| /* |
| * |
| * Copyright 2015, Google Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #include <grpc/support/avl.h> |
| |
| #include <assert.h> |
| #include <stdlib.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/string_util.h> |
| #include <grpc/support/useful.h> |
| |
| gpr_avl gpr_avl_create(const gpr_avl_vtable *vtable) { |
| gpr_avl out; |
| out.vtable = vtable; |
| out.root = NULL; |
| return out; |
| } |
| |
| static gpr_avl_node *ref_node(gpr_avl_node *node) { |
| if (node) { |
| gpr_ref(&node->refs); |
| } |
| return node; |
| } |
| |
| static void unref_node(const gpr_avl_vtable *vtable, gpr_avl_node *node) { |
| if (node == NULL) { |
| return; |
| } |
| if (gpr_unref(&node->refs)) { |
| vtable->destroy_key(node->key); |
| vtable->destroy_value(node->value); |
| unref_node(vtable, node->left); |
| unref_node(vtable, node->right); |
| gpr_free(node); |
| } |
| } |
| |
| static long node_height(gpr_avl_node *node) { |
| return node == NULL ? 0 : node->height; |
| } |
| |
| #ifndef NDEBUG |
| static long calculate_height(gpr_avl_node *node) { |
| return node == NULL ? 0 : 1 + GPR_MAX(calculate_height(node->left), |
| calculate_height(node->right)); |
| } |
| |
| static gpr_avl_node *assert_invariants(gpr_avl_node *n) { |
| if (n == NULL) return NULL; |
| assert_invariants(n->left); |
| assert_invariants(n->right); |
| assert(calculate_height(n) == n->height); |
| assert(labs(node_height(n->left) - node_height(n->right)) <= 1); |
| return n; |
| } |
| #else |
| static gpr_avl_node *assert_invariants(gpr_avl_node *n) { return n; } |
| #endif |
| |
| gpr_avl_node *new_node(void *key, void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| gpr_avl_node *node = gpr_malloc(sizeof(*node)); |
| gpr_ref_init(&node->refs, 1); |
| node->key = key; |
| node->value = value; |
| node->left = assert_invariants(left); |
| node->right = assert_invariants(right); |
| node->height = 1 + GPR_MAX(node_height(left), node_height(right)); |
| return node; |
| } |
| |
| static gpr_avl_node *get(const gpr_avl_vtable *vtable, gpr_avl_node *node, |
| void *key) { |
| long cmp; |
| |
| if (node == NULL) { |
| return NULL; |
| } |
| |
| cmp = vtable->compare_keys(node->key, key); |
| if (cmp == 0) { |
| return node; |
| } else if (cmp > 0) { |
| return get(vtable, node->left, key); |
| } else { |
| return get(vtable, node->right, key); |
| } |
| } |
| |
| void *gpr_avl_get(gpr_avl avl, void *key) { |
| gpr_avl_node *node = get(avl.vtable, avl.root, key); |
| return node ? node->value : NULL; |
| } |
| |
| static gpr_avl_node *rotate_left(const gpr_avl_vtable *vtable, void *key, |
| void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| gpr_avl_node *n = |
| new_node(vtable->copy_key(right->key), vtable->copy_value(right->value), |
| new_node(key, value, left, ref_node(right->left)), |
| ref_node(right->right)); |
| unref_node(vtable, right); |
| return n; |
| } |
| |
| static gpr_avl_node *rotate_right(const gpr_avl_vtable *vtable, void *key, |
| void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| gpr_avl_node *n = new_node( |
| vtable->copy_key(left->key), vtable->copy_value(left->value), |
| ref_node(left->left), new_node(key, value, ref_node(left->right), right)); |
| unref_node(vtable, left); |
| return n; |
| } |
| |
| static gpr_avl_node *rotate_left_right(const gpr_avl_vtable *vtable, void *key, |
| void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| /* rotate_right(..., rotate_left(left), right) */ |
| gpr_avl_node *n = new_node( |
| vtable->copy_key(left->right->key), |
| vtable->copy_value(left->right->value), |
| new_node(vtable->copy_key(left->key), vtable->copy_value(left->value), |
| ref_node(left->left), ref_node(left->right->left)), |
| new_node(key, value, ref_node(left->right->right), right)); |
| unref_node(vtable, left); |
| return n; |
| } |
| |
| static gpr_avl_node *rotate_right_left(const gpr_avl_vtable *vtable, void *key, |
| void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| /* rotate_left(..., left, rotate_right(right)) */ |
