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1 | /* |
1 | /* |
2 | * Copyright (C) 2006 Jakub Jermar |
2 | * Copyright (C) 2006 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | /** |
29 | /** |
30 | * @file btree.c |
30 | * @file btree.c |
31 | * @brief B+tree implementation. |
31 | * @brief B+tree implementation. |
32 | * |
32 | * |
33 | * This file implements B+tree type and operations. |
33 | * This file implements B+tree type and operations. |
34 | * |
34 | * |
35 | * The B+tree has the following properties: |
35 | * The B+tree has the following properties: |
36 | * @li it is a ballanced 3-4-5 tree (i.e. BTREE_M = 5) |
36 | * @li it is a ballanced 3-4-5 tree (i.e. BTREE_M = 5) |
37 | * @li values (i.e. pointers to values) are stored only in leaves |
37 | * @li values (i.e. pointers to values) are stored only in leaves |
38 | * @li leaves are linked in a list |
38 | * @li leaves are linked in a list |
39 | * |
39 | * |
40 | * Be carefull when using these trees. They need to allocate |
40 | * Be carefull when using these trees. They need to allocate |
41 | * and deallocate memory for their index nodes and as such |
41 | * and deallocate memory for their index nodes and as such |
42 | * can sleep. |
42 | * can sleep. |
43 | */ |
43 | */ |
44 | 44 | ||
45 | #include <adt/btree.h> |
45 | #include <adt/btree.h> |
46 | #include <adt/list.h> |
46 | #include <adt/list.h> |
47 | #include <mm/slab.h> |
47 | #include <mm/slab.h> |
48 | #include <debug.h> |
48 | #include <debug.h> |
49 | #include <panic.h> |
49 | #include <panic.h> |
50 | #include <typedefs.h> |
50 | #include <typedefs.h> |
51 | #include <print.h> |
51 | #include <print.h> |
52 | 52 | ||
- | 53 | static void btree_destroy_subtree(btree_node_t *root); |
|
53 | static void _btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *rsubtree, btree_node_t *node); |
54 | static void _btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *rsubtree, btree_node_t *node); |
54 | static void _btree_remove(btree_t *t, btree_key_t key, btree_node_t *node); |
55 | static void _btree_remove(btree_t *t, btree_key_t key, btree_node_t *node); |
55 | static void node_initialize(btree_node_t *node); |
56 | static void node_initialize(btree_node_t *node); |
56 | static void node_insert_key_and_lsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *lsubtree); |
57 | static void node_insert_key_and_lsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *lsubtree); |
57 | static void node_insert_key_and_rsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
58 | static void node_insert_key_and_rsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
58 | static void node_remove_key_and_lsubtree(btree_node_t *node, btree_key_t key); |
59 | static void node_remove_key_and_lsubtree(btree_node_t *node, btree_key_t key); |
59 | static void node_remove_key_and_rsubtree(btree_node_t *node, btree_key_t key); |
60 | static void node_remove_key_and_rsubtree(btree_node_t *node, btree_key_t key); |
60 | static btree_node_t *node_split(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree, btree_key_t *median); |
61 | static btree_node_t *node_split(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree, btree_key_t *median); |
61 | static btree_node_t *node_combine(btree_node_t *node); |
62 | static btree_node_t *node_combine(btree_node_t *node); |
62 | static index_t find_key_by_subtree(btree_node_t *node, btree_node_t *subtree, bool right); |
63 | static index_t find_key_by_subtree(btree_node_t *node, btree_node_t *subtree, bool right); |
63 | static void rotate_from_right(btree_node_t *lnode, btree_node_t *rnode, index_t idx); |
64 | static void rotate_from_right(btree_node_t *lnode, btree_node_t *rnode, index_t idx); |
64 | static void rotate_from_left(btree_node_t *lnode, btree_node_t *rnode, index_t idx); |
65 | static void rotate_from_left(btree_node_t *lnode, btree_node_t *rnode, index_t idx); |
65 | static bool try_insert_by_rotation_to_left(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
66 | static bool try_insert_by_rotation_to_left(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
66 | static bool try_insert_by_rotation_to_right(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
67 | static bool try_insert_by_rotation_to_right(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree); |
67 | static bool try_rotation_from_left(btree_node_t *rnode); |
68 | static bool try_rotation_from_left(btree_node_t *rnode); |
68 | static bool try_rotation_from_right(btree_node_t *lnode); |
69 | static bool try_rotation_from_right(btree_node_t *lnode); |
69 | 70 | ||
70 | #define ROOT_NODE(n) (!(n)->parent) |
71 | #define ROOT_NODE(n) (!(n)->parent) |
71 | #define INDEX_NODE(n) ((n)->subtree[0] != NULL) |
72 | #define INDEX_NODE(n) ((n)->subtree[0] != NULL) |
72 | #define LEAF_NODE(n) ((n)->subtree[0] == NULL) |
73 | #define LEAF_NODE(n) ((n)->subtree[0] == NULL) |
73 | 74 | ||
74 | #define FILL_FACTOR ((BTREE_M-1)/2) |
75 | #define FILL_FACTOR ((BTREE_M-1)/2) |
75 | 76 | ||
76 | #define MEDIAN_LOW_INDEX(n) (((n)->keys-1)/2) |
77 | #define MEDIAN_LOW_INDEX(n) (((n)->keys-1)/2) |
77 | #define MEDIAN_HIGH_INDEX(n) ((n)->keys/2) |
78 | #define MEDIAN_HIGH_INDEX(n) ((n)->keys/2) |
78 | #define MEDIAN_LOW(n) ((n)->key[MEDIAN_LOW_INDEX((n))]); |
79 | #define MEDIAN_LOW(n) ((n)->key[MEDIAN_LOW_INDEX((n))]); |
79 | #define MEDIAN_HIGH(n) ((n)->key[MEDIAN_HIGH_INDEX((n))]); |
80 | #define MEDIAN_HIGH(n) ((n)->key[MEDIAN_HIGH_INDEX((n))]); |
80 | 81 | ||
81 | static slab_cache_t *btree_node_slab; |
82 | static slab_cache_t *btree_node_slab; |
82 | 83 | ||
83 | /** Initialize B-trees. */ |
84 | /** Initialize B-trees. */ |
84 | void btree_init(void) |
85 | void btree_init(void) |
85 | { |
86 | { |
86 | btree_node_slab = slab_cache_create("btree_node_slab", sizeof(btree_node_t), 0, NULL, NULL, SLAB_CACHE_MAGDEFERRED); |
87 | btree_node_slab = slab_cache_create("btree_node_slab", sizeof(btree_node_t), 0, NULL, NULL, SLAB_CACHE_MAGDEFERRED); |
87 | } |
88 | } |
88 | 89 | ||
89 | /** Create empty B-tree. |
90 | /** Create empty B-tree. |
90 | * |
91 | * |
91 | * @param t B-tree. |
92 | * @param t B-tree. |
92 | */ |
93 | */ |
93 | void btree_create(btree_t *t) |
94 | void btree_create(btree_t *t) |
94 | { |
95 | { |
95 | list_initialize(&t->leaf_head); |
96 | list_initialize(&t->leaf_head); |
96 | t->root = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
97 | t->root = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
97 | node_initialize(t->root); |
98 | node_initialize(t->root); |
98 | list_append(&t->root->leaf_link, &t->leaf_head); |
99 | list_append(&t->root->leaf_link, &t->leaf_head); |
99 | } |
100 | } |
100 | 101 | ||
101 | /** Destroy empty B-tree. */ |
102 | /** Destroy empty B-tree. */ |
102 | void btree_destroy(btree_t *t) |
103 | void btree_destroy(btree_t *t) |
103 | { |
104 | { |
104 | ASSERT(!t->root->keys); |
- | |
105 | slab_free(btree_node_slab, t->root); |
105 | btree_destroy_subtree(t->root); |
106 | } |
106 | } |
107 | 107 | ||
108 | /** Insert key-value pair into B-tree. |
108 | /** Insert key-value pair into B-tree. |
109 | * |
109 | * |
110 | * @param t B-tree. |
110 | * @param t B-tree. |
111 | * @param key Key to be inserted. |
111 | * @param key Key to be inserted. |
112 | * @param value Value to be inserted. |
112 | * @param value Value to be inserted. |
113 | * @param leaf_node Leaf node where the insertion should begin. |
113 | * @param leaf_node Leaf node where the insertion should begin. |
114 | */ |
114 | */ |
115 | void btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *leaf_node) |
115 | void btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *leaf_node) |
116 | { |
116 | { |
117 | btree_node_t *lnode; |
117 | btree_node_t *lnode; |
118 | 118 | ||
119 | ASSERT(value); |
119 | ASSERT(value); |
120 | 120 | ||
121 | lnode = leaf_node; |
121 | lnode = leaf_node; |
122 | if (!lnode) { |
122 | if (!lnode) { |
123 | if (btree_search(t, key, &lnode)) { |
123 | if (btree_search(t, key, &lnode)) { |
