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authorFlorin Coras <fcoras@cisco.com>2019-04-19 18:50:34 -0700
committerFlorin Coras <fcoras@cisco.com>2019-04-19 19:20:07 -0700
commitf7cda7a9bc399258959084154263c42c5a91e030 (patch)
treef1122bcc6da7b0d7a849092e564479ea124c9cd1
parent51cbbd2282f39ff1b64781c73efbbe3b332ed3d9 (diff)
rbtree: add successor and predecessor functions
Change-Id: I6934beaf5c08bae2d4f0bd3a6bb811810407c1f9 Signed-off-by: Florin Coras <fcoras@cisco.com>
-rw-r--r--src/plugins/unittest/rbtree_test.c58
-rw-r--r--src/vppinfra/rbtree.c34
-rw-r--r--src/vppinfra/rbtree.h2
3 files changed, 90 insertions, 4 deletions
diff --git a/src/plugins/unittest/rbtree_test.c b/src/plugins/unittest/rbtree_test.c
index a20ac1b111b..490be9c156e 100644
--- a/src/plugins/unittest/rbtree_test.c
+++ b/src/plugins/unittest/rbtree_test.c
@@ -41,7 +41,7 @@ rbtree_test_basic (vlib_main_t * vm, unformat_input_t * input)
int __clib_unused verbose, n_keys = 1e3, i;
u32 *test_keys = 0, search_key;
rb_tree_t _rt, *rt = &_rt;
- rb_node_t *n;
+ rb_node_t *n, *aux;
while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
{
@@ -82,13 +82,21 @@ rbtree_test_basic (vlib_main_t * vm, unformat_input_t * input)
RBTREE_TEST (n->key == n_keys / 2, "search result should be %u",
n_keys / 2);
+ aux = rb_tree_successor (rt, n);
+ RBTREE_TEST (aux->key == n_keys / 2 + 1, "successor should be %u is %u",
+ n_keys / 2 + 1, aux->key);
+
+ aux = rb_tree_predecessor (rt, n);
+ RBTREE_TEST (aux->key == n_keys / 2 - 1, "predecessor should be %u is %u",
+ n_keys / 2 - 1, aux->key);
+
n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), n_keys);
RBTREE_TEST (rb_node_is_tnil (rt, n), "search result should be tnil");
/*
* Delete even keys
*/
- for (i = 0; i < (n_keys - 1) / 2; i += 2)
+ for (i = 0; i < n_keys; i += 2)
rb_tree_del (rt, i);
n = rb_tree_max_subtree (rt, rb_node (rt, rt->root));
@@ -99,17 +107,26 @@ rbtree_test_basic (vlib_main_t * vm, unformat_input_t * input)
search_key = 2 * ((n_keys - 1) / 4);
n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), search_key);
- RBTREE_TEST (rb_node_is_tnil (rt, n), "search result should be tnil");
+ RBTREE_TEST (rb_node_is_tnil (rt, n), "search result for %u should be tnil",
+ search_key);
search_key += 1;
n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), search_key);
RBTREE_TEST (n->key == search_key, "search result should be %u",
search_key);
+ aux = rb_tree_successor (rt, n);
+ RBTREE_TEST (aux->key == search_key + 2, "successor should be %u is %u",
+ search_key + 2, aux->key);
+
+ aux = rb_tree_predecessor (rt, n);
+ RBTREE_TEST (aux->key == search_key - 2, "predecessor should be %u is %u",
+ search_key - 2, aux->key);
+
/*
* Re-add even keys
*/
- for (i = 0; i < (n_keys - 1) / 2; i += 2)
+ for (i = 0; i < n_keys; i += 2)
rb_tree_add (rt, i);
RBTREE_TEST (rb_tree_n_nodes (rt) == n_keys + 1, "number nodes %u is %u",
@@ -131,6 +148,14 @@ rbtree_test_basic (vlib_main_t * vm, unformat_input_t * input)
RBTREE_TEST (n->key == search_key, "search result should be %u",
