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comparison: ucx/avl.c

ucx/avl.c

changeset 128
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child 255
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127:7072a2b4ae35 128:649eb328674a
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2015 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
33 static void ucx_avl_connect(UcxAVLTree *tree,
34 UcxAVLNode *node, UcxAVLNode *child, intptr_t nullkey) {
35 if (child) {
36 child->parent = node;
37 }
38 // if child is NULL, nullkey decides if left or right pointer is cleared
39 if (tree->cmpfunc(
40 ptrcast(child ? child->key : nullkey),
41 ptrcast(node->key), tree->userdata) > 0) {
42 node->right = child;
43 } else {
44 node->left = child;
45 }
46 size_t lh = node->left ? node->left->height : 0;
47 size_t rh = node->right ? node->right->height : 0;
48 node->height = 1 + (lh > rh ? lh : rh);
49 }
50
51 #define avlheight(node) ((node) ? (node)->height : 0)
52
53 static UcxAVLNode* avl_rotright(UcxAVLTree *tree, UcxAVLNode *l0) {
54 UcxAVLNode *p = l0->parent;
55 UcxAVLNode *l1 = l0->left;
56 if (p) {
57 ucx_avl_connect(tree, p, l1, 0);
58 } else {
59 l1->parent = NULL;
60 }
61 ucx_avl_connect(tree, l0, l1->right, l1->key);
62 ucx_avl_connect(tree, l1, l0, 0);
63 return l1;
64 }
65
66 static UcxAVLNode* avl_rotleft(UcxAVLTree *tree, UcxAVLNode *l0) {
67 UcxAVLNode *p = l0->parent;
68 UcxAVLNode *l1 = l0->right;
69 if (p) {
70 ucx_avl_connect(tree, p, l1, 0);
71 } else {
72 l1->parent = NULL;
73 }
74 ucx_avl_connect(tree, l0, l1->left, l1->key);
75 ucx_avl_connect(tree, l1, l0, 0);
76 return l1;
77 }
78
79 static void ucx_avl_balance(UcxAVLTree *tree, UcxAVLNode *n) {
80 int lh = avlheight(n->left);
81 int rh = avlheight(n->right);
82 n->height = 1 + (lh > rh ? lh : rh);
83
84 if (lh - rh == 2) {
85 UcxAVLNode *c = n->left;
86 if (avlheight(c->right) - avlheight(c->left) == 1) {
87 avl_rotleft(tree, c);
88 }
89 n = avl_rotright(tree, n);
90 } else if (rh - lh == 2) {
91 UcxAVLNode *c = n->right;
92 if (avlheight(c->left) - avlheight(c->right) == 1) {
93 avl_rotright(tree, c);
94 }
95 n = avl_rotleft(tree, n);
96 }
97
98 if (n->parent) {
99 ucx_avl_balance(tree, n->parent);
100 } else {
101 tree->root = n;
102 }
103 }
104
105 UcxAVLTree *ucx_avl_new(cmp_func cmpfunc) {
106 return ucx_avl_new_a(cmpfunc, ucx_default_allocator());
107 }
108
109 UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator) {
110 UcxAVLTree *tree = almalloc(allocator, sizeof(UcxAVLTree));
111 if (tree) {
112 tree->allocator = allocator;
113 tree->cmpfunc = cmpfunc;
114 tree->root = NULL;
115 tree->userdata = NULL;
116 }
117
118 return tree;
119 }
120
121 static void ucx_avl_free_node(UcxAllocator *al, UcxAVLNode *node) {
122 if (node) {
123 ucx_avl_free_node(al, node->left);
124 ucx_avl_free_node(al, node->right);
125 alfree(al, node);
126 }
127 }
128
129 void ucx_avl_free(UcxAVLTree *tree) {
130 UcxAllocator *al = tree->allocator;
131 ucx_avl_free_node(al, tree->root);
132 alfree(al, tree);
133 }
134
135 UcxAVLNode *ucx_avl_get_node(UcxAVLTree *tree, intptr_t key) {
136 UcxAVLNode *n = tree->root;
137 int cmpresult;
138 while (n && (cmpresult = tree->cmpfunc(
