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authorFlorin Coras <fcoras@cisco.com>2019-04-15 17:28:51 -0700
committerDave Barach <openvpp@barachs.net>2019-04-16 14:20:34 +0000
commit672d5fc6d36ebc3a3815c4658a8ef3bf256ef044 (patch)
treec2c02d3bb2c97e07c1fcfb665539483b8c53a955 /src
parent2a24987bbaeb30801900a15a7216555b0d4b6e05 (diff)
vppinfra: add basic rbtree
Algorithm from CLRS, Introduction to Algorithms 3rd Edition, Ch. 13 Change-Id: I5bc2c507593770939cd5584f21dacf36ebd2b4c1 Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src')
-rw-r--r--src/plugins/unittest/CMakeLists.txt1
-rw-r--r--src/plugins/unittest/rbtree_test.c202
-rw-r--r--src/vppinfra/CMakeLists.txt2
-rw-r--r--src/vppinfra/rbtree.c411
-rw-r--r--src/vppinfra/rbtree.h84
5 files changed, 700 insertions, 0 deletions
diff --git a/src/plugins/unittest/CMakeLists.txt b/src/plugins/unittest/CMakeLists.txt
index 60a7cc166ab..64ad9a2c486 100644
--- a/src/plugins/unittest/CMakeLists.txt
+++ b/src/plugins/unittest/CMakeLists.txt
@@ -27,6 +27,7 @@ add_vpp_plugin(unittest
interface_test.c
mfib_test.c
punt_test.c
+ rbtree_test.c
session_test.c
string_test.c
tcp_test.c
diff --git a/src/plugins/unittest/rbtree_test.c b/src/plugins/unittest/rbtree_test.c
new file mode 100644
index 00000000000..a20ac1b111b
--- /dev/null
+++ b/src/plugins/unittest/rbtree_test.c
@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <vppinfra/rbtree.h>
+#include <vlib/vlib.h>
+
+#define RBTREE_TEST_I(_cond, _comment, _args...) \
+({ \
+ int _evald = (_cond); \
+ if (!(_evald)) { \
+ fformat(stderr, "FAIL:%d: " _comment "\n", \
+ __LINE__, ##_args); \
+ } else { \
+ fformat(stderr, "PASS:%d: " _comment "\n", \
+ __LINE__, ##_args); \
+ } \
+ _evald; \
+})
+
+#define RBTREE_TEST(_cond, _comment, _args...) \
+{ \
+ if (!RBTREE_TEST_I(_cond, _comment, ##_args)) { \
+ return 1; \
+ } \
+}
+
+static int
+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;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "verbose"))
+ verbose = 1;
+ else if (unformat (input, "nkeys %u", &n_keys))
+ ;
+ else
+ {
+ vlib_cli_output (vm, "parse error: '%U'", format_unformat_error,
+ input);
+ return -1;
+ }
+ }
+
+ rb_tree_init (rt);
+ RBTREE_TEST (rb_tree_n_nodes (rt) == 1, "tnil created");
+
+ /*
+ * Add keys
+ */
+ vec_validate (test_keys, n_keys - 1);
+ for (i = n_keys - 1; i >= 0; i--)
+ {
+ test_keys[i] = i;
+ rb_tree_add (rt, i);
+ }
+
+ RBTREE_TEST (rb_tree_n_nodes (rt) == n_keys + 1, "all nodes added");
+
+ n = rb_tree_max_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == n_keys - 1, "max should be %u", n_keys - 1);
+
+ n = rb_tree_min_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == 0, "min should be %u", 0);
+
+ n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), n_keys / 2);
+ RBTREE_TEST (n->key == n_keys / 2, "search result should be %u",
+ n_keys / 2);
+
+ 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)
+ rb_tree_del (rt, i);
+
+ n = rb_tree_max_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == n_keys - 1, "max should be %u", n_keys - 1);
+
