From: Igor Putovny <igor.putovny@nic.cz>
Date: Wed, 17 Jul 2024 12:04:19 +0000 (+0200)
Subject: Add ancestor pointer to enable faster lookup of ancestor with non-null bucket
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9a9f68131a81a66c6e19e386b14d0d03dcbfa181;p=thirdparty%2Fbird.git

Add ancestor pointer to enable faster lookup of ancestor with non-null bucket
---

diff --git a/proto/aggregator/aggregator.c b/proto/aggregator/aggregator.c
index 1644d8d16..441e63f4e 100644
--- a/proto/aggregator/aggregator.c
+++ b/proto/aggregator/aggregator.c
@@ -565,6 +565,9 @@ third_pass(struct trie_node *node)
     assert(node->potential_buckets_count > 0);
     assert(node->potential_buckets[0] != NULL);
     node->bucket = node->potential_buckets[0];
+
+    /* Root is the first node with a bucket */
+    node->ancestor = node;
   }
   else
   {
@@ -572,7 +575,8 @@ third_pass(struct trie_node *node)
     if (!is_leaf(node))
       assert(node->bucket == NULL);
 
-    const struct aggregator_bucket *inherited_bucket = get_ancestor_bucket(node);
+    /* Bucket inherited from the closest ancestor with a non-null bucket */
+    const struct aggregator_bucket *inherited_bucket = node->parent->ancestor->bucket;
 
     /*
      * If bucket inherited from ancestor is one of potential buckets of this node,
@@ -588,6 +592,12 @@ third_pass(struct trie_node *node)
       assert(node->potential_buckets_count > 0);
       node->bucket = node->potential_buckets[0];
     }
+
+    /*
+     * Node with a bucket is the closest ancestor for all his descendants.
+     * Otherwise, it must refer to the closest ancestor of its parent.
+     */
+    node->ancestor = node->bucket ? node : node->parent->ancestor;
   }
 
   /* Preorder traversal */
diff --git a/proto/aggregator/aggregator.h b/proto/aggregator/aggregator.h
index abe6f7d8f..f30d14d43 100644
--- a/proto/aggregator/aggregator.h
+++ b/proto/aggregator/aggregator.h
@@ -111,6 +111,7 @@ struct aggr_item_node {
 struct trie_node {
   struct trie_node *parent;
   struct trie_node *child[2];
+  struct trie_node *ancestor;
   struct aggregator_bucket *bucket;
   struct aggregator_bucket *potential_buckets[MAX_POTENTIAL_BUCKETS_COUNT];
   int potential_buckets_count;