hmap: New function hmap_contains().

This is useful in a situation where one knows that an hmap_node is in some
hmap, but it's not certain which one, and one needs to know whether it is
in a particular one.  This is not a very common case; I don't see any
potential users in the current tree, although an upcoming commit will add
one.

Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/lib/hmap.c b/lib/hmap.c
index 9f2774465c3c357b81b4a0086594966e1a72cd11..5862b62783ea56c5b92f7831a1754f98e1af093b 100644 (file)
--- a/lib/hmap.c
+++ b/lib/hmap.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2012 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -261,3 +261,18 @@ hmap_at_position(const struct hmap *hmap,
     *offsetp = 0;
     return NULL;
 }
+
+/* Returns true if 'node' is in 'hmap', false otherwise. */
+bool
+hmap_contains(const struct hmap *hmap, const struct hmap_node *node)
+{
+    struct hmap_node *p;
+
+    for (p = hmap_first_in_bucket(hmap, node->hash); p; p = p->next) {
+        if (p == node) {
+            return true;
+        }
+    }
+
+    return false;
+}

diff --git a/lib/hmap.h b/lib/hmap.h
index ed2d78d34daf8adf286975c52fdceb6c6f72c5dd..246fba2cb976cd25a5a76590e4d5aa00fecca097 100644 (file)
--- a/lib/hmap.h
+++ b/lib/hmap.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2012 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -130,6 +130,8 @@ static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
                                                      size_t hash);
 static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
 
+bool hmap_contains(const struct hmap *, const struct hmap_node *);
+
 /* Iteration. */
 
 /* Iterates through every node in HMAP. */