124 | panic("B-tree %p already contains key %d\n", t, key); |
124 | panic("B-tree %p already contains key %d\n", t, key); |
125 | } |
125 | } |
126 | } |
126 | } |
127 | 127 | ||
128 | _btree_insert(t, key, value, NULL, lnode); |
128 | _btree_insert(t, key, value, NULL, lnode); |
129 | } |
129 | } |
- | 130 | ||
- | 131 | /** Destroy subtree rooted in a node. |
|
- | 132 | * |
|
- | 133 | * @param root Root of the subtree. |
|
- | 134 | */ |
|
- | 135 | void btree_destroy_subtree(btree_node_t *root) |
|
- | 136 | { |
|
- | 137 | int i; |
|
- | 138 | ||
- | 139 | if (root->keys) { |
|
- | 140 | for (i = 0; i < root->keys + 1; i++) { |
|
- | 141 | if (root->subtree[i]) |
|
- | 142 | btree_destroy_subtree(root->subtree[i]); |
|
- | 143 | } |
|
- | 144 | } |
|
- | 145 | slab_free(btree_node_slab, root); |
|
- | 146 | } |
|
130 | 147 | ||
131 | /** Recursively insert into B-tree. |
148 | /** Recursively insert into B-tree. |
132 | * |
149 | * |
133 | * @param t B-tree. |
150 | * @param t B-tree. |
134 | * @param key Key to be inserted. |
151 | * @param key Key to be inserted. |
135 | * @param value Value to be inserted. |
152 | * @param value Value to be inserted. |
136 | * @param rsubtree Right subtree of the inserted key. |
153 | * @param rsubtree Right subtree of the inserted key. |
137 | * @param node Start inserting into this node. |
154 | * @param node Start inserting into this node. |
138 | */ |
155 | */ |
139 | void _btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *rsubtree, btree_node_t *node) |
156 | void _btree_insert(btree_t *t, btree_key_t key, void *value, btree_node_t *rsubtree, btree_node_t *node) |
140 | { |
157 | { |
141 | if (node->keys < BTREE_MAX_KEYS) { |
158 | if (node->keys < BTREE_MAX_KEYS) { |
142 | /* |
159 | /* |
143 | * Node conatins enough space, the key can be stored immediately. |
160 | * Node conatins enough space, the key can be stored immediately. |
144 | */ |
161 | */ |
145 | node_insert_key_and_rsubtree(node, key, value, rsubtree); |
162 | node_insert_key_and_rsubtree(node, key, value, rsubtree); |
146 | } else if (try_insert_by_rotation_to_left(node, key, value, rsubtree)) { |
163 | } else if (try_insert_by_rotation_to_left(node, key, value, rsubtree)) { |
147 | /* |
164 | /* |
148 | * The key-value-rsubtree triplet has been inserted because |
165 | * The key-value-rsubtree triplet has been inserted because |
149 | * some keys could have been moved to the left sibling. |
166 | * some keys could have been moved to the left sibling. |
150 | */ |
167 | */ |
151 | } else if (try_insert_by_rotation_to_right(node, key, value, rsubtree)) { |
168 | } else if (try_insert_by_rotation_to_right(node, key, value, rsubtree)) { |
152 | /* |
169 | /* |
153 | * The key-value-rsubtree triplet has been inserted because |
170 | * The key-value-rsubtree triplet has been inserted because |
154 | * some keys could have been moved to the right sibling. |
171 | * some keys could have been moved to the right sibling. |
155 | */ |
172 | */ |
156 | } else { |
173 | } else { |
157 | btree_node_t *rnode; |
174 | btree_node_t *rnode; |
158 | btree_key_t median; |
175 | btree_key_t median; |
159 | 176 | ||
160 | /* |
177 | /* |
161 | * Node is full and both siblings (if both exist) are full too. |
178 | * Node is full and both siblings (if both exist) are full too. |
162 | * Split the node and insert the smallest key from the node containing |
179 | * Split the node and insert the smallest key from the node containing |
163 | * bigger keys (i.e. the new node) into its parent. |
180 | * bigger keys (i.e. the new node) into its parent. |
164 | */ |
181 | */ |
165 | 182 | ||
166 | rnode = node_split(node, key, value, rsubtree, &median); |
183 | rnode = node_split(node, key, value, rsubtree, &median); |
167 | 184 | ||
168 | if (LEAF_NODE(node)) { |
185 | if (LEAF_NODE(node)) { |
169 | list_prepend(&rnode->leaf_link, &node->leaf_link); |
186 | list_prepend(&rnode->leaf_link, &node->leaf_link); |
170 | } |
187 | } |
171 | 188 | ||
172 | if (ROOT_NODE(node)) { |
189 | if (ROOT_NODE(node)) { |
173 | /* |
190 | /* |
174 | * We split the root node. Create new root. |
191 | * We split the root node. Create new root. |
175 | */ |
192 | */ |
176 | t->root = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
193 | t->root = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
177 | node->parent = t->root; |
194 | node->parent = t->root; |
178 | rnode->parent = t->root; |
195 | rnode->parent = t->root; |
179 | node_initialize(t->root); |
196 | node_initialize(t->root); |
180 | 197 | ||
181 | /* |
198 | /* |
182 | * Left-hand side subtree will be the old root (i.e. node). |
199 | * Left-hand side subtree will be the old root (i.e. node). |
183 | * Right-hand side subtree will be rnode. |
200 | * Right-hand side subtree will be rnode. |
184 | */ |
201 | */ |
185 | t->root->subtree[0] = node; |
202 | t->root->subtree[0] = node; |
186 | 203 | ||
187 | t->root->depth = node->depth + 1; |
204 | t->root->depth = node->depth + 1; |
188 | } |
205 | } |
189 | _btree_insert(t, median, NULL, rnode, node->parent); |
206 | _btree_insert(t, median, NULL, rnode, node->parent); |
190 | } |
207 | } |
191 | 208 | ||
192 | } |
209 | } |
193 | 210 | ||
194 | /** Remove B-tree node. |
211 | /** Remove B-tree node. |
195 | * |
212 | * |
196 | * @param B-tree. |
213 | * @param B-tree. |
197 | * @param key Key to be removed from the B-tree along with its associated value. |
214 | * @param key Key to be removed from the B-tree along with its associated value. |
198 | * @param leaf_node If not NULL, pointer to the leaf node where the key is found. |
215 | * @param leaf_node If not NULL, pointer to the leaf node where the key is found. |
199 | */ |
216 | */ |
200 | void btree_remove(btree_t *t, btree_key_t key, btree_node_t *leaf_node) |
217 | void btree_remove(btree_t *t, btree_key_t key, btree_node_t *leaf_node) |
201 | { |
218 | { |
202 | btree_node_t *lnode; |
219 | btree_node_t *lnode; |
203 | 220 | ||
204 | lnode = leaf_node; |
221 | lnode = leaf_node; |
205 | if (!lnode) { |
222 | if (!lnode) { |
206 | if (!btree_search(t, key, &lnode)) { |
223 | if (!btree_search(t, key, &lnode)) { |
207 | panic("B-tree %p does not contain key %d\n", t, key); |
224 | panic("B-tree %p does not contain key %d\n", t, key); |
208 | } |
225 | } |
209 | } |
226 | } |
210 | 227 | ||
211 | _btree_remove(t, key, lnode); |
228 | _btree_remove(t, key, lnode); |
212 | } |
229 | } |
213 | 230 | ||
214 | /** Recursively remove B-tree node. |
231 | /** Recursively remove B-tree node. |
215 | * |
232 | * |
216 | * @param B-tree. |
233 | * @param B-tree. |
217 | * @param key Key to be removed from the B-tree along with its associated value. |
234 | * @param key Key to be removed from the B-tree along with its associated value. |
218 | * @param node Node where the key being removed resides. |
235 | * @param node Node where the key being removed resides. |
219 | */ |
236 | */ |
220 | void _btree_remove(btree_t *t, btree_key_t key, btree_node_t *node) |
237 | void _btree_remove(btree_t *t, btree_key_t key, btree_node_t *node) |
221 | { |
238 | { |
222 | if (ROOT_NODE(node)) { |
239 | if (ROOT_NODE(node)) { |
223 | if (node->keys == 1 && node->subtree[0]) { |
240 | if (node->keys == 1 && node->subtree[0]) { |
224 | /* |
241 | /* |
225 | * Free the current root and set new root. |
242 | * Free the current root and set new root. |
226 | */ |
243 | */ |
227 | t->root = node->subtree[0]; |
244 | t->root = node->subtree[0]; |
228 | t->root->parent = NULL; |
245 | t->root->parent = NULL; |
229 | slab_free(btree_node_slab, node); |
246 | slab_free(btree_node_slab, node); |
230 | } else { |
247 | } else { |
231 | /* |
248 | /* |
232 | * Remove the key from the root node. |
249 | * Remove the key from the root node. |
233 | * Note that the right subtree is removed because when |
250 | * Note that the right subtree is removed because when |
234 | * combining two nodes, the left-side sibling is preserved |
251 | * combining two nodes, the left-side sibling is preserved |
235 | * and the right-side sibling is freed. |
