Mesa (master): util: Add list_is_singular() helper function

[Eduardo Lima Mitev]

Module: Mesa
Branch: master
Commit: fb3b5669cee85781b603f612228387e9a2e4120f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=fb3b5669cee85781b603f612228387e9a2e4120f

Author: Eduardo Lima Mitev <elima at igalia.com>
Date:   Fri Oct 23 16:31:41 2015 +0200

util: Add list_is_singular() helper function

Returns whether the list has exactly one element.

Reviewed-by: Matt Turner <mattst88 at gmail.com>

---

 src/util/list.h |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/util/list.h b/src/util/list.h
index b98ce59..066f9b8 100644
--- a/src/util/list.h
+++ b/src/util/list.h
@@ -99,6 +99,14 @@ static inline bool list_empty(struct list_head *list)
    return list->next == list;
 }
 
+/**
+ * Returns whether the list has exactly one element.
+ */
+static inline bool list_is_singular(const struct list_head *list)
+{
+   return list->next != NULL && list->next->next == list;
+}
+
 static inline unsigned list_length(struct list_head *list)
 {
    struct list_head *node;