1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2016 Olaf Wintermann. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "avl.h"
30
31 #define ptrcast(ptr) ((void*)(ptr))
32 #define alloc_tree(al) (UcxAVLTree*) almalloc((al), sizeof(UcxAVLTree))
33 #define alloc_node(al) (UcxAVLNode*) almalloc((al), sizeof(UcxAVLNode))
34
35 static void ucx_avl_connect(UcxAVLTree *tree,
36 UcxAVLNode *node, UcxAVLNode *child, intptr_t nullkey) {
37 if (child) {
38 child->parent = node;
39 }
40 // if child is NULL, nullkey decides if left or right pointer is cleared
41 if (tree->cmpfunc(
42 ptrcast(child ? child->key : nullkey),
43 ptrcast(node->key), tree->userdata) > 0) {
44 node->right = child;
45 } else {
46 node->left = child;
47 }
48 size_t lh = node->left ? node->left->height : 0;
49 size_t rh = node->right ? node->right->height : 0;
50 node->height = 1 + (lh > rh ? lh : rh);
51 }
52
53 #define avlheight(node) ((node) ? (node)->height : 0)
54
55 static UcxAVLNode* avl_rotright(UcxAVLTree *tree, UcxAVLNode *l0) {
56 UcxAVLNode *p = l0->parent;
57 UcxAVLNode *l1 = l0->left;
58 if (p) {
59 ucx_avl_connect(tree, p, l1, 0);
60 } else {
61 l1->parent = NULL;
62 }
63 ucx_avl_connect(tree, l0, l1->right, l1->key);
64 ucx_avl_connect(tree, l1, l0, 0);
65 return l1;
66 }
67
68 static UcxAVLNode* avl_rotleft(UcxAVLTree *tree, UcxAVLNode *l0) {
69 UcxAVLNode *p = l0->parent;
70 UcxAVLNode *l1 = l0->right;
71 if (p) {
72 ucx_avl_connect(tree, p, l1, 0);
73 } else {
74 l1->parent = NULL;
75 }
76 ucx_avl_connect(tree, l0, l1->left, l1->key);
77 ucx_avl_connect(tree, l1, l0, 0);
78 return l1;
79 }
80
81 static void ucx_avl_balance(UcxAVLTree *tree, UcxAVLNode *n) {
82 int lh = avlheight(n->left);
83 int rh = avlheight(n->right);
84 n->height = 1 + (lh > rh ? lh : rh);
85
86 if (lh - rh == 2) {
87 UcxAVLNode *c = n->left;
88 if (avlheight(c->right) - avlheight(c->left) == 1) {
89 avl_rotleft(tree, c);
90 }
91 n = avl_rotright(tree, n);
92 } else if (rh - lh == 2) {
93 UcxAVLNode *c = n->right;
94 if (avlheight(c->left) - avlheight(c->right) == 1) {
95 avl_rotright(tree, c);
96 }
97 n = avl_rotleft(tree, n);
98 }
99
100 if (n->parent) {
101 ucx_avl_balance(tree, n->parent);
102 } else {
103 tree->root = n;
104 }
105 }
106
107 UcxAVLTree *ucx_avl_new(cmp_func cmpfunc) {
108 return ucx_avl_new_a(cmpfunc, ucx_default_allocator());
109 }
110
111 UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator) {
112 UcxAVLTree* tree = alloc_tree(allocator);
113 if (tree) {
114 tree->allocator = allocator;
115 tree->cmpfunc = cmpfunc;
116 tree->root = NULL;
117 tree->userdata = NULL;
118 }
119
120 return tree;
121 }
122
123 static void ucx_avl_free_node(UcxAllocator *al, UcxAVLNode *node) {
124 if (node) {
125 ucx_avl_free_node(al, node->left);
126 ucx_avl_free_node(al, node->right);
127 alfree(al, node);
128 }
129 }
130
131 void ucx_avl_free(UcxAVLTree *tree) {
132 UcxAllocator *al = tree->allocator;
133 ucx_avl_free_node(al, tree->root);
134 alfree(al, tree);
135 }
136
137 UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key) {
138 UcxAVLNode *n = tree->root;
139 int cmpresult;
140 while (n && (cmpresult = tree->cmpfunc(