252 | * and the right-side sibling is freed. |
236 | */ |
253 | */ |
237 | node_remove_key_and_rsubtree(node, key); |
254 | node_remove_key_and_rsubtree(node, key); |
238 | } |
255 | } |
239 | return; |
256 | return; |
240 | } |
257 | } |
241 | 258 | ||
242 | if (node->keys <= FILL_FACTOR) { |
259 | if (node->keys <= FILL_FACTOR) { |
243 | /* |
260 | /* |
244 | * If the node is below the fill factor, |
261 | * If the node is below the fill factor, |
245 | * try to borrow keys from left or right sibling. |
262 | * try to borrow keys from left or right sibling. |
246 | */ |
263 | */ |
247 | if (!try_rotation_from_left(node)) |
264 | if (!try_rotation_from_left(node)) |
248 | try_rotation_from_right(node); |
265 | try_rotation_from_right(node); |
249 | } |
266 | } |
250 | 267 | ||
251 | if (node->keys > FILL_FACTOR) { |
268 | if (node->keys > FILL_FACTOR) { |
252 | int i; |
269 | int i; |
253 | 270 | ||
254 | /* |
271 | /* |
255 | * The key can be immediatelly removed. |
272 | * The key can be immediatelly removed. |
256 | * |
273 | * |
257 | * Note that the right subtree is removed because when |
274 | * Note that the right subtree is removed because when |
258 | * combining two nodes, the left-side sibling is preserved |
275 | * combining two nodes, the left-side sibling is preserved |
259 | * and the right-side sibling is freed. |
276 | * and the right-side sibling is freed. |
260 | */ |
277 | */ |
261 | node_remove_key_and_rsubtree(node, key); |
278 | node_remove_key_and_rsubtree(node, key); |
262 | for (i = 0; i < node->parent->keys; i++) { |
279 | for (i = 0; i < node->parent->keys; i++) { |
263 | if (node->parent->key[i] == key) |
280 | if (node->parent->key[i] == key) |
264 | node->parent->key[i] = node->key[0]; |
281 | node->parent->key[i] = node->key[0]; |
265 | } |
282 | } |
266 | 283 | ||
267 | } else { |
284 | } else { |
268 | index_t idx; |
285 | index_t idx; |
269 | btree_node_t *rnode, *parent; |
286 | btree_node_t *rnode, *parent; |
270 | 287 | ||
271 | /* |
288 | /* |
272 | * The node is below the fill factor as well as its left and right sibling. |
289 | * The node is below the fill factor as well as its left and right sibling. |
273 | * Resort to combining the node with one of its siblings. |
290 | * Resort to combining the node with one of its siblings. |
274 | * The node which is on the left is preserved and the node on the right is |
291 | * The node which is on the left is preserved and the node on the right is |
275 | * freed. |
292 | * freed. |
276 | */ |
293 | */ |
277 | parent = node->parent; |
294 | parent = node->parent; |
278 | node_remove_key_and_rsubtree(node, key); |
295 | node_remove_key_and_rsubtree(node, key); |
279 | rnode = node_combine(node); |
296 | rnode = node_combine(node); |
280 | if (LEAF_NODE(rnode)) |
297 | if (LEAF_NODE(rnode)) |
281 | list_remove(&rnode->leaf_link); |
298 | list_remove(&rnode->leaf_link); |
282 | idx = find_key_by_subtree(parent, rnode, true); |
299 | idx = find_key_by_subtree(parent, rnode, true); |
283 | ASSERT((int) idx != -1); |
300 | ASSERT((int) idx != -1); |
284 | slab_free(btree_node_slab, rnode); |
301 | slab_free(btree_node_slab, rnode); |
285 | _btree_remove(t, parent->key[idx], parent); |
302 | _btree_remove(t, parent->key[idx], parent); |
286 | } |
303 | } |
287 | } |
304 | } |
288 | 305 | ||
289 | /** Search key in a B-tree. |
306 | /** Search key in a B-tree. |
290 | * |
307 | * |
291 | * @param t B-tree. |
308 | * @param t B-tree. |
292 | * @param key Key to be searched. |
309 | * @param key Key to be searched. |
293 | * @param leaf_node Address where to put pointer to visited leaf node. |
310 | * @param leaf_node Address where to put pointer to visited leaf node. |
294 | * |
311 | * |
295 | * @return Pointer to value or NULL if there is no such key. |
312 | * @return Pointer to value or NULL if there is no such key. |
296 | */ |
313 | */ |
297 | void *btree_search(btree_t *t, btree_key_t key, btree_node_t **leaf_node) |
314 | void *btree_search(btree_t *t, btree_key_t key, btree_node_t **leaf_node) |
298 | { |
315 | { |
299 | btree_node_t *cur, *next; |
316 | btree_node_t *cur, *next; |
300 | 317 | ||
301 | /* |
318 | /* |
302 | * Iteratively descend to the leaf that can contain the searched key. |
319 | * Iteratively descend to the leaf that can contain the searched key. |
303 | */ |
320 | */ |
304 | for (cur = t->root; cur; cur = next) { |
321 | for (cur = t->root; cur; cur = next) { |
305 | 322 | ||
306 | /* Last iteration will set this with proper leaf node address. */ |
323 | /* Last iteration will set this with proper leaf node address. */ |
307 | *leaf_node = cur; |
324 | *leaf_node = cur; |
308 | 325 | ||
309 | /* |
326 | /* |
310 | * The key can be in the leftmost subtree. |
327 | * The key can be in the leftmost subtree. |
311 | * Test it separately. |
328 | * Test it separately. |
312 | */ |
329 | */ |
313 | if (key < cur->key[0]) { |
330 | if (key < cur->key[0]) { |
314 | next = cur->subtree[0]; |
331 | next = cur->subtree[0]; |
315 | continue; |
332 | continue; |
316 | } else { |
333 | } else { |
317 | void *val; |
334 | void *val; |
318 | int i; |
335 | int i; |
319 | 336 | ||
320 | /* |
337 | /* |
321 | * Now if the key is smaller than cur->key[i] |
338 | * Now if the key is smaller than cur->key[i] |
322 | * it can only mean that the value is in cur->subtree[i] |
339 | * it can only mean that the value is in cur->subtree[i] |
323 | * or it is not in the tree at all. |
340 | * or it is not in the tree at all. |
324 | */ |
341 | */ |
325 | for (i = 1; i < cur->keys; i++) { |
342 | for (i = 1; i < cur->keys; i++) { |
326 | if (key < cur->key[i]) { |
343 | if (key < cur->key[i]) { |
327 | next = cur->subtree[i]; |
344 | next = cur->subtree[i]; |
328 | val = cur->value[i - 1]; |
345 | val = cur->value[i - 1]; |
329 | 346 | ||
330 | if (LEAF_NODE(cur)) |
347 | if (LEAF_NODE(cur)) |
331 | return key == cur->key[i - 1] ? val : NULL; |
348 | return key == cur->key[i - 1] ? val : NULL; |
332 | 349 | ||
333 | goto descend; |
350 | goto descend; |
334 | } |
351 | } |
335 | } |
352 | } |
336 | 353 | ||
337 | /* |
354 | /* |
338 | * Last possibility is that the key is in the rightmost subtree. |
355 | * Last possibility is that the key is in the rightmost subtree. |
339 | */ |
356 | */ |
340 | next = cur->subtree[i]; |
357 | next = cur->subtree[i]; |
341 | val = cur->value[i - 1]; |
358 | val = cur->value[i - 1]; |
342 | if (LEAF_NODE(cur)) |
359 | if (LEAF_NODE(cur)) |
343 | return key == cur->key[i - 1] ? val : NULL; |
360 | return key == cur->key[i - 1] ? val : NULL; |
344 | } |
361 | } |
345 | descend: |
362 | descend: |
346 | ; |
363 | ; |
347 | } |
364 | } |
348 | 365 | ||
349 | /* |
366 | /* |
350 | * The key was not found in the *leaf_node and is smaller than any of its keys. |
367 | * The key was not found in the *leaf_node and is smaller than any of its keys. |
351 | */ |
368 | */ |
352 | return NULL; |
369 | return NULL; |
353 | } |
370 | } |
354 | 371 | ||
355 | /** Return pointer to B-tree leaf node's left neighbour. |
372 | /** Return pointer to B-tree leaf node's left neighbour. |
356 | * |
373 | * |
357 | * @param t B-tree. |
374 | * @param t B-tree. |
358 | * @param node Node whose left neighbour will be returned. |
375 | * @param node Node whose left neighbour will be returned. |
359 | * |
376 | * |
360 | * @return Left neighbour of the node or NULL if the node does not have the left neighbour. |
377 | * @return Left neighbour of the node or NULL if the node does not have the left neighbour. |
361 | */ |
378 | */ |
362 | btree_node_t *btree_leaf_node_left_neighbour(btree_t *t, btree_node_t *node) |
379 | btree_node_t *btree_leaf_node_left_neighbour(btree_t *t, btree_node_t *node) |
363 | { |
380 | { |
364 | ASSERT(LEAF_NODE(node)); |
381 | ASSERT(LEAF_NODE(node)); |
365 | if (node->leaf_link.prev != &t->leaf_head) |
382 | if (node->leaf_link.prev != &t->leaf_head) |
366 | return list_get_instance(node->leaf_link.prev, btree_node_t, leaf_link); |
383 | return list_get_instance(node->leaf_link.prev, btree_node_t, leaf_link); |