| gpr_avl_node *n = new_node( |
| vtable->copy_key(right->left->key), |
| vtable->copy_value(right->left->value), |
| new_node(key, value, left, ref_node(right->left->left)), |
| new_node(vtable->copy_key(right->key), vtable->copy_key(right->value), |
| ref_node(right->left->right), ref_node(right->right))); |
| unref_node(vtable, right); |
| return n; |
| } |
| |
| static gpr_avl_node *rebalance(const gpr_avl_vtable *vtable, void *key, |
| void *value, gpr_avl_node *left, |
| gpr_avl_node *right) { |
| switch (node_height(left) - node_height(right)) { |
| case 2: |
| if (node_height(left->left) - node_height(left->right) == -1) { |
| return assert_invariants( |
| rotate_left_right(vtable, key, value, left, right)); |
| } else { |
| return assert_invariants(rotate_right(vtable, key, value, left, right)); |
| } |
| case -2: |
| if (node_height(right->left) - node_height(right->right) == 1) { |
| return assert_invariants( |
| rotate_right_left(vtable, key, value, left, right)); |
| } else { |
| return assert_invariants(rotate_left(vtable, key, value, left, right)); |
| } |
| default: |
| return assert_invariants(new_node(key, value, left, right)); |
| } |
| } |
| |
| static gpr_avl_node *add(const gpr_avl_vtable *vtable, gpr_avl_node *node, |
| void *key, void *value) { |
| long cmp; |
| if (node == NULL) { |
| return new_node(key, value, NULL, NULL); |
| } |
| cmp = vtable->compare_keys(node->key, key); |
| if (cmp == 0) { |
| return new_node(key, value, ref_node(node->left), ref_node(node->right)); |
| } else if (cmp > 0) { |
| return rebalance( |
| vtable, vtable->copy_key(node->key), vtable->copy_value(node->value), |
| add(vtable, node->left, key, value), ref_node(node->right)); |
| } else { |
| return rebalance(vtable, vtable->copy_key(node->key), |
| vtable->copy_value(node->value), ref_node(node->left), |
| add(vtable, node->right, key, value)); |
| } |
| } |
| |
| gpr_avl gpr_avl_add(gpr_avl avl, void *key, void *value) { |
| gpr_avl_node *old_root = avl.root; |
| avl.root = add(avl.vtable, avl.root, key, value); |
| assert_invariants(avl.root); |
| unref_node(avl.vtable, old_root); |
| return avl; |
| } |
| |
| static gpr_avl_node *in_order_head(gpr_avl_node *node) { |
| while (node->left != NULL) { |
| node = node->left; |
| } |
| return node; |
| } |
| |
| static gpr_avl_node *in_order_tail(gpr_avl_node *node) { |
| while (node->right != NULL) { |
| node = node->right; |
| } |
| return node; |
| } |
| |
| static gpr_avl_node *remove(const gpr_avl_vtable *vtable, gpr_avl_node *node, |
| void *key) { |
| long cmp; |
| if (node == NULL) { |
| return NULL; |
| } |
| cmp = vtable->compare_keys(node->key, key); |
| if (cmp == 0) { |
| if (node->left == NULL) { |
| return ref_node(node->right); |
| } else if (node->right == NULL) { |
| return ref_node(node->left); |
| } else if (node->left->height < node->right->height) { |
| gpr_avl_node *h = in_order_head(node->right); |
| return rebalance(vtable, vtable->copy_key(h->key), |
| vtable->copy_value(h->value), ref_node(node->left), |
| remove(vtable, node->right, h->key)); |
| } else { |
| gpr_avl_node *h = in_order_tail(node->left); |
| return rebalance( |
| vtable, vtable->copy_key(h->key), vtable->copy_value(h->value), |
| remove(vtable, node->left, h->key), ref_node(node->right)); |
| } |
| } else if (cmp > 0) { |
| return rebalance(vtable, vtable->copy_key(node->key), |
| vtable->copy_value(node->value), |
| remove(vtable, node->left, key), ref_node(node->right)); |
| } else { |
| return rebalance(vtable, vtable->copy_key(node->key), |
| vtable->copy_value(node->value), ref_node(node->left), |
| remove(vtable, node->right, key)); |
| } |
| } |
| |
| gpr_avl gpr_avl_remove(gpr_avl avl, void *key) { |
| gpr_avl_node *old_root = avl.root; |
| avl.root = remove(avl.vtable, avl.root, key); |
| assert_invariants(avl.root); |
| unref_node(avl.vtable, old_root); |
| return avl; |
| } |
| |
| gpr_avl gpr_avl_ref(gpr_avl avl) { |
| ref_node(avl.root); |
| return avl; |
| } |
| |
| void gpr_avl_unref(gpr_avl avl) { unref_node(avl.vtable, avl.root); } |