search_key);
+ aux = rb_tree_successor (rt, n);
+ RBTREE_TEST (aux->key == search_key + 1, "successor should be %u is %u",
+ search_key + 1, aux->key);
+
+ aux = rb_tree_predecessor (rt, n);
+ RBTREE_TEST (aux->key == search_key - 1, "predecessor should be %u is %u",
+ search_key - 1, aux->key);
+
/*
* Delete all keys
*/
@@ -150,6 +175,31 @@ rbtree_test_basic (vlib_main_t * vm, unformat_input_t * input)
n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), search_key);
RBTREE_TEST (rb_node_is_tnil (rt, n), "search result should be tnil");
+ /*
+ * Test successor/predecessor
+ */
+ u8 test_vals[] = { 2, 3, 4, 6, 7, 9, 13, 15, 17, 18, 20 };
+ for (i = 0; i < sizeof (test_vals) / sizeof (u8); i++)
+ rb_tree_add (rt, test_vals[i]);
+
+ search_key = 13;
+ n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), search_key);
+ RBTREE_TEST (n->key == search_key, "search result should be %u",
+ search_key);
+
+ aux = rb_tree_successor (rt, n);
+ RBTREE_TEST (aux->key == 15, "successor should be %u is %u", 15, aux->key);
+
+ aux = rb_tree_predecessor (rt, n);
+ RBTREE_TEST (aux->key == 9, "predecessor should be %u is %u", 9, aux->key);
+
+ n = aux;
+ aux = rb_tree_predecessor (rt, n);
+ RBTREE_TEST (aux->key == 7, "predecessor should be %u is %u", 7, aux->key);
+
+ /*
+ * Cleanup
+ */
rb_tree_free_nodes (rt);
RBTREE_TEST (rb_tree_n_nodes (rt) == 0, "number nodes %u is %u",
0, rb_tree_n_nodes (rt));
diff --git a/src/vppinfra/rbtree.c b/src/vppinfra/rbtree.c
index d99367a2c6f..3770c2304ff 100644
--- a/src/vppinfra/rbtree.c
+++ b/src/vppinfra/rbtree.c
@@ -227,6 +227,40 @@ rb_tree_max_subtree (rb_tree_t * rt, rb_node_t * x)
return x;
}
+rb_node_t *
+rb_tree_successor (rb_tree_t * rt, rb_node_t * x)
+{
+ rb_node_t *y;
+
+ if (x->right != RBTREE_TNIL_INDEX)
+ return rb_tree_min_subtree (rt, rb_node_right (rt, x));
+
+ y = rb_node_parent (rt, x);
+ while (!rb_node_is_tnil (rt, y) && y->right == rb_node_index (rt, x))
+ {
+ x = y;
+ y = rb_node_parent (rt, y);
+ }
+ return y;
+}
+
+rb_node_t *
+rb_tree_predecessor (rb_tree_t * rt, rb_node_t * x)
+{
+ rb_node_t *y;
+
+ if (x->left != RBTREE_TNIL_INDEX)
+ return rb_tree_max_subtree (rt, rb_node_left (rt, x));
+
+ y = rb_node_parent (rt, x);
+ while (!rb_node_is_tnil (rt, y) && y->left == rb_node_index (rt, x))
+ {
+ x = y;
+ y = rb_node_parent (rt, y);
+ }
+ return y;
+}
+
static inline void
rb_tree_transplant (rb_tree_t * rt, rb_node_t * u, rb_node_t * v)
{
diff --git a/src/vppinfra/rbtree.h b/src/vppinfra/rbtree.h
index ace07ac5622..73180d1d54c 100644
--- a/src/vppinfra/rbtree.h
+++ b/src/vppinfra/rbtree.h
@@ -54,6 +54,8 @@ u32 rb_tree_n_nodes (rb_tree_t * rt);
rb_node_t *rb_tree_min_subtree (rb_tree_t * rt, rb_node_t * x);
rb_node_t *rb_tree_max_subtree (rb_tree_t * rt, rb_node_t * x);
rb_node_t *rb_tree_search_subtree (rb_tree_t * rt, rb_node_t * x, u32 key);
+rb_node_t *rb_tree_successor (rb_tree_t * rt, rb_node_t * x);
+rb_node_t *rb_tree_predecessor (rb_tree_t * rt, rb_node_t * x);
static inline rb_node_index_t
rb_node_index (rb_tree_t * rt, rb_node_t * n)