367 | else |
384 | else |
368 | return NULL; |
385 | return NULL; |
369 | } |
386 | } |
370 | 387 | ||
371 | /** Return pointer to B-tree leaf node's right neighbour. |
388 | /** Return pointer to B-tree leaf node's right neighbour. |
372 | * |
389 | * |
373 | * @param t B-tree. |
390 | * @param t B-tree. |
374 | * @param node Node whose right neighbour will be returned. |
391 | * @param node Node whose right neighbour will be returned. |
375 | * |
392 | * |
376 | * @return Right neighbour of the node or NULL if the node does not have the right neighbour. |
393 | * @return Right neighbour of the node or NULL if the node does not have the right neighbour. |
377 | */ |
394 | */ |
378 | btree_node_t *btree_leaf_node_right_neighbour(btree_t *t, btree_node_t *node) |
395 | btree_node_t *btree_leaf_node_right_neighbour(btree_t *t, btree_node_t *node) |
379 | { |
396 | { |
380 | ASSERT(LEAF_NODE(node)); |
397 | ASSERT(LEAF_NODE(node)); |
381 | if (node->leaf_link.next != &t->leaf_head) |
398 | if (node->leaf_link.next != &t->leaf_head) |
382 | return list_get_instance(node->leaf_link.next, btree_node_t, leaf_link); |
399 | return list_get_instance(node->leaf_link.next, btree_node_t, leaf_link); |
383 | else |
400 | else |
384 | return NULL; |
401 | return NULL; |
385 | } |
402 | } |
386 | 403 | ||
387 | /** Initialize B-tree node. |
404 | /** Initialize B-tree node. |
388 | * |
405 | * |
389 | * @param node B-tree node. |
406 | * @param node B-tree node. |
390 | */ |
407 | */ |
391 | void node_initialize(btree_node_t *node) |
408 | void node_initialize(btree_node_t *node) |
392 | { |
409 | { |
393 | int i; |
410 | int i; |
394 | 411 | ||
395 | node->keys = 0; |
412 | node->keys = 0; |
396 | 413 | ||
397 | /* Clean also space for the extra key. */ |
414 | /* Clean also space for the extra key. */ |
398 | for (i = 0; i < BTREE_MAX_KEYS + 1; i++) { |
415 | for (i = 0; i < BTREE_MAX_KEYS + 1; i++) { |
399 | node->key[i] = 0; |
416 | node->key[i] = 0; |
400 | node->value[i] = NULL; |
417 | node->value[i] = NULL; |
401 | node->subtree[i] = NULL; |
418 | node->subtree[i] = NULL; |
402 | } |
419 | } |
403 | node->subtree[i] = NULL; |
420 | node->subtree[i] = NULL; |
404 | 421 | ||
405 | node->parent = NULL; |
422 | node->parent = NULL; |
406 | 423 | ||
407 | link_initialize(&node->leaf_link); |
424 | link_initialize(&node->leaf_link); |
408 | 425 | ||
409 | link_initialize(&node->bfs_link); |
426 | link_initialize(&node->bfs_link); |
410 | node->depth = 0; |
427 | node->depth = 0; |
411 | } |
428 | } |
412 | 429 | ||
413 | /** Insert key-value-lsubtree triplet into B-tree node. |
430 | /** Insert key-value-lsubtree triplet into B-tree node. |
414 | * |
431 | * |
415 | * It is actually possible to have more keys than BTREE_MAX_KEYS. |
432 | * It is actually possible to have more keys than BTREE_MAX_KEYS. |
416 | * This feature is used during insert by right rotation. |
433 | * This feature is used during insert by right rotation. |
417 | * |
434 | * |
418 | * @param node B-tree node into wich the new key is to be inserted. |
435 | * @param node B-tree node into wich the new key is to be inserted. |
419 | * @param key The key to be inserted. |
436 | * @param key The key to be inserted. |
420 | * @param value Pointer to value to be inserted. |
437 | * @param value Pointer to value to be inserted. |
421 | * @param lsubtree Pointer to the left subtree. |
438 | * @param lsubtree Pointer to the left subtree. |
422 | */ |
439 | */ |
423 | void node_insert_key_and_lsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *lsubtree) |
440 | void node_insert_key_and_lsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *lsubtree) |
424 | { |
441 | { |
425 | int i; |
442 | int i; |
426 | 443 | ||
427 | for (i = 0; i < node->keys; i++) { |
444 | for (i = 0; i < node->keys; i++) { |
428 | if (key < node->key[i]) { |
445 | if (key < node->key[i]) { |
429 | int j; |
446 | int j; |
430 | 447 | ||
431 | for (j = node->keys; j > i; j--) { |
448 | for (j = node->keys; j > i; j--) { |
432 | node->key[j] = node->key[j - 1]; |
449 | node->key[j] = node->key[j - 1]; |
433 | node->value[j] = node->value[j - 1]; |
450 | node->value[j] = node->value[j - 1]; |
434 | node->subtree[j + 1] = node->subtree[j]; |
451 | node->subtree[j + 1] = node->subtree[j]; |
435 | } |
452 | } |
436 | node->subtree[j + 1] = node->subtree[j]; |
453 | node->subtree[j + 1] = node->subtree[j]; |
437 | break; |
454 | break; |
438 | } |
455 | } |
439 | } |
456 | } |
440 | node->key[i] = key; |
457 | node->key[i] = key; |
441 | node->value[i] = value; |
458 | node->value[i] = value; |
442 | node->subtree[i] = lsubtree; |
459 | node->subtree[i] = lsubtree; |
443 | 460 | ||
444 | node->keys++; |
461 | node->keys++; |
445 | } |
462 | } |
446 | 463 | ||
447 | /** Insert key-value-rsubtree triplet into B-tree node. |
464 | /** Insert key-value-rsubtree triplet into B-tree node. |
448 | * |
465 | * |
449 | * It is actually possible to have more keys than BTREE_MAX_KEYS. |
466 | * It is actually possible to have more keys than BTREE_MAX_KEYS. |
450 | * This feature is used during splitting the node when the |
467 | * This feature is used during splitting the node when the |
451 | * number of keys is BTREE_MAX_KEYS + 1. Insert by left rotation |
468 | * number of keys is BTREE_MAX_KEYS + 1. Insert by left rotation |
452 | * also makes use of this feature. |
469 | * also makes use of this feature. |
453 | * |
470 | * |
454 | * @param node B-tree node into wich the new key is to be inserted. |
471 | * @param node B-tree node into wich the new key is to be inserted. |
455 | * @param key The key to be inserted. |
472 | * @param key The key to be inserted. |
456 | * @param value Pointer to value to be inserted. |
473 | * @param value Pointer to value to be inserted. |
457 | * @param rsubtree Pointer to the right subtree. |
474 | * @param rsubtree Pointer to the right subtree. |
458 | */ |
475 | */ |
459 | void node_insert_key_and_rsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree) |
476 | void node_insert_key_and_rsubtree(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree) |
460 | { |
477 | { |
461 | int i; |
478 | int i; |
462 | 479 | ||
463 | for (i = 0; i < node->keys; i++) { |
480 | for (i = 0; i < node->keys; i++) { |
464 | if (key < node->key[i]) { |
481 | if (key < node->key[i]) { |
465 | int j; |
482 | int j; |
466 | 483 | ||
467 | for (j = node->keys; j > i; j--) { |
484 | for (j = node->keys; j > i; j--) { |
468 | node->key[j] = node->key[j - 1]; |
485 | node->key[j] = node->key[j - 1]; |
469 | node->value[j] = node->value[j - 1]; |
486 | node->value[j] = node->value[j - 1]; |
470 | node->subtree[j + 1] = node->subtree[j]; |
487 | node->subtree[j + 1] = node->subtree[j]; |
471 | } |
488 | } |
472 | break; |
489 | break; |
473 | } |
490 | } |
474 | } |
491 | } |
475 | node->key[i] = key; |
492 | node->key[i] = key; |
476 | node->value[i] = value; |
493 | node->value[i] = value; |
477 | node->subtree[i + 1] = rsubtree; |
494 | node->subtree[i + 1] = rsubtree; |
478 | 495 | ||
479 | node->keys++; |
496 | node->keys++; |
480 | } |
497 | } |
481 | 498 | ||
482 | /** Remove key and its left subtree pointer from B-tree node. |
499 | /** Remove key and its left subtree pointer from B-tree node. |
483 | * |
500 | * |
484 | * Remove the key and eliminate gaps in node->key array. |
501 | * Remove the key and eliminate gaps in node->key array. |
485 | * Note that the value pointer and the left subtree pointer |
502 | * Note that the value pointer and the left subtree pointer |
486 | * is removed from the node as well. |
503 | * is removed from the node as well. |
487 | * |
504 | * |
488 | * @param node B-tree node. |
505 | * @param node B-tree node. |
489 | * @param key Key to be removed. |
506 | * @param key Key to be removed. |
490 | */ |
507 | */ |
491 | void node_remove_key_and_lsubtree(btree_node_t *node, btree_key_t key) |
508 | void node_remove_key_and_lsubtree(btree_node_t *node, btree_key_t key) |
492 | { |
509 | { |
493 | int i, j; |