141 ptrcast(key), ptrcast(n->key), tree->userdata))) {
142 n = cmpresult > 0 ? n->right : n->left;
143 }
144 return n;
145 }
146
147 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key) {
148 UcxAVLNode *n = ucx_avl_get_node(tree, key);
149 return n ? n->value : NULL;
150 }
151
152 int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value) {
153 return ucx_avl_put_s(tree, key, value, NULL);
154 }
155
156 int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value,
157 void **oldvalue) {
158 if (tree->root) {
159 UcxAVLNode *n = tree->root;
160 int cmpresult;
161 while ((cmpresult = tree->cmpfunc(
162 ptrcast(key), ptrcast(n->key), tree->userdata))) {
163 UcxAVLNode *m = cmpresult > 0 ? n->right : n->left;
164 if (m) {
165 n = m;
166 } else {
167 break;
168 }
169 }
170
171 if (cmpresult) {
172 UcxAVLNode* e = alloc_node(tree->allocator);
173 if (e) {
174 e->key = key; e->value = value; e->height = 1;
175 e->parent = e->left = e->right = NULL;
176 ucx_avl_connect(tree, n, e, 0);
177 ucx_avl_balance(tree, n);
178 return 0;
179 } else {
180 return 1;
181 }
182 } else {
183 if (oldvalue) {
184 *oldvalue = n->value;
185 }
186 n->value = value;
187 return 0;
188 }
189 } else {
190 tree->root = alloc_node(tree->allocator);
191 if (tree->root) {
192 tree->root->key = key; tree->root->value = value;
193 tree->root->height = 1;
194 tree->root->parent = tree->root->left = tree->root->right = NULL;
195
196 if (oldvalue) {
197 *oldvalue = NULL;
198 }
199
200 return 0;
201 } else {
202 return 1;
203 }
204 }
205 }
206
207 int ucx_avl_remove(UcxAVLTree *tree, intptr_t key) {
208 return ucx_avl_remove_s(tree, key, NULL, NULL);
209 }
210
211 int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node) {
212 return ucx_avl_remove_s(tree, node->key, NULL, NULL);
213 }
214
215 int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
216 intptr_t *oldkey, void **oldvalue) {
217
218 UcxAVLNode *n = tree->root;
219 int cmpresult;
220 while (n && (cmpresult = tree->cmpfunc(
221 ptrcast(key), ptrcast(n->key), tree->userdata))) {
222 n = cmpresult > 0 ? n->right : n->left;
223 }
224 if (n) {
225 if (oldkey) {
226 *oldkey = n->key;
227 }
228 if (oldvalue) {
229 *oldvalue = n->value;
230 }
231
232 UcxAVLNode *p = n->parent;
233 if (n->left && n->right) {
234 UcxAVLNode *s = n->right;
235 while (s->left) {
236 s = s->left;
237 }
238 ucx_avl_connect(tree, s->parent, s->right, s->key);
239 n->key = s->key; n->value = s->value;
240 p = s->parent;
241 alfree(tree->allocator, s);
242 } else {
243 if (p) {
244 ucx_avl_connect(tree, p, n->right ? n->right:n->left, n->key);
245 } else {
246 tree->root = n->right ? n->right : n->left;
247 if (tree->root) {
248 tree->root->parent = NULL;
249 }
250 }
251 alfree(tree->allocator, n);
252 }
253
254 if (p) {
255 ucx_avl_balance(tree, p);
256 }
257
258 return 0;
259 } else {
260 return 1;
261 }
262 }
263
264 static size_t ucx_avl_countn(UcxAVLNode *node) {
265 if (node) {
266 return 1 + ucx_avl_countn(node->left) + ucx_avl_countn(node->right);
267 } else {
268 return 0;
269 }
270 }
271
272 size_t ucx_avl_count(UcxAVLTree *tree) {
273 return ucx_avl_countn(tree->root);
274 }
275