Birdlib: Modify lists to avoid problems with pointer aliasing rules (54bb032d) · Commits · 戴 / Bird

lib/lists.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -41,7 +41,7 @@ add_tail(list l, node n)
		{
		node *z = l->tail;

		n->next = (node *) &l->null;
		n->next = &l->tail_node;
		n->prev = z;
		z->next = n;
		l->tail = n;
		@@ -60,7 +60,7 @@ add_head(list l, node n)
		node *z = l->head;

		n->next = z;
		n->prev = (node *) &l->head;
		n->prev = &l->head_node;
		z->prev = n;
		l->head = n;
		}
		@@ -133,9 +133,9 @@ replace_node(node old, node new)
		LIST_INLINE void
		init_list(list *l)
		{
		l->head = (node *) &l->null;
		l->head = &l->tail_node;
		l->null = NULL;
		l->tail = (node *) &l->head;
		l->tail = &l->head_node;
		}

		/**
		@@ -155,6 +155,6 @@ add_tail_list(list to, list l)
		p->next = q;
		q->prev = p;
		q = l->tail;
		q->next = (node *) &to->null;
		q->next = &to->tail_node;
		to->tail = q;
		}

+15 −2

Original line number	Diff line number	Diff line
		@@ -26,10 +26,23 @@ typedef struct node {
		struct node next, prev;
		} node;

		typedef struct list { /* In fact two overlayed nodes */
		struct node head, null, *tail;
		typedef union list { /* In fact two overlayed nodes */
		struct { /* Head node */
		struct node head_node;
		void *head_padding;
		};
		struct { /* Tail node */
		void *tail_padding;
		struct node tail_node;
		};
		struct { /* Split to separate pointers */
		struct node *head;
		struct node *null;
		struct node *tail;
		};
		} list;


		#define NODE (node *)
		#define HEAD(list) ((void *)((list).head))
		#define TAIL(list) ((void *)((list).tail))