Replace FFmpeg with Libav in licence headers
[ffmpeg.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