From: Alasdair Kergon <agk@redhat.com>
Date: Thu, 22 Sep 2005 12:06:34 +0000 (+0000)
Subject: Resync list.h with LVM2.
X-Git-Tag: v1_01_05~1
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=c6c58d1c02b1b550a470e4ab406bce38a6582301;p=dm.git

Resync list.h with LVM2.
---

diff --git a/WHATS_NEW b/WHATS_NEW
index 0f1aede..c35bdb5 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 1.01.05 -
 =============================
+  Resync list.h with LVM2.
   Remember increased buffer size and use for subsequent calls.
   On 'buffer full' condition, double buffer size and repeat ioctl.
   Fix termination of getopt_long() option array.
diff --git a/include/list.h b/include/list.h
index 1ec8c73..11765ec 100644
--- a/include/list.h
+++ b/include/list.h
@@ -104,6 +104,22 @@ static inline int list_end(struct list *head, struct list *elem)
 	return elem->n == head;
 }
 
+/*
+ * Return first element of the list or NULL if empty
+ */
+static inline struct list *list_first(struct list *head)
+{
+	return (list_empty(head) ? NULL : head->n);
+}
+
+/*
+ * Return last element of the list or NULL if empty
+ */
+static inline struct list *list_last(struct list *head)
+{
+	return (list_empty(head) ? NULL : head->p);
+}
+
 /*
  * Return the previous element of the list, or NULL if we've reached the start.
  */
@@ -187,6 +203,25 @@ static inline struct list *list_next(struct list *head, struct list *elem)
  */
 #define list_iterate_items(v, head) list_iterate_items_gen(v, (head), list)
 
+/*
+ * Walk a list backwards, setting 'v' in turn to the containing structure 
+ * of each item.
+ * The containing structure should be the same type as 'v'.
+ * The 'struct list' variable within the containing structure is 'field'.
+ */
+#define list_iterate_back_items_gen(v, head, field) \
+	for (v = list_struct_base((head)->p, typeof(*v), field); \
+	     &v->field != (head); \
+	     v = list_struct_base(v->field.p, typeof(*v), field))
+
+/*
+ * Walk a list backwards, setting 'v' in turn to the containing structure 
+ * of each item.
+ * The containing structure should be the same type as 'v'.
+ * The list should be 'struct list list' within the containing structure.
+ */
+#define list_iterate_back_items(v, head) list_iterate_back_items_gen(v, (head), list)
+
 /*
  * Return the number of elements in a list by walking it.
  */