510 | int i, j; |
494 | 511 | ||
495 | for (i = 0; i < node->keys; i++) { |
512 | for (i = 0; i < node->keys; i++) { |
496 | if (key == node->key[i]) { |
513 | if (key == node->key[i]) { |
497 | for (j = i + 1; j < node->keys; j++) { |
514 | for (j = i + 1; j < node->keys; j++) { |
498 | node->key[j - 1] = node->key[j]; |
515 | node->key[j - 1] = node->key[j]; |
499 | node->value[j - 1] = node->value[j]; |
516 | node->value[j - 1] = node->value[j]; |
500 | node->subtree[j - 1] = node->subtree[j]; |
517 | node->subtree[j - 1] = node->subtree[j]; |
501 | } |
518 | } |
502 | node->subtree[j - 1] = node->subtree[j]; |
519 | node->subtree[j - 1] = node->subtree[j]; |
503 | node->keys--; |
520 | node->keys--; |
504 | return; |
521 | return; |
505 | } |
522 | } |
506 | } |
523 | } |
507 | panic("node %p does not contain key %d\n", node, key); |
524 | panic("node %p does not contain key %d\n", node, key); |
508 | } |
525 | } |
509 | 526 | ||
510 | /** Remove key and its right subtree pointer from B-tree node. |
527 | /** Remove key and its right subtree pointer from B-tree node. |
511 | * |
528 | * |
512 | * Remove the key and eliminate gaps in node->key array. |
529 | * Remove the key and eliminate gaps in node->key array. |
513 | * Note that the value pointer and the right subtree pointer |
530 | * Note that the value pointer and the right subtree pointer |
514 | * is removed from the node as well. |
531 | * is removed from the node as well. |
515 | * |
532 | * |
516 | * @param node B-tree node. |
533 | * @param node B-tree node. |
517 | * @param key Key to be removed. |
534 | * @param key Key to be removed. |
518 | */ |
535 | */ |
519 | void node_remove_key_and_rsubtree(btree_node_t *node, btree_key_t key) |
536 | void node_remove_key_and_rsubtree(btree_node_t *node, btree_key_t key) |
520 | { |
537 | { |
521 | int i, j; |
538 | int i, j; |
522 | 539 | ||
523 | for (i = 0; i < node->keys; i++) { |
540 | for (i = 0; i < node->keys; i++) { |
524 | if (key == node->key[i]) { |
541 | if (key == node->key[i]) { |
525 | for (j = i + 1; j < node->keys; j++) { |
542 | for (j = i + 1; j < node->keys; j++) { |
526 | node->key[j - 1] = node->key[j]; |
543 | node->key[j - 1] = node->key[j]; |
527 | node->value[j - 1] = node->value[j]; |
544 | node->value[j - 1] = node->value[j]; |
528 | node->subtree[j] = node->subtree[j + 1]; |
545 | node->subtree[j] = node->subtree[j + 1]; |
529 | } |
546 | } |
530 | node->keys--; |
547 | node->keys--; |
531 | return; |
548 | return; |
532 | } |
549 | } |
533 | } |
550 | } |
534 | panic("node %p does not contain key %d\n", node, key); |
551 | panic("node %p does not contain key %d\n", node, key); |
535 | } |
552 | } |
536 | 553 | ||
537 | /** Split full B-tree node and insert new key-value-right-subtree triplet. |
554 | /** Split full B-tree node and insert new key-value-right-subtree triplet. |
538 | * |
555 | * |
539 | * This function will split a node and return pointer to a newly created |
556 | * This function will split a node and return pointer to a newly created |
540 | * node containing keys greater than or equal to the greater of medians |
557 | * node containing keys greater than or equal to the greater of medians |
541 | * (or median) of the old keys and the newly added key. It will also write |
558 | * (or median) of the old keys and the newly added key. It will also write |
542 | * the median key to a memory address supplied by the caller. |
559 | * the median key to a memory address supplied by the caller. |
543 | * |
560 | * |
544 | * If the node being split is an index node, the median will not be |
561 | * If the node being split is an index node, the median will not be |
545 | * included in the new node. If the node is a leaf node, |
562 | * included in the new node. If the node is a leaf node, |
546 | * the median will be copied there. |
563 | * the median will be copied there. |
547 | * |
564 | * |
548 | * @param node B-tree node wich is going to be split. |
565 | * @param node B-tree node wich is going to be split. |
549 | * @param key The key to be inserted. |
566 | * @param key The key to be inserted. |
550 | * @param value Pointer to the value to be inserted. |
567 | * @param value Pointer to the value to be inserted. |
551 | * @param rsubtree Pointer to the right subtree of the key being added. |
568 | * @param rsubtree Pointer to the right subtree of the key being added. |
552 | * @param median Address in memory, where the median key will be stored. |
569 | * @param median Address in memory, where the median key will be stored. |
553 | * |
570 | * |
554 | * @return Newly created right sibling of node. |
571 | * @return Newly created right sibling of node. |
555 | */ |
572 | */ |
556 | btree_node_t *node_split(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree, btree_key_t *median) |
573 | btree_node_t *node_split(btree_node_t *node, btree_key_t key, void *value, btree_node_t *rsubtree, btree_key_t *median) |
557 | { |
574 | { |
558 | btree_node_t *rnode; |
575 | btree_node_t *rnode; |
559 | int i, j; |
576 | int i, j; |
560 | 577 | ||
561 | ASSERT(median); |
578 | ASSERT(median); |
562 | ASSERT(node->keys == BTREE_MAX_KEYS); |
579 | ASSERT(node->keys == BTREE_MAX_KEYS); |
563 | 580 | ||
564 | /* |
581 | /* |
565 | * Use the extra space to store the extra node. |
582 | * Use the extra space to store the extra node. |
566 | */ |
583 | */ |
567 | node_insert_key_and_rsubtree(node, key, value, rsubtree); |
584 | node_insert_key_and_rsubtree(node, key, value, rsubtree); |
568 | 585 | ||
569 | /* |
586 | /* |
570 | * Compute median of keys. |
587 | * Compute median of keys. |
571 | */ |
588 | */ |
572 | *median = MEDIAN_HIGH(node); |
589 | *median = MEDIAN_HIGH(node); |
573 | 590 | ||
574 | /* |
591 | /* |
575 | * Allocate and initialize new right sibling. |
592 | * Allocate and initialize new right sibling. |
576 | */ |
593 | */ |
577 | rnode = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
594 | rnode = (btree_node_t *) slab_alloc(btree_node_slab, 0); |
578 | node_initialize(rnode); |
595 | node_initialize(rnode); |
579 | rnode->parent = node->parent; |
596 | rnode->parent = node->parent; |
580 | rnode->depth = node->depth; |
597 | rnode->depth = node->depth; |
581 | 598 | ||
582 | /* |
599 | /* |
583 | * Copy big keys, values and subtree pointers to the new right sibling. |
600 | * Copy big keys, values and subtree pointers to the new right sibling. |
584 | * If this is an index node, do not copy the median. |
601 | * If this is an index node, do not copy the median. |
585 | */ |
602 | */ |
586 | i = (int) INDEX_NODE(node); |
603 | i = (int) INDEX_NODE(node); |
587 | for (i += MEDIAN_HIGH_INDEX(node), j = 0; i < node->keys; i++, j++) { |
604 | for (i += MEDIAN_HIGH_INDEX(node), j = 0; i < node->keys; i++, j++) { |
588 | rnode->key[j] = node->key[i]; |
605 | rnode->key[j] = node->key[i]; |
589 | rnode->value[j] = node->value[i]; |
606 | rnode->value[j] = node->value[i]; |
590 | rnode->subtree[j] = node->subtree[i]; |
607 | rnode->subtree[j] = node->subtree[i]; |
591 | 608 | ||
592 | /* |
609 | /* |
593 | * Fix parent links in subtrees. |
610 | * Fix parent links in subtrees. |
594 | */ |
611 | */ |
595 | if (rnode->subtree[j]) |
612 | if (rnode->subtree[j]) |
596 | rnode->subtree[j]->parent = rnode; |
613 | rnode->subtree[j]->parent = rnode; |
597 | 614 | ||
598 | } |
615 | } |
599 | rnode->subtree[j] = node->subtree[i]; |
616 | rnode->subtree[j] = node->subtree[i]; |
600 | if (rnode->subtree[j]) |
617 | if (rnode->subtree[j]) |
601 | rnode->subtree[j]->parent = rnode; |
618 | rnode->subtree[j]->parent = rnode; |
602 | 619 | ||
603 | rnode->keys = j; /* Set number of keys of the new node. */ |
620 | rnode->keys = j; /* Set number of keys of the new node. */ |
604 | node->keys /= 2; /* Shrink the old node. */ |
621 | node->keys /= 2; /* Shrink the old node. */ |
605 | 622 | ||
606 | return rnode; |
623 | return rnode; |
607 | } |
624 | } |
608 | 625 | ||
609 | /** Combine node with any of its siblings. |
626 | /** Combine node with any of its siblings. |
610 | * |