+ n = rb_tree_min_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == 1, "min should be %u and is %u", 1, n->key);
+
+ 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");
+
+ 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);
+
+ /*
+ * Re-add even keys
+ */
+ for (i = 0; i < (n_keys - 1) / 2; i += 2)
+ rb_tree_add (rt, i);
+
+ RBTREE_TEST (rb_tree_n_nodes (rt) == n_keys + 1, "number nodes %u is %u",
+ n_keys + 1, rb_tree_n_nodes (rt));
+
+ n = rb_tree_max_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == n_keys - 1, "max should be %u", n_keys - 1);
+
+ n = rb_tree_min_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (n->key == 0, "min should be %u", 0);
+
+ search_key = 2 * ((n_keys - 1) / 4);
+ 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);
+
+ 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);
+
+ /*
+ * Delete all keys
+ */
+ for (i = 0; i < n_keys; i++)
+ rb_tree_del (rt, i);
+
+ RBTREE_TEST (rb_tree_n_nodes (rt) == 1, "number nodes %u is %u",
+ 1, rb_tree_n_nodes (rt));
+
+ n = rb_tree_min_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (rb_node_is_tnil (rt, n), "min should be tnil");
+
+ n = rb_tree_max_subtree (rt, rb_node (rt, rt->root));
+ RBTREE_TEST (rb_node_is_tnil (rt, n), "max should be tnil");
+
+ 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");
+
+ rb_tree_free_nodes (rt);
+ RBTREE_TEST (rb_tree_n_nodes (rt) == 0, "number nodes %u is %u",
+ 0, rb_tree_n_nodes (rt));
+
+ return 0;
+}
+
+static clib_error_t *
+rbtree_test (vlib_main_t * vm,
+ unformat_input_t * input, vlib_cli_command_t * cmd_arg)
+{
+ int res = 0;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "basic"))
+ {
+ res = rbtree_test_basic (vm, input);
+ }
+ else if (unformat (input, "all"))
+ {
+ if ((res = rbtree_test_basic (vm, input)))
+ goto done;
+ }
+ else
+ break;
+ }
+
+done:
+ if (res)
+ return clib_error_return (0, "rbtree unit test failed");
+ return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (rbtree_test_command, static) =
+{
+ .path = "test rbtree",
+ .short_help = "internal rbtree unit tests",
+ .function = rbtree_test,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vppinfra/CMakeLists.txt b/src/vppinfra/CMakeLists.txt
index df5ca5d407a..702f6fdcae5 100644
--- a/src/vppinfra/CMakeLists.txt
+++ b/src/vppinfra/CMakeLists.txt
@@ -63,6 +63,7 @@ set(VPPINFRA_SRCS
random.c
random_buffer.c
random_isaac.c
+ rbtree.c
serialize.c
slist.c
socket.c
@@ -146,6 +147,7 @@ set(VPPINFRA_HEADERS
random_buffer.h
random.h
random_isaac.h
+ rbtree.h
serialize.h
sha2.h
slist.h
diff --git a/src/vppinfra/rbtree.c b/src/vppinfra/rbtree.c
new file mode 100644
index 00000000000..d99367a2c6f
--- /dev/null
+++ b/src/vppinfra/rbtree.c
@@ -0,0 +1,411 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+ * Algorithm from:
+ * Cormen, T. H., Leiserson, C. E., Rivest, R. L., & Stein, C. (2009).
+ * Introduction to algorithms. MIT press, 3rd Edition, Ch. 13
+ */
+
+#include <vppinfra/rbtree.h>
+
+static inline rb_node_t *
+rb_node_right (rb_tree_t * rt, rb_node_t * n)
+{
+ return pool_elt_at_index (rt->nodes, n->right);
+}
+
+static inline rb_node_t *
