htable: add pre-sized option.

[ccan] / ccan / htable / htable.h

diff --git a/ccan/htable/htable.h b/ccan/htable/htable.h
index ed668e7405ed84e819cec49b85f8186b85287933..03193567d847a5512b31d173bcb8a21a6d54d09e 100644 (file)
--- a/ccan/htable/htable.h
+++ b/ccan/htable/htable.h
@@ -51,6 +51,21 @@ struct htable {
 void htable_init(struct htable *ht,
                 size_t (*rehash)(const void *elem, void *priv), void *priv);
 
+/**
+ * htable_init_sized - initialize an empty hash table of given size.
+ * @ht: the hash table to initialize
+ * @rehash: hash function to use for rehashing.
+ * @priv: private argument to @rehash function.
+ * @size: the number of element.
+ *
+ * If this returns false, @ht is still usable, but may need to do reallocation
+ * upon an add.  If this returns true, it will not need to reallocate within
+ * @size htable_adds.
+ */
+bool htable_init_sized(struct htable *ht,
+                      size_t (*rehash)(const void *elem, void *priv),
+                      void *priv, size_t size);
+
 /**
  * htable_clear - empty a hash table.
  * @ht: the hash table to clear