627 | * |
611 | * The siblings are required to be below the fill factor. |
628 | * The siblings are required to be below the fill factor. |
612 | * |
629 | * |
613 | * @param node Node to combine with one of its siblings. |
630 | * @param node Node to combine with one of its siblings. |
614 | * |
631 | * |
615 | * @return Pointer to the rightmost of the two nodes. |
632 | * @return Pointer to the rightmost of the two nodes. |
616 | */ |
633 | */ |
617 | btree_node_t *node_combine(btree_node_t *node) |
634 | btree_node_t *node_combine(btree_node_t *node) |
618 | { |
635 | { |
619 | index_t idx; |
636 | index_t idx; |
620 | btree_node_t *rnode; |
637 | btree_node_t *rnode; |
621 | int i; |
638 | int i; |
622 | 639 | ||
623 | ASSERT(!ROOT_NODE(node)); |
640 | ASSERT(!ROOT_NODE(node)); |
624 | 641 | ||
625 | idx = find_key_by_subtree(node->parent, node, false); |
642 | idx = find_key_by_subtree(node->parent, node, false); |
626 | if (idx == node->parent->keys) { |
643 | if (idx == node->parent->keys) { |
627 | /* |
644 | /* |
628 | * Rightmost subtree of its parent, combine with the left sibling. |
645 | * Rightmost subtree of its parent, combine with the left sibling. |
629 | */ |
646 | */ |
630 | idx--; |
647 | idx--; |
631 | rnode = node; |
648 | rnode = node; |
632 | node = node->parent->subtree[idx]; |
649 | node = node->parent->subtree[idx]; |
633 | } else { |
650 | } else { |
634 | rnode = node->parent->subtree[idx + 1]; |
651 | rnode = node->parent->subtree[idx + 1]; |
635 | } |
652 | } |
636 | 653 | ||
637 | /* Index nodes need to insert parent node key in between left and right node. */ |
654 | /* Index nodes need to insert parent node key in between left and right node. */ |
638 | if (INDEX_NODE(node)) |
655 | if (INDEX_NODE(node)) |
639 | node->key[node->keys++] = node->parent->key[idx]; |
656 | node->key[node->keys++] = node->parent->key[idx]; |
640 | 657 | ||
641 | /* Copy the key-value-subtree triplets from the right node. */ |
658 | /* Copy the key-value-subtree triplets from the right node. */ |
642 | for (i = 0; i < rnode->keys; i++) { |
659 | for (i = 0; i < rnode->keys; i++) { |
643 | node->key[node->keys + i] = rnode->key[i]; |
660 | node->key[node->keys + i] = rnode->key[i]; |
644 | node->value[node->keys + i] = rnode->value[i]; |
661 | node->value[node->keys + i] = rnode->value[i]; |
645 | if (INDEX_NODE(node)) { |
662 | if (INDEX_NODE(node)) { |
646 | node->subtree[node->keys + i] = rnode->subtree[i]; |
663 | node->subtree[node->keys + i] = rnode->subtree[i]; |
647 | rnode->subtree[i]->parent = node; |
664 | rnode->subtree[i]->parent = node; |
648 | } |
665 | } |
649 | } |
666 | } |
650 | if (INDEX_NODE(node)) { |
667 | if (INDEX_NODE(node)) { |
651 | node->subtree[node->keys + i] = rnode->subtree[i]; |
668 | node->subtree[node->keys + i] = rnode->subtree[i]; |
652 | rnode->subtree[i]->parent = node; |
669 | rnode->subtree[i]->parent = node; |
653 | } |
670 | } |
654 | 671 | ||
655 | node->keys += rnode->keys; |
672 | node->keys += rnode->keys; |
656 | 673 | ||
657 | return rnode; |
674 | return rnode; |
658 | } |
675 | } |
659 | 676 | ||
660 | /** Find key by its left or right subtree. |
677 | /** Find key by its left or right subtree. |
661 | * |
678 | * |
662 | * @param node B-tree node. |
679 | * @param node B-tree node. |
663 | * @param subtree Left or right subtree of a key found in node. |
680 | * @param subtree Left or right subtree of a key found in node. |
664 | * @param right If true, subtree is a right subtree. If false, subtree is a left subtree. |
681 | * @param right If true, subtree is a right subtree. If false, subtree is a left subtree. |
665 | * |
682 | * |
666 | * @return Index of the key associated with the subtree. |
683 | * @return Index of the key associated with the subtree. |
667 | */ |
684 | */ |
668 | index_t find_key_by_subtree(btree_node_t *node, btree_node_t *subtree, bool right) |
685 | index_t find_key_by_subtree(btree_node_t *node, btree_node_t *subtree, bool right) |
669 | { |
686 | { |
670 | int i; |
687 | int i; |
671 | 688 | ||
672 | for (i = 0; i < node->keys + 1; i++) { |
689 | for (i = 0; i < node->keys + 1; i++) { |
673 | if (subtree == node->subtree[i]) |
690 | if (subtree == node->subtree[i]) |
674 | return i - (int) (right != false); |
691 | return i - (int) (right != false); |
675 | } |
692 | } |
676 | panic("node %p does not contain subtree %p\n", node, subtree); |
693 | panic("node %p does not contain subtree %p\n", node, subtree); |
677 | } |
694 | } |
678 | 695 | ||
679 | /** Rotate one key-value-rsubtree triplet from the left sibling to the right sibling. |
696 | /** Rotate one key-value-rsubtree triplet from the left sibling to the right sibling. |
680 | * |
697 | * |
681 | * The biggest key and its value and right subtree is rotated from the left node |
698 | * The biggest key and its value and right subtree is rotated from the left node |
682 | * to the right. If the node is an index node, than the parent node key belonging to |
699 | * to the right. If the node is an index node, than the parent node key belonging to |
683 | * the left node takes part in the rotation. |
700 | * the left node takes part in the rotation. |
684 | * |
701 | * |
685 | * @param lnode Left sibling. |
702 | * @param lnode Left sibling. |
686 | * @param rnode Right sibling. |
703 | * @param rnode Right sibling. |
687 | * @param idx Index of the parent node key that is taking part in the rotation. |
704 | * @param idx Index of the parent node key that is taking part in the rotation. |
688 | */ |
705 | */ |
689 | void rotate_from_left(btree_node_t *lnode, btree_node_t *rnode, index_t idx) |
706 | void rotate_from_left(btree_node_t *lnode, btree_node_t *rnode, index_t idx) |
690 | { |
707 | { |
691 | btree_key_t key; |
708 | btree_key_t key; |
692 | 709 | ||
693 | key = lnode->key[lnode->keys - 1]; |
710 | key = lnode->key[lnode->keys - 1]; |
694 | 711 | ||
695 | if (LEAF_NODE(lnode)) { |
712 | if (LEAF_NODE(lnode)) { |
696 | void *value; |
713 | void *value; |
697 | 714 | ||
698 | value = lnode->value[lnode->keys - 1]; |
715 | value = lnode->value[lnode->keys - 1]; |
699 | node_remove_key_and_rsubtree(lnode, key); |
716 | node_remove_key_and_rsubtree(lnode, key); |
700 | node_insert_key_and_lsubtree(rnode, key, value, NULL); |
717 | node_insert_key_and_lsubtree(rnode, key, value, NULL); |
701 | lnode->parent->key[idx] = key; |
718 | lnode->parent->key[idx] = key; |
702 | } else { |
719 | } else { |
703 | btree_node_t *rsubtree; |
720 | btree_node_t *rsubtree; |
704 | 721 | ||
705 | rsubtree = lnode->subtree[lnode->keys]; |
722 | rsubtree = lnode->subtree[lnode->keys]; |
706 | node_remove_key_and_rsubtree(lnode, key); |
723 | node_remove_key_and_rsubtree(lnode, key); |
707 | node_insert_key_and_lsubtree(rnode, lnode->parent->key[idx], NULL, rsubtree); |
724 | node_insert_key_and_lsubtree(rnode, lnode->parent->key[idx], NULL, rsubtree); |
708 | lnode->parent->key[idx] = key; |
725 | lnode->parent->key[idx] = key; |
709 | 726 | ||
710 | /* Fix parent link of the reconnected right subtree. */ |
727 | /* Fix parent link of the reconnected right subtree. */ |
711 | rsubtree->parent = rnode; |
728 | rsubtree->parent = rnode; |
712 | } |
729 | } |
713 | 730 | ||
714 | } |
731 | } |
715 | 732 | ||
716 | /** Rotate one key-value-lsubtree triplet from the right sibling to the left sibling. |
733 | /** Rotate one key-value-lsubtree triplet from the right sibling to the left sibling. |
717 | * |
734 | * |
718 | * The smallest key and its value and left subtree is rotated from the right node |
735 | * The smallest key and its value and left subtree is rotated from the right node |
719 | * to the left. If the node is an index node, than the parent node key belonging to |
736 | * to the left. If the node is an index node, than the parent node key belonging to |
720 | * the right node takes part in the rotation. |
737 | * the right node takes part in the rotation. |
721 | * |
738 | * |
722 | * @param lnode Left sibling. |
739 | * @param lnode Left sibling. |