+rb_node_left (rb_tree_t * rt, rb_node_t * n)
+{
+ return pool_elt_at_index (rt->nodes, n->left);
+}
+
+static inline rb_node_t *
+rb_node_parent (rb_tree_t * rt, rb_node_t * n)
+{
+ return pool_elt_at_index (rt->nodes, n->parent);
+}
+
+static inline void
+rb_tree_rotate_left (rb_tree_t * rt, rb_node_t * x)
+{
+ rb_node_t *y, *tmp, *xp;
+ rb_node_index_t xi, yi;
+
+ xi = rb_node_index (rt, x);
+ yi = x->right;
+ y = rb_node_right (rt, x);
+ x->right = y->left;
+ if (y->left != RBTREE_TNIL_INDEX)
+ {
+ tmp = rb_node_left (rt, y);
+ tmp->parent = xi;
+ }
+ xp = rb_node_parent (rt, x);
+ y->parent = x->parent;
+ if (x->parent == RBTREE_TNIL_INDEX)
+ rt->root = rb_node_index (rt, y);
+ else if (xp->left == xi)
+ xp->left = yi;
+ else
+ xp->right = yi;
+ y->left = xi;
+ x->parent = yi;
+}
+
+static inline void
+rb_tree_rotate_right (rb_tree_t * rt, rb_node_t * y)
+{
+ rb_node_index_t yi, xi;
+ rb_node_t *x, *yp;
+
+ yi = rb_node_index (rt, y);
+ xi = y->left;
+ x = rb_node_left (rt, y);
+ y->left = x->right;
+ if (x->right != RBTREE_TNIL_INDEX)
+ {
+ rb_node_t *tmp = rb_node_right (rt, x);
+ tmp->parent = yi;
+ }
+ yp = rb_node_parent (rt, y);
+ x->parent = y->parent;
+ if (y->parent == RBTREE_TNIL_INDEX)
+ rt->root = rb_node_index (rt, x);
+ else if (yp->right == yi)
+ yp->right = xi;
+ else
+ yp->left = xi;
+ x->right = yi;
+ y->parent = xi;
+}
+
+static void
+rb_tree_insert (rb_tree_t * rt, rb_node_t * z)
+{
+ rb_node_index_t yi = 0, xi = rt->root, zi;
+ rb_node_t *y, *zpp, *x, *zp;
+
+ y = rb_node (rt, RBTREE_TNIL_INDEX);
+ while (xi != RBTREE_TNIL_INDEX)
+ {
+ x = rb_node (rt, xi);
+ y = x;
+ if (z->key < x->key)
+ xi = x->left;
+ else
+ xi = x->right;
+ }
+ yi = rb_node_index (rt, y);
+ z->parent = yi;
+ if (yi == RBTREE_TNIL_INDEX)
+ rt->root = rb_node_index (rt, z);
+ else if (z->key < y->key)
+ y->left = rb_node_index (rt, z);
+ else
+ y->right = rb_node_index (rt, z);
+
+ /* Tree fixup stage */
+ while (y->color == RBTREE_RED)
+ {
+ zi = rb_node_index (rt, z);
+ zp = rb_node_parent (rt, z);
+ zpp = rb_node_parent (rt, zp);
+ if (z->parent == zpp->left)
+ {
+ y = rb_node_right (rt, zpp);
+ if (y->color == RBTREE_RED)
+ {
+ zp->color = RBTREE_BLACK;
+ y->color = RBTREE_BLACK;
+ zpp->color = RBTREE_RED;
+ z = zpp;
+ }
+ else
+ {
+ if (zi == zp->right)
+ {
+ z = zp;
+ rb_tree_rotate_left (rt, z);
+ zp = rb_node (rt, z->parent);
+ zpp = rb_node (rt, zp->parent);
+ }
+ zp->color = RBTREE_BLACK;
+ zpp->color = RBTREE_RED;
+ rb_tree_rotate_right (rt, zpp);
+ }
+ }
+ else
+ {
+ y = rb_node (rt, zpp->left);
+ if (y->color == RBTREE_RED)
+ {
+ zp->color = RBTREE_BLACK;
+ y->color = RBTREE_BLACK;
+ zpp->color = RBTREE_RED;
+ z = zpp;
+ }
+ else
+ {
+ if (zi == zp->left)
+ {
+ z = zp;
+ rb_tree_rotate_right (rt, z);
+ zp = rb_node (rt, z->parent);
+ zpp = rb_node (rt, zp->parent);
+ }
+ zp->color = RBTREE_BLACK;
+ zpp->color = RBTREE_RED;
+ rb_tree_rotate_left (rt, zpp);
+ }
+ }
+ }
+ rb_node (rt, rt->root)->color = RBTREE_BLACK;
+}
+
+rb_node_index_t
+rb_tree_add (rb_tree_t * rt, u32 key)
+{
+ rb_node_t *n;
+
+ pool_get_zero (rt->nodes, n);
