X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftlist%2Ftlist.h;h=a99191a2e0ebd75e9b13145550ac90d0a859f72e;hp=9f62869b2b19c23c3fcb812ed2a6420a45a847a7;hb=03f100b281441a953d4ec858389f82e25a95c043;hpb=be2b527792d574ef8cf506d1a168d92354e23cc5

diff --git a/ccan/tlist/tlist.h b/ccan/tlist/tlist.h
index 9f62869b..a99191a2 100644
--- a/ccan/tlist/tlist.h
+++ b/ccan/tlist/tlist.h
@@ -11,15 +11,16 @@
  *
  * This declares a structure "struct tlist_@suffix" to use for
  * lists containing this type.  The actual list can be accessed using
- * ".raw" or tlist_raw().
+ * ".raw" or tlist_raw().  For maximum portability, place tlists
+ * embedded in structures as the last member.
  *
  * Example:
  *	// Defines struct tlist_children
  *	TLIST_TYPE(children, struct child);
  *	struct parent {
  *		const char *name;
- *		struct tlist_children children;
  *		unsigned int num_children;
+ *		struct tlist_children children;
  *	};
  *
  *	struct child {
@@ -178,32 +179,64 @@
 /**
  * tlist_top - get the first entry in a list
  * @h: the tlist
- * @type: the type of the entry
  * @member: the list_node member of the type
  *
  * If the list is empty, returns NULL.
  *
  * Example:
  *	struct child *first;
- *	first = tlist_top(&parent->children, struct child, list);
+ *	first = tlist_top(&parent->children, list);
+ *	if (!first)
+ *		printf("Empty list!\n");
  */
-#define tlist_top(h, type, member) \
-	list_top(tlist_raw((h), (type *)NULL), type, member)
+#define tlist_top(h, member)						\
+	((tcon_type((h), canary))					\
+	 list_top_(&(h)->raw,						\
+		   (char *)(&(h)->_tcon[0].canary->member) -		\
+		   (char *)((h)->_tcon[0].canary)))
 
 /**
  * tlist_tail - get the last entry in a list
  * @h: the tlist
- * @type: the type of the entry
  * @member: the list_node member of the type
  *
  * If the list is empty, returns NULL.
  *
  * Example:
  *	struct child *last;
- *	last = tlist_tail(&parent->children, struct child, list);
+ *	last = tlist_tail(&parent->children, list);
+ *	if (!last)
+ *		printf("Empty list!\n");
+ */
+#define tlist_tail(h, member)						\
+	((tcon_type((h), canary))					\
+	 list_tail_(&(h)->raw,						\
+		    (char *)(&(h)->_tcon[0].canary->member) -		\
+		    (char *)((h)->_tcon[0].canary)))
+
+/**
+ * tlist_next - get the next entry in a list
+ * @h: the tlist
+ * @n: the list element
+ * @member: the list_node member of the type
+ *
+ * Returns the element of list @h immediately after @n, or NULL, if @n
+ * is the last element in the list.
+ */
+#define tlist_next(h, n, member)					\
+	list_next(tlist_raw((h), (n)), (n), member)
+
+/**
+ * tlist_prev - get the previous entry in a list
+ * @h: the tlist
+ * @n: the list element
+ * @member: the list_node member of the type
+ *
+ * Returns the element of list @h immediately before @n, or NULL, if
+ * @n is the first element in the list.
  */
-#define tlist_tail(h, type, member) \
-	list_tail(tlist_raw((h), (type *)NULL), type, member)
+#define tlist_prev(h, n, member)					\
+	list_prev(tlist_raw((h), (n)), (n), member)
 
 /**
  * tlist_for_each - iterate through a list.
@@ -221,6 +254,22 @@
 #define tlist_for_each(h, i, member)					\
 	list_for_each(tlist_raw((h), (i)), (i), member)
 
+/**
+ * tlist_for_each - iterate through a list backwards.
+ * @h: the tlist
+ * @i: an iterator of suitable type for this list.
+ * @member: the list_node member of @i
+ *
+ * This is a convenient wrapper to iterate @i over the entire list.  It's
+ * a for loop, so you can break and continue as normal.
+ *
+ * Example:
+ *	tlist_for_each_rev(&parent->children, child, list)
+ *		printf("Name: %s\n", child->name);
+ */
+#define tlist_for_each_rev(h, i, member)					\
+	list_for_each_rev(tlist_raw((h), (i)), (i), member)
+
 /**
  * tlist_for_each_safe - iterate through a list, maybe during deletion
  * @h: the tlist