723 | * @param rnode Right sibling. |
740 | * @param rnode Right sibling. |
724 | * @param idx Index of the parent node key that is taking part in the rotation. |
741 | * @param idx Index of the parent node key that is taking part in the rotation. |
725 | */ |
742 | */ |
726 | void rotate_from_right(btree_node_t *lnode, btree_node_t *rnode, index_t idx) |
743 | void rotate_from_right(btree_node_t *lnode, btree_node_t *rnode, index_t idx) |
727 | { |
744 | { |
728 | btree_key_t key; |
745 | btree_key_t key; |
729 | 746 | ||
730 | key = rnode->key[0]; |
747 | key = rnode->key[0]; |
731 | 748 | ||
732 | if (LEAF_NODE(rnode)) { |
749 | if (LEAF_NODE(rnode)) { |
733 | void *value; |
750 | void *value; |
734 | 751 | ||
735 | value = rnode->value[0]; |
752 | value = rnode->value[0]; |
736 | node_remove_key_and_lsubtree(rnode, key); |
753 | node_remove_key_and_lsubtree(rnode, key); |
737 | node_insert_key_and_rsubtree(lnode, key, value, NULL); |
754 | node_insert_key_and_rsubtree(lnode, key, value, NULL); |
738 | rnode->parent->key[idx] = rnode->key[0]; |
755 | rnode->parent->key[idx] = rnode->key[0]; |
739 | } else { |
756 | } else { |
740 | btree_node_t *lsubtree; |
757 | btree_node_t *lsubtree; |
741 | 758 | ||
742 | lsubtree = rnode->subtree[0]; |
759 | lsubtree = rnode->subtree[0]; |
743 | node_remove_key_and_lsubtree(rnode, key); |
760 | node_remove_key_and_lsubtree(rnode, key); |
744 | node_insert_key_and_rsubtree(lnode, rnode->parent->key[idx], NULL, lsubtree); |
761 | node_insert_key_and_rsubtree(lnode, rnode->parent->key[idx], NULL, lsubtree); |
745 | rnode->parent->key[idx] = key; |
762 | rnode->parent->key[idx] = key; |
746 | 763 | ||
747 | /* Fix parent link of the reconnected left subtree. */ |
764 | /* Fix parent link of the reconnected left subtree. */ |
748 | lsubtree->parent = lnode; |
765 | lsubtree->parent = lnode; |
749 | } |
766 | } |
750 | 767 | ||
751 | } |
768 | } |
752 | 769 | ||
753 | /** Insert key-value-rsubtree triplet and rotate the node to the left, if this operation can be done. |
770 | /** Insert key-value-rsubtree triplet and rotate the node to the left, if this operation can be done. |
754 | * |
771 | * |
755 | * Left sibling of the node (if it exists) is checked for free space. |
772 | * Left sibling of the node (if it exists) is checked for free space. |
756 | * If there is free space, the key is inserted and the smallest key of |
773 | * If there is free space, the key is inserted and the smallest key of |
757 | * the node is moved there. The index node which is the parent of both |
774 | * the node is moved there. The index node which is the parent of both |
758 | * nodes is fixed. |
775 | * nodes is fixed. |
759 | * |
776 | * |
760 | * @param node B-tree node. |
777 | * @param node B-tree node. |
761 | * @param inskey Key to be inserted. |
778 | * @param inskey Key to be inserted. |
762 | * @param insvalue Value to be inserted. |
779 | * @param insvalue Value to be inserted. |
763 | * @param rsubtree Right subtree of inskey. |
780 | * @param rsubtree Right subtree of inskey. |
764 | * |
781 | * |
765 | * @return True if the rotation was performed, false otherwise. |
782 | * @return True if the rotation was performed, false otherwise. |
766 | */ |
783 | */ |
767 | bool try_insert_by_rotation_to_left(btree_node_t *node, btree_key_t inskey, void *insvalue, btree_node_t *rsubtree) |
784 | bool try_insert_by_rotation_to_left(btree_node_t *node, btree_key_t inskey, void *insvalue, btree_node_t *rsubtree) |
768 | { |
785 | { |
769 | index_t idx; |
786 | index_t idx; |
770 | btree_node_t *lnode; |
787 | btree_node_t *lnode; |
771 | 788 | ||
772 | /* |
789 | /* |
773 | * If this is root node, the rotation can not be done. |
790 | * If this is root node, the rotation can not be done. |
774 | */ |
791 | */ |
775 | if (ROOT_NODE(node)) |
792 | if (ROOT_NODE(node)) |
776 | return false; |
793 | return false; |
777 | 794 | ||
778 | idx = find_key_by_subtree(node->parent, node, true); |
795 | idx = find_key_by_subtree(node->parent, node, true); |
779 | if ((int) idx == -1) { |
796 | if ((int) idx == -1) { |
780 | /* |
797 | /* |
781 | * If this node is the leftmost subtree of its parent, |
798 | * If this node is the leftmost subtree of its parent, |
782 | * the rotation can not be done. |
799 | * the rotation can not be done. |
783 | */ |
800 | */ |
784 | return false; |
801 | return false; |
785 | } |
802 | } |
786 | 803 | ||
787 | lnode = node->parent->subtree[idx]; |
804 | lnode = node->parent->subtree[idx]; |
788 | if (lnode->keys < BTREE_MAX_KEYS) { |
805 | if (lnode->keys < BTREE_MAX_KEYS) { |
789 | /* |
806 | /* |
790 | * The rotaion can be done. The left sibling has free space. |
807 | * The rotaion can be done. The left sibling has free space. |
791 | */ |
808 | */ |
792 | node_insert_key_and_rsubtree(node, inskey, insvalue, rsubtree); |
809 | node_insert_key_and_rsubtree(node, inskey, insvalue, rsubtree); |
793 | rotate_from_right(lnode, node, idx); |
810 | rotate_from_right(lnode, node, idx); |
794 | return true; |
811 | return true; |
795 | } |
812 | } |
796 | 813 | ||
797 | return false; |
814 | return false; |
798 | } |
815 | } |
799 | 816 | ||
800 | /** Insert key-value-rsubtree triplet and rotate the node to the right, if this operation can be done. |
817 | /** Insert key-value-rsubtree triplet and rotate the node to the right, if this operation can be done. |
801 | * |
818 | * |
802 | * Right sibling of the node (if it exists) is checked for free space. |
819 | * Right sibling of the node (if it exists) is checked for free space. |
803 | * If there is free space, the key is inserted and the biggest key of |
820 | * If there is free space, the key is inserted and the biggest key of |
804 | * the node is moved there. The index node which is the parent of both |
821 | * the node is moved there. The index node which is the parent of both |
805 | * nodes is fixed. |
822 | * nodes is fixed. |
806 | * |
823 | * |
807 | * @param node B-tree node. |
824 | * @param node B-tree node. |
808 | * @param inskey Key to be inserted. |
825 | * @param inskey Key to be inserted. |
809 | * @param insvalue Value to be inserted. |
826 | * @param insvalue Value to be inserted. |
810 | * @param rsubtree Right subtree of inskey. |
827 | * @param rsubtree Right subtree of inskey. |
811 | * |
828 | * |
812 | * @return True if the rotation was performed, false otherwise. |
829 | * @return True if the rotation was performed, false otherwise. |
813 | */ |
830 | */ |
814 | bool try_insert_by_rotation_to_right(btree_node_t *node, btree_key_t inskey, void *insvalue, btree_node_t *rsubtree) |
831 | bool try_insert_by_rotation_to_right(btree_node_t *node, btree_key_t inskey, void *insvalue, btree_node_t *rsubtree) |
815 | { |
832 | { |
816 | index_t idx; |
833 | index_t idx; |
817 | btree_node_t *rnode; |
834 | btree_node_t *rnode; |
818 | 835 | ||
819 | /* |
836 | /* |
820 | * If this is root node, the rotation can not be done. |
837 | * If this is root node, the rotation can not be done. |
821 | */ |
838 | */ |
822 | if (ROOT_NODE(node)) |
839 | if (ROOT_NODE(node)) |
823 | return false; |
840 | return false; |
824 | 841 | ||
825 | idx = find_key_by_subtree(node->parent, node, false); |
842 | idx = find_key_by_subtree(node->parent, node, false); |
826 | if (idx == node->parent->keys) { |
843 | if (idx == node->parent->keys) { |
827 | /* |
844 | /* |
828 | * If this node is the rightmost subtree of its parent, |
845 | * If this node is the rightmost subtree of its parent, |
829 | * the rotation can not be done. |
846 | * the rotation can not be done. |
830 | */ |
847 | */ |
831 | return false; |
848 | return false; |
832 | } |
849 | } |
833 | 850 | ||
834 | rnode = node->parent->subtree[idx + 1]; |
851 | rnode = node->parent->subtree[idx + 1]; |
835 | if (rnode->keys < BTREE_MAX_KEYS) { |
852 | if (rnode->keys < BTREE_MAX_KEYS) { |
836 | /* |
853 | /* |
837 | * The rotaion can be done. The right sibling has free space. |
854 | * The rotaion can be done. The right sibling has free space. |
838 | */ |
855 | */ |
