htable: add htable_copy.

[ccan] / ccan / htable / htable.h

diff --git a/ccan/htable/htable.h b/ccan/htable/htable.h
index e150c2ef0958065d3e289482d78dfe8267017a9b..61ed9170fda461779840f63db55295757a9bce8a 100644 (file)
--- a/ccan/htable/htable.h
+++ b/ccan/htable/htable.h
@@ -74,6 +74,25 @@ bool htable_init_sized(struct htable *ht,
  */
 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()