htable: htable_pick helper to select a random entry.

[ccan] / ccan / htable / htable_type.h

diff --git a/ccan/htable/htable_type.h b/ccan/htable/htable_type.h
index 9dad4b3927186ab661f6099eeb7e801ed9204277..de4cd471404f1d4f22a4e184366a0efe9934da7c 100644 (file)
--- a/ccan/htable/htable_type.h
+++ b/ccan/htable/htable_type.h
@@ -48,7 +48,8 @@
  *     type *<name>_first(const struct <name> *ht, struct <name>_iter *i);
  *     type *<name>_next(const struct <name> *ht, struct <name>_iter *i);
  *     type *<name>_prev(const struct <name> *ht, struct <name>_iter *i);
- *
+ *      type *<name>_pick(const struct <name> *ht, size_t seed,
+ *                        struct <name>_iter *i);
  * It's currently safe to iterate over a changing hashtable, but you might
  * miss an element.  Iteration isn't very efficient, either.
  *
@@ -146,6 +147,13 @@
                        return name##_del(ht, elem);                    \
                return false;                                           \
        }                                                               \
+       static inline UNNEEDED bool name##_pick(const struct name *ht,  \
+                                               size_t seed,            \
+                                               struct name##_iter *iter) \
+       {                                                               \
+               /* Note &iter->i == NULL iff iter is NULL */            \
+               return htable_pick(&ht->raw, seed, &iter->i);                   \
+       }                                                               \
        static inline UNNEEDED type *name##_first(const struct name *ht, \
                                         struct name##_iter *iter)      \
        {                                                               \