139 ptrcast(key), ptrcast(n->key), tree->userdata))) {
140 n = cmpresult > 0 ? n->right : n->left;
141 }
142 return n;
143 }
144
145 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key) {
146 UcxAVLNode *n = ucx_avl_get_node(tree, key);
147 return n ? n->value : NULL;
148 }
149
150 int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value) {
151 return ucx_avl_put_s(tree, key, value, NULL);
152 }
153
154 int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value,
155 void **oldvalue) {
156 if (tree->root) {
157 UcxAVLNode *n = tree->root;
158 int cmpresult;
159 while ((cmpresult = tree->cmpfunc(
160 ptrcast(key), ptrcast(n->key), tree->userdata))) {
161 UcxAVLNode *m = cmpresult > 0 ? n->right : n->left;
162 if (m) {
163 n = m;
164 } else {
165 break;
166 }
167 }
168
169 if (cmpresult) {
170 UcxAVLNode *e = almalloc(tree->allocator, sizeof(UcxAVLNode));
171 if (e) {
172 e->key = key; e->value = value; e->height = 1;
173 e->parent = e->left = e->right = NULL;
174 ucx_avl_connect(tree, n, e, 0);
175 ucx_avl_balance(tree, n);
176 return 0;
177 } else {
178 return 1;
179 }
180 } else {
181 if (oldvalue) {
182 *oldvalue = n->value;
183 }
184 n->value = value;
185 return 0;
186 }
187 } else {
188 tree->root = almalloc(tree->allocator, sizeof(UcxAVLNode));
189 if (tree->root) {
190 tree->root->key = key; tree->root->value = value;
191 tree->root->height = 1;
192 tree->root->parent = tree->root->left = tree->root->right = NULL;
193
194 if (oldvalue) {
195 *oldvalue = NULL;
196 }
197
198 return 0;
199 } else {
200 return 1;
201 }
202 }
203 }
204
205 int ucx_avl_remove(UcxAVLTree *tree, intptr_t key) {
206 return ucx_avl_remove_s(tree, key, NULL, NULL);
207 }
208
209 int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node) {
210 return ucx_avl_remove_s(tree, node->key, NULL, NULL);
211 }
212
213 int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
214 intptr_t *oldkey, void **oldvalue) {
215
216 UcxAVLNode *n = tree->root;
217 int cmpresult;
218 while (n && (cmpresult = tree->cmpfunc(
219 ptrcast(key), ptrcast(n->key), tree->userdata))) {
220 n = cmpresult > 0 ? n->right : n->left;
221 }
222 if (n) {
223 if (oldkey) {
224 *oldkey = n->key;
225 }
226 if (oldvalue) {
227 *oldvalue = n->value;
228 }
229
230 UcxAVLNode *p = n->parent;
231 if (n->left && n->right) {
232 UcxAVLNode *s = n->right;
233 while (s->left) {
234 s = s->left;
235 }
236 ucx_avl_connect(tree, s->parent, s->right, s->key);
237 n->key = s->key; n->value = s->value;
238 p = s->parent;
239 alfree(tree->allocator, s);
240 } else {
241 if (p) {
242 ucx_avl_connect(tree, p, n->right ? n->right:n->left, n->key);
243 } else {
244 tree->root = n->right ? n->right : n->left;
245 if (tree->root) {
246 tree->root->parent = NULL;
247 }
248 }
249 alfree(tree->allocator, n);
250 }
251
252 if (p) {
253 ucx_avl_balance(tree, p);
254 }
255
256 return 0;
257 } else {
258 return 1;
259 }
260 }
261
262 static size_t ucx_avl_countn(UcxAVLNode *node) {
263 if (node) {
264 return 1 + ucx_avl_countn(node->left) + ucx_avl_countn(node->right);
265 } else {
266 return 0;
267 }
268 }
269
270 size_t ucx_avl_count(UcxAVLTree *tree) {
271 return ucx_avl_countn(tree->root);
272 }

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