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
*/
void htable_clear(struct htable *ht);
+/**
+ * htable_copy - duplicate a hash table.
+ * @dst: the hash table to overwrite
+ * @src: the hash table to copy
+ *
+ * Only fails on out-of-memory.
+ *
+ * Equivalent to (but faster than):
+ * if (!htable_init_sized(dst, src->rehash, src->priv, 1U << src->bits))
+ * return false;
+ * v = htable_first(src, &i);
+ * while (v) {
+ * htable_add(dst, v);
+ * v = htable_next(src, i);
+ * }
+ * return true;
+ */
+bool htable_copy(struct htable *dst, const struct htable *src);
+
/**
* htable_rehash - use a hashtree's rehash function
* @elem: the argument to rehash()
*/
void *htable_next(const struct htable *htable, struct htable_iter *i);
+/**
+ * htable_prev - find the previous entry in the hash table
+ * @ht: the hashtable
+ * @i: the struct htable_iter to use
+ *
+ * Get previous entry in the hashtable; NULL if all done.
+ *
+ * "previous" here only means the item that would have been returned by
+ * htable_next() before the item it returned most recently.
+ *
+ * This is usually used in the middle of (or after) a htable_next iteration and
+ * to "unwind" actions taken.
+ */
+void *htable_prev(const struct htable *htable, struct htable_iter *i);
+
/**
* htable_delval - remove an iterated pointer from a hash table
* @ht: the htable