839 | node_insert_key_and_rsubtree(node, inskey, insvalue, rsubtree); |
856 | node_insert_key_and_rsubtree(node, inskey, insvalue, rsubtree); |
840 | rotate_from_left(node, rnode, idx); |
857 | rotate_from_left(node, rnode, idx); |
841 | return true; |
858 | return true; |
842 | } |
859 | } |
843 | 860 | ||
844 | return false; |
861 | return false; |
845 | } |
862 | } |
846 | 863 | ||
847 | /** Rotate in a key from the left sibling or from the index node, if this operation can be done. |
864 | /** Rotate in a key from the left sibling or from the index node, if this operation can be done. |
848 | * |
865 | * |
849 | * @param rnode Node into which to add key from its left sibling or from the index node. |
866 | * @param rnode Node into which to add key from its left sibling or from the index node. |
850 | * |
867 | * |
851 | * @return True if the rotation was performed, false otherwise. |
868 | * @return True if the rotation was performed, false otherwise. |
852 | */ |
869 | */ |
853 | bool try_rotation_from_left(btree_node_t *rnode) |
870 | bool try_rotation_from_left(btree_node_t *rnode) |
854 | { |
871 | { |
855 | index_t idx; |
872 | index_t idx; |
856 | btree_node_t *lnode; |
873 | btree_node_t *lnode; |
857 | 874 | ||
858 | /* |
875 | /* |
859 | * If this is root node, the rotation can not be done. |
876 | * If this is root node, the rotation can not be done. |
860 | */ |
877 | */ |
861 | if (ROOT_NODE(rnode)) |
878 | if (ROOT_NODE(rnode)) |
862 | return false; |
879 | return false; |
863 | 880 | ||
864 | idx = find_key_by_subtree(rnode->parent, rnode, true); |
881 | idx = find_key_by_subtree(rnode->parent, rnode, true); |
865 | if ((int) idx == -1) { |
882 | if ((int) idx == -1) { |
866 | /* |
883 | /* |
867 | * If this node is the leftmost subtree of its parent, |
884 | * If this node is the leftmost subtree of its parent, |
868 | * the rotation can not be done. |
885 | * the rotation can not be done. |
869 | */ |
886 | */ |
870 | return false; |
887 | return false; |
871 | } |
888 | } |
872 | 889 | ||
873 | lnode = rnode->parent->subtree[idx]; |
890 | lnode = rnode->parent->subtree[idx]; |
874 | if (lnode->keys > FILL_FACTOR) { |
891 | if (lnode->keys > FILL_FACTOR) { |
875 | rotate_from_left(lnode, rnode, idx); |
892 | rotate_from_left(lnode, rnode, idx); |
876 | return true; |
893 | return true; |
877 | } |
894 | } |
878 | 895 | ||
879 | return false; |
896 | return false; |
880 | } |
897 | } |
881 | 898 | ||
882 | /** Rotate in a key from the right sibling or from the index node, if this operation can be done. |
899 | /** Rotate in a key from the right sibling or from the index node, if this operation can be done. |
883 | * |
900 | * |
884 | * @param rnode Node into which to add key from its right sibling or from the index node. |
901 | * @param rnode Node into which to add key from its right sibling or from the index node. |
885 | * |
902 | * |
886 | * @return True if the rotation was performed, false otherwise. |
903 | * @return True if the rotation was performed, false otherwise. |
887 | */ |
904 | */ |
888 | bool try_rotation_from_right(btree_node_t *lnode) |
905 | bool try_rotation_from_right(btree_node_t *lnode) |
889 | { |
906 | { |
890 | index_t idx; |
907 | index_t idx; |
891 | btree_node_t *rnode; |
908 | btree_node_t *rnode; |
892 | 909 | ||
893 | /* |
910 | /* |
894 | * If this is root node, the rotation can not be done. |
911 | * If this is root node, the rotation can not be done. |
895 | */ |
912 | */ |
896 | if (ROOT_NODE(lnode)) |
913 | if (ROOT_NODE(lnode)) |
897 | return false; |
914 | return false; |
898 | 915 | ||
899 | idx = find_key_by_subtree(lnode->parent, lnode, false); |
916 | idx = find_key_by_subtree(lnode->parent, lnode, false); |
900 | if (idx == lnode->parent->keys) { |
917 | if (idx == lnode->parent->keys) { |
901 | /* |
918 | /* |
902 | * If this node is the rightmost subtree of its parent, |
919 | * If this node is the rightmost subtree of its parent, |
903 | * the rotation can not be done. |
920 | * the rotation can not be done. |
904 | */ |
921 | */ |
905 | return false; |
922 | return false; |
906 | } |
923 | } |
907 | 924 | ||
908 | rnode = lnode->parent->subtree[idx + 1]; |
925 | rnode = lnode->parent->subtree[idx + 1]; |
909 | if (rnode->keys > FILL_FACTOR) { |
926 | if (rnode->keys > FILL_FACTOR) { |
910 | rotate_from_right(lnode, rnode, idx); |
927 | rotate_from_right(lnode, rnode, idx); |
911 | return true; |
928 | return true; |
912 | } |
929 | } |
913 | 930 | ||
914 | return false; |
931 | return false; |
915 | } |
932 | } |
916 | 933 | ||
917 | /** Print B-tree. |
934 | /** Print B-tree. |
918 | * |
935 | * |
919 | * @param t Print out B-tree. |
936 | * @param t Print out B-tree. |
920 | */ |
937 | */ |
921 | void btree_print(btree_t *t) |
938 | void btree_print(btree_t *t) |
922 | { |
939 | { |
923 | int i, depth = t->root->depth; |
940 | int i, depth = t->root->depth; |
924 | link_t head, *cur; |
941 | link_t head, *cur; |
925 | 942 | ||
926 | printf("Printing B-tree:\n"); |
943 | printf("Printing B-tree:\n"); |
927 | list_initialize(&head); |
944 | list_initialize(&head); |
928 | list_append(&t->root->bfs_link, &head); |
945 | list_append(&t->root->bfs_link, &head); |
929 | 946 | ||
930 | /* |
947 | /* |
931 | * Use BFS search to print out the tree. |
948 | * Use BFS search to print out the tree. |
932 | * Levels are distinguished from one another by node->depth. |
949 | * Levels are distinguished from one another by node->depth. |
933 | */ |
950 | */ |
934 | while (!list_empty(&head)) { |
951 | while (!list_empty(&head)) { |
935 | link_t *hlp; |
952 | link_t *hlp; |
936 | btree_node_t *node; |
953 | btree_node_t *node; |
937 | 954 | ||
938 | hlp = head.next; |
955 | hlp = head.next; |
939 | ASSERT(hlp != &head); |
956 | ASSERT(hlp != &head); |
940 | node = list_get_instance(hlp, btree_node_t, bfs_link); |
957 | node = list_get_instance(hlp, btree_node_t, bfs_link); |
941 | list_remove(hlp); |
958 | list_remove(hlp); |
942 | 959 | ||
943 | ASSERT(node); |
960 | ASSERT(node); |
944 | 961 | ||
945 | if (node->depth != depth) { |
962 | if (node->depth != depth) { |
946 | printf("\n"); |
963 | printf("\n"); |
947 | depth = node->depth; |
964 | depth = node->depth; |
948 | } |
965 | } |
949 | 966 | ||
950 | printf("("); |
967 | printf("("); |
951 | for (i = 0; i < node->keys; i++) { |
968 | for (i = 0; i < node->keys; i++) { |
952 | printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : ""); |
969 | printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : ""); |
953 | if (node->depth && node->subtree[i]) { |
970 | if (node->depth && node->subtree[i]) { |
954 | list_append(&node->subtree[i]->bfs_link, &head); |
971 | list_append(&node->subtree[i]->bfs_link, &head); |
955 | } |
972 | } |
956 | } |
973 | } |
957 | if (node->depth && node->subtree[i]) { |
974 | if (node->depth && node->subtree[i]) { |
958 | list_append(&node->subtree[i]->bfs_link, &head); |
975 | list_append(&node->subtree[i]->bfs_link, &head); |
959 | } |
976 | } |
960 | printf(")"); |
977 | printf(")"); |
961 | } |
978 | } |
962 | printf("\n"); |
979 | printf("\n"); |
963 | 980 | ||
964 | printf("Printing list of leaves:\n"); |
981 | printf("Printing list of leaves:\n"); |
965 | for (cur = t->leaf_head.next; cur != &t->leaf_head; cur = cur->next) { |
982 | for (cur = t->leaf_head.next; cur != &t->leaf_head; cur = cur->next) { |
966 | btree_node_t *node; |
983 | btree_node_t *node; |
967 | 984 | ||
968 | node = list_get_instance(cur, btree_node_t, leaf_link); |
985 | node = list_get_instance(cur, btree_node_t, leaf_link); |
969 | 986 | ||
970 | ASSERT(node); |
987 | ASSERT(node); |
971 | 988 | ||
972 | printf("("); |
989 | printf("("); |
973 | for (i = 0; i < node->keys; i++) |
990 | for (i = 0; i < node->keys; i++) |
974 | printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : ""); |
991 | printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : ""); |
975 | printf(")"); |
992 | printf(")"); |
976 | } |
993 | } |
977 | printf("\n"); |
994 | printf("\n"); |
978 | } |
995 | } |
979 | 996 |