From 161c80af5bacf52a9f488551361c25be601eabb9 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Wed, 31 Aug 2016 15:05:22 +0100 Subject: [list] Add list_next_entry() and list_prev_entry() Signed-off-by: Michael Brown --- src/include/ipxe/list.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'src/include') diff --git a/src/include/ipxe/list.h b/src/include/ipxe/list.h index 6a9b76f91..274fb64c6 100644 --- a/src/include/ipxe/list.h +++ b/src/include/ipxe/list.h @@ -348,6 +348,34 @@ extern void extern_list_splice_tail_init ( struct list_head *list, ( type * ) NULL : \ list_entry ( (list)->prev, type, member ) ) +/** + * Get the container of the next entry in a list + * + * @v pos Current list entry + * @v head List head + * @v member Name of list field within iterator's type + * @ret next Next list entry, or NULL at end of list + */ +#define list_next_entry( pos, head, member ) ( { \ + typeof (pos) next = list_entry ( (pos)->member.next, \ + typeof ( *(pos) ), \ + member ); \ + ( ( &next->member == (head) ) ? NULL : next ); } ) + +/** + * Get the container of the previous entry in a list + * + * @v pos Current list entry + * @v head List head + * @v member Name of list field within iterator's type + * @ret next Next list entry, or NULL at end of list + */ +#define list_prev_entry( pos, head, member ) ( { \ + typeof (pos) prev = list_entry ( (pos)->member.prev, \ + typeof ( *(pos) ), \ + member ); \ + ( ( &prev->member == (head) ) ? NULL : prev ); } ) + /** * Iterate over a list * -- cgit v1.2.3-55-g7522