From 70acbc194fa1cc4972293d4e3affee5ba6fe5539 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Sun, 7 Jan 2024 12:11:04 -0500 Subject: list: New SLIST_HEAD() and SLIST_TAIL() macros --- src/list.h | 43 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 3 deletions(-) (limited to 'src/list.h') diff --git a/src/list.h b/src/list.h index 91f416f..02a7ba2 100644 --- a/src/list.h +++ b/src/list.h @@ -197,14 +197,51 @@ #define SLIST_CHECK_(list) \ (void)sizeof(list->tail - &list->head) +/** + * Get the head of a singly-linked list. + * + * @param list + * The list in question. + * @return + * The first item in the list. + */ +#define SLIST_HEAD(list) \ + SLIST_HEAD_((list)) + +#define SLIST_HEAD_(list) \ + (SLIST_CHECK_(list), list->head) + /** * Check if a singly-linked list is empty. */ #define SLIST_EMPTY(list) \ - SLIST_EMPTY_((list)) + (!SLIST_HEAD(list)) + +/** + * Like container_of(), but using the head pointer instead of offsetof() since + * we don't have the type around. + */ +#define SLIST_CONTAINER_(tail, head, next) \ + (void *)((char *)tail - ((char *)&head->next - (char *)head)) + +/** + * Get the tail of a singly-linked list. + * + * @param list + * The list in question. + * @param node (optional) + * If specified, use item->node.next rather than item->next. + * @return + * The last item in the list. + */ +#define SLIST_TAIL(...) \ + SLIST_TAIL_(__VA_ARGS__, ) + +#define SLIST_TAIL_(list, ...) \ + SLIST_TAIL__((list), LIST_NEXT_(__VA_ARGS__)) -#define SLIST_EMPTY_(list) \ - (SLIST_CHECK_(list), !list->head) +#define SLIST_TAIL__(list, next) \ + (list->head ? SLIST_CONTAINER_(list->tail, list->head, next) : NULL) /** * Check if an item is attached to a singly-linked list. -- cgit v1.2.3