+ n->key = key;
+ n->color = RBTREE_RED;
+ rb_tree_insert (rt, n);
+ return rb_node_index (rt, n);
+}
+
+rb_node_index_t
+rb_tree_add2 (rb_tree_t * rt, u32 key, u32 opaque)
+{
+ rb_node_t *n;
+
+ pool_get_zero (rt->nodes, n);
+ n->key = key;
+ n->color = RBTREE_RED;
+ n->opaque = opaque;
+ rb_tree_insert (rt, n);
+ return rb_node_index (rt, n);
+}
+
+rb_node_t *
+rb_tree_search_subtree (rb_tree_t * rt, rb_node_t * x, u32 key)
+{
+ while (rb_node_index (rt, x) != RBTREE_TNIL_INDEX && key != x->key)
+ if (key < x->key)
+ x = rb_node_left (rt, x);
+ else
+ x = rb_node_right (rt, x);
+ return x;
+}
+
+rb_node_t *
+rb_tree_min_subtree (rb_tree_t * rt, rb_node_t * x)
+{
+ while (x->left != RBTREE_TNIL_INDEX)
+ x = rb_node_left (rt, x);
+ return x;
+}
+
+rb_node_t *
+rb_tree_max_subtree (rb_tree_t * rt, rb_node_t * x)
+{
+ while (x->right != RBTREE_TNIL_INDEX)
+ x = rb_node_right (rt, x);
+ return x;
+}
+
+static inline void
+rb_tree_transplant (rb_tree_t * rt, rb_node_t * u, rb_node_t * v)
+{
+ rb_node_t *up;
+
+ up = rb_node_parent (rt, u);
+ if (u->parent == RBTREE_TNIL_INDEX)
+ rt->root = rb_node_index (rt, v);
+ else if (rb_node_index (rt, u) == up->left)
+ up->left = rb_node_index (rt, v);
+ else
+ up->right = rb_node_index (rt, v);
+ v->parent = u->parent;
+}
+
+void
+rb_tree_del_node (rb_tree_t * rt, rb_node_t * z)
+{
+ rb_node_color_t y_original_color;
+ rb_node_t *x, *y, *yr, *yl, *xp, *w, *wl, *wr;
+ rb_node_index_t xi, yi;
+
+ y = z;
+ y_original_color = y->color;
+
+ if (z->left == RBTREE_TNIL_INDEX)
+ {
+ x = rb_node_right (rt, z);
+ rb_tree_transplant (rt, z, x);
+ }
+ else if (z->right == RBTREE_TNIL_INDEX)
+ {
+ x = rb_node_left (rt, z);
+ rb_tree_transplant (rt, z, x);
+ }
+ else
+ {
+ y = rb_tree_min_subtree (rt, rb_node_right (rt, z));
+ y_original_color = y->color;
+ x = rb_node_right (rt, y);
+ yi = rb_node_index (rt, y);
+ if (y->parent == rb_node_index (rt, z))
+ x->parent = yi;
+ else
+ {
+ rb_tree_transplant (rt, y, rb_node_right (rt, y));
+ y->right = z->right;
+ yr = rb_node_right (rt, y);
+ yr->parent = yi;
+ }
+ rb_tree_transplant (rt, z, y);
+ y->left = z->left;
+ yl = rb_node_left (rt, y);
+ yl->parent = yi;
+ y->color = z->color;
+ }
+
+ if (y_original_color == RBTREE_RED)
+ return;
+
+ /* Tree fixup needed */
+
+ xi = rb_node_index (rt, x);
+ while (xi != rt->root && x->color == RBTREE_BLACK)
+ {
+ xp = rb_node_parent (rt, x);
+ if (xi == xp->left)
+ {
+ w = rb_node_right (rt, xp);
+ if (w->color == RBTREE_RED)
+ {
+ w->color = RBTREE_BLACK;
+ xp->color = RBTREE_RED;
+ rb_tree_rotate_left (rt, xp);
+ w = rb_node_right (rt, xp);
+ }
+ wl = rb_node_left (rt, w);
+ wr = rb_node_right (rt, w);
+ if (wl->color == RBTREE_BLACK && wr->color == RBTREE_BLACK)
+ {
+ w->color = RBTREE_RED;
+ x = xp;
+ }
+ else
+ {
+ if (wr->color == RBTREE_BLACK)
+ {
+ wl->color = RBTREE_BLACK;
+ w->color = RBTREE_RED;
+ rb_tree_rotate_right (rt, w);
+ w = rb_node_right (rt, xp);
+ }
+ w->color = xp->color;
+ xp->color = RBTREE_BLACK;
+ wr->color = RBTREE_BLACK;
+ rb_tree_rotate_left (rt, xp);
+ x = rb_node (rt, rt->root);
+ }
