067e5b096e799a7bf3cc3d20240d02d83fd2ccf8
[libav.git] / libavutil / tree.c
1 /*
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of Libav.
5 *
6 * Libav is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * Libav is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "log.h"
22 #include "tree.h"
23
24 typedef struct AVTreeNode{
25 struct AVTreeNode *child[2];
26 void *elem;
27 int state;
28 }AVTreeNode;
29
30 const int av_tree_node_size = sizeof(AVTreeNode);
31
32 void *av_tree_find(const AVTreeNode *t, void *key, int (*cmp)(void *key, const void *b), void *next[2]){
33 if(t){
34 unsigned int v= cmp(key, t->elem);
35 if(v){
36 if(next) next[v>>31]= t->elem;
37 return av_tree_find(t->child[(v>>31)^1], key, cmp, next);
38 }else{
39 if(next){
40 av_tree_find(t->child[0], key, cmp, next);
41 av_tree_find(t->child[1], key, cmp, next);
42 }
43 return t->elem;
44 }
45 }
46 return NULL;
47 }
48
49 void *av_tree_insert(AVTreeNode **tp, void *key, int (*cmp)(void *key, const void *b), AVTreeNode **next){
50 AVTreeNode *t= *tp;
51 if(t){
52 unsigned int v= cmp(t->elem, key);
53 void *ret;
54 if(!v){
55 if(*next)
56 return t->elem;
57 else if(t->child[0]||t->child[1]){
58 int i= !t->child[0];
59 void *next_elem[2];
60 av_tree_find(t->child[i], key, cmp, next_elem);
61 key= t->elem= next_elem[i];
62 v= -i;
63 }else{
64 *next= t;
65 *tp=NULL;
66 return NULL;
67 }
68 }
69 ret= av_tree_insert(&t->child[v>>31], key, cmp, next);
70 if(!ret){
71 int i= (v>>31) ^ !!*next;
72 AVTreeNode **child= &t->child[i];
73 t->state += 2*i - 1;
74
75 if(!(t->state&1)){
76 if(t->state){
77 /* The following code is equivalent to
78 if((*child)->state*2 == -t->state)
79 rotate(child, i^1);
80 rotate(tp, i);
81
82 with rotate():
83 static void rotate(AVTreeNode **tp, int i){
84 AVTreeNode *t= *tp;
85
86 *tp= t->child[i];
87 t->child[i]= t->child[i]->child[i^1];
88 (*tp)->child[i^1]= t;
89 i= 4*t->state + 2*(*tp)->state + 12;
90 t ->state= ((0x614586 >> i) & 3)-1;
91 (*tp)->state= ((*tp)->state>>1) + ((0x400EEA >> i) & 3)-1;
92 }
93 but such a rotate function is both bigger and slower
94 */
95 if((*child)->state*2 == -t->state){
96 *tp= (*child)->child[i^1];
97 (*child)->child[i^1]= (*tp)->child[i];
98 (*tp)->child[i]= *child;
99 *child= (*tp)->child[i^1];
100 (*tp)->child[i^1]= t;
101
102 (*tp)->child[0]->state= -((*tp)->state>0);
103 (*tp)->child[1]->state= (*tp)->state<0 ;
104 (*tp)->state=0;
105 }else{
106 *tp= *child;
107 *child= (*child)->child[i^1];
108 (*tp)->child[i^1]= t;
109 if((*tp)->state) t->state = 0;
110 else t->state>>= 1;
111 (*tp)->state= -t->state;
112 }
113 }
114 }
115 if(!(*tp)->state ^ !!*next)
116 return key;
117 }
118 return ret;
119 }else{
120 *tp= *next; *next= NULL;
121 if(*tp){
122 (*tp)->elem= key;
123 return NULL;
124 }else
125 return key;
126 }
127 }
128
129 void av_tree_destroy(AVTreeNode *t){
130 if(t){
131 av_tree_destroy(t->child[0]);
132 av_tree_destroy(t->child[1]);
133 av_free(t);
134 }
135 }
136
137 void av_tree_enumerate(AVTreeNode *t, void *opaque, int (*cmp)(void *opaque, void *elem), int (*enu)(void *opaque, void *elem)){
138 if(t){
139 int v= cmp ? cmp(opaque, t->elem) : 0;
140 if(v>=0) av_tree_enumerate(t->child[0], opaque, cmp, enu);
141 if(v==0) enu(opaque, t->elem);
142 if(v<=0) av_tree_enumerate(t->child[1], opaque, cmp, enu);
143 }
144 }
145
146 #ifdef TEST
147
148 #include "lfg.h"
149
150 static int check(AVTreeNode *t){
151 if(t){
152 int left= check(t->child[0]);
153 int right= check(t->child[1]);
154
155 if(left>999 || right>999)
156 return 1000;
157 if(right - left != t->state)
158 return 1000;
159 if(t->state>1 || t->state<-1)
160 return 1000;
161 return FFMAX(left, right)+1;
162 }
163 return 0;
164 }
165
166 static void print(AVTreeNode *t, int depth){
167 int i;
168 for(i=0; i<depth*4; i++) av_log(NULL, AV_LOG_ERROR, " ");
169 if(t){
170 av_log(NULL, AV_LOG_ERROR, "Node %p %2d %p\n", t, t->state, t->elem);
171 print(t->child[0], depth+1);
172 print(t->child[1], depth+1);
173 }else
174 av_log(NULL, AV_LOG_ERROR, "NULL\n");
175 }
176
177 static int cmp(void *a, const void *b){
178 return (uint8_t*)a-(const uint8_t*)b;
179 }
180
181 int main(void){
182 int i;
183 void *k;
184 AVTreeNode *root= NULL, *node=NULL;
185 AVLFG prng;
186
187 av_lfg_init(&prng, 1);
188
189 for(i=0; i<10000; i++){
190 int j = av_lfg_get(&prng) % 86294;
191 if(check(root) > 999){
192 av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i);
193 print(root, 0);
194 return -1;
195 }
196 av_log(NULL, AV_LOG_ERROR, "inserting %4d\n", j);
197 if(!node)
198 node= av_mallocz(av_tree_node_size);
199 av_tree_insert(&root, (void*)(j+1), cmp, &node);
200
201 j = av_lfg_get(&prng) % 86294;
202 {
203 AVTreeNode *node2=NULL;
204 av_log(NULL, AV_LOG_ERROR, "removing %4d\n", j);
205 av_tree_insert(&root, (void*)(j+1), cmp, &node2);
206 k= av_tree_find(root, (void*)(j+1), cmp, NULL);
207 if(k)
208 av_log(NULL, AV_LOG_ERROR, "removal failure %d\n", i);
209 }
210 }
211 return 0;
212 }
213 #endif