+ })
+
+/* Find the tail of the list */
+#define LIST_FIND_TAIL(name,item) \
+ ({ \
+ typeof(*(item)) *_item = (item); \
+ while (_item && _item->name##_next) \
+ _item = _item->name##_next; \
+ _item; \
+ })
+
+/* Insert an item after another one (a = where, b = what) */
+#define LIST_INSERT_AFTER(name,head,a,b) \
+ ({ \
+ 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; \
+ } \
+ _b; \
+ })
+
+/* Insert an item before another one (a = where, b = what) */
+#define LIST_INSERT_BEFORE(name,head,a,b) \
+ ({ \
+ typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
+ assert(_b); \
+ if (!_a) { \
+ if (!*_head) { \
+ _b->name##_next = NULL; \
+ _b->name##_prev = NULL; \
+ *_head = _b; \
+ } else { \
+ typeof(*(head)) *_tail = (head); \
+ while (_tail->name##_next) \
+ _tail = _tail->name##_next; \
+ _b->name##_next = NULL; \
+ _b->name##_prev = _tail; \
+ _tail->name##_next = _b; \
+ } \
+ } else { \
+ if ((_b->name##_prev = _a->name##_prev)) \
+ _b->name##_prev->name##_next = _b; \
+ else \
+ *_head = _b; \
+ _b->name##_next = _a; \
+ _a->name##_prev = _b; \
+ } \
+ _b; \
+ })
+
+#define LIST_JUST_US(name, item) \
+ ({ \
+ typeof(*(item)) *_item = (item); \
+ !(_item)->name##_prev && !(_item)->name##_next; \
+ })
+
+/* The type of the iterator 'i' is automatically determined by the type of 'head', and declared in the
+ * loop. Hence, do not declare the same variable in the outer scope. Sometimes, we set 'head' through
+ * hashmap_get(). In that case, you need to explicitly cast the result. */
+#define LIST_FOREACH_WITH_NEXT(name,i,n,head) \
+ for (typeof(*(head)) *n, *i = (head); i && (n = i->name##_next, true); i = n)
+
+#define LIST_FOREACH(name,i,head) \
+ LIST_FOREACH_WITH_NEXT(name, i, UNIQ_T(n, UNIQ), head)
+
+#define _LIST_FOREACH_WITH_PREV(name,i,p,start) \
+ for (typeof(*(start)) *p, *i = (start); i && (p = i->name##_prev, true); i = p)
+
+#define LIST_FOREACH_BACKWARDS(name,i,start) \
+ _LIST_FOREACH_WITH_PREV(name, i, UNIQ_T(p, UNIQ), start)
+
+/* Iterate through all the members of the list p is included in, but skip over p */
+#define LIST_FOREACH_OTHERS(name,i,p) \
+ for (typeof(*(p)) *_p = (p), *i = ({ \
+ typeof(*_p) *_j = _p; \
+ while (_j && _j->name##_prev) \
+ _j = _j->name##_prev; \
+ if (_j == _p) \
+ _j = _p->name##_next; \
+ _j; \
+ }); \
+ 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 (typeof(*(p)) *i = (p)->name##_next ? (p)->name##_next : (head); \
+ i != (p); \
+ i = i->name##_next ? i->name##_next : (head))
+
+/* Join two lists tail to head: a->b, c->d to a->b->c->d and de-initialise second list */
+#define LIST_JOIN(name,a,b) \
+ ({ \
+ assert(b); \
+ if (!(a)) \
+ (a) = (b); \
+ else { \
+ typeof(*(a)) *_head = (b), *_tail; \
+ _tail = LIST_FIND_TAIL(name, (a)); \
+ _tail->name##_next = _head; \
+ _head->name##_prev = _tail; \
+ } \
+ (b) = NULL; \
+ a; \
+ })
+
+#define LIST_POP(name, a) \
+ ({ \
+ typeof(a)* _a = &(a); \
+ typeof(a) _p = *_a; \
+ if (_p) \
+ LIST_REMOVE(name, *_a, _p); \
+ _p; \
+ })
+
+#define LIST_CLEAR(name, head, free_func) \
+ _LIST_CLEAR(name, head, free_func, UNIQ_T(elem, UNIQ))
+
+/* Clear the list, destroying each element with free_func */
+#define _LIST_CLEAR(name, head, free_func, elem) \
+ ({ \
+ typeof(head) elem; \
+ while ((elem = LIST_POP(name, head))) \
+ free_func(elem); \
+ head; \
+ })
+
+/* Now include "macro.h", because we want our definition of assert() which the macros above use. We include
+ * it down here instead of up top, since macro.h pulls in log.h which in turn needs our own definitions. */
+#include "macro.h"