+ }
+ else
+ {
+ w = rb_node_left (rt, xp);
+ if (w->color == RBTREE_RED)
+ {
+ w->color = RBTREE_BLACK;
+ xp->color = RBTREE_RED;
+ rb_tree_rotate_right (rt, xp);
+ w = rb_node_left (rt, xp);
+ }
+ wl = rb_node_left (rt, w);
+ wr = rb_node_right (rt, w);
+ if (wl->color == RBTREE_BLACK && wr->color == RBTREE_BLACK)
+ {
+ w->color = RBTREE_RED;
+ x = xp;
+ }
+ else
+ {
+ if (wl->color == RBTREE_BLACK)
+ {
+ wr->color = RBTREE_BLACK;
+ w->color = RBTREE_RED;
+ rb_tree_rotate_left (rt, w);
+ w = rb_node_left (rt, xp);
+ }
+ w->color = xp->color;
+ xp->color = RBTREE_BLACK;
+ wl->color = RBTREE_BLACK;
+ rb_tree_rotate_right (rt, xp);
+ x = rb_node (rt, rt->root);
+ }
+ }
+ xi = rb_node_index (rt, x);
+ }
+ x->color = RBTREE_BLACK;
+}
+
+void
+rb_tree_del (rb_tree_t * rt, u32 key)
+{
+ rb_node_t *n;
+ n = rb_tree_search_subtree (rt, rb_node (rt, rt->root), key);
+ if (rb_node_index (rt, n) != RBTREE_TNIL_INDEX)
+ {
+ rb_tree_del_node (rt, n);
+ pool_put (rt->nodes, n);
+ }
+}
+
+u32
+rb_tree_n_nodes (rb_tree_t * rt)
+{
+ return pool_elts (rt->nodes);
+}
+
+void
+rb_tree_free_nodes (rb_tree_t * rt)
+{
+ rb_node_t *n;
+ pool_flush (n, rt->nodes,;);
+}
+
+void
+rb_tree_init (rb_tree_t * rt)
+{
+ rb_node_t *tnil;
+
+ rt->nodes = 0;
+ rt->root = RBTREE_TNIL_INDEX;
+
+ /* By convention first node, index 0, is the T.nil sentinel */
+ pool_get_zero (rt->nodes, tnil);
+ tnil->color = RBTREE_BLACK;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vppinfra/rbtree.h b/src/vppinfra/rbtree.h
new file mode 100644
index 00000000000..ace07ac5622
--- /dev/null
+++ b/src/vppinfra/rbtree.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SRC_VPPINFRA_RBTREE_H_
+#define SRC_VPPINFRA_RBTREE_H_
+
+#include <vppinfra/types.h>
+#include <vppinfra/pool.h>
+
+#define RBTREE_TNIL_INDEX 0
+
+typedef u32 rb_node_index_t;
+
+typedef enum rb_tree_color_
+{
+ RBTREE_RED,
+ RBTREE_BLACK
+} rb_node_color_t;
+
+typedef struct rb_node_
+{
+ u8 color; /**< node color */
+ rb_node_index_t parent; /**< parent index */
+ rb_node_index_t left; /**< left child index */
+ rb_node_index_t right; /**< right child index */
+ u32 key; /**< node key */
+ u32 opaque; /**< value stored by node */
+} rb_node_t;
+
+typedef struct rb_tree_
+{
+ rb_node_t *nodes; /**< pool of nodes */
+ rb_node_index_t root; /**< root index */
+} rb_tree_t;
+
+void rb_tree_init (rb_tree_t * rt);
+rb_node_index_t rb_tree_add (rb_tree_t * rt, u32 key);
+rb_node_index_t rb_tree_add2 (rb_tree_t * rt, u32 key, u32 opaque);
+void rb_tree_del (rb_tree_t * rt, u32 key);
+void rb_tree_free_nodes (rb_tree_t * rt);
+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);
+
+static inline rb_node_index_t
+rb_node_index (rb_tree_t * rt, rb_node_t * n)
+{
+ return n - rt->nodes;
+}
+
+static inline u8
+rb_node_is_tnil (rb_tree_t * rt, rb_node_t * n)
+{
+ return rb_node_index (rt, n) == RBTREE_TNIL_INDEX;
+}
+
+static inline rb_node_t *
+rb_node (rb_tree_t * rt, rb_node_index_t ri)
+{
+ return pool_elt_at_index (rt->nodes, ri);
+}
+
+#endif /* SRC_VPPINFRA_RBTREE_H_ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */