Flip key and element so types match, not that it matters for any code
[ffmpeg.git] / libavutil / tree.c
1 /*
2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20
21 #include "common.h"
22 #include "log.h"
23 #include "tree.h"
24
25 typedef struct AVTreeNode{
26     struct AVTreeNode *child[2];
27     void *elem;
28     int state;
29 }AVTreeNode;
30
31 const int av_tree_node_size = sizeof(AVTreeNode);
32
33 void *av_tree_find(const AVTreeNode *t, void *key, int (*cmp)(void *key, const void *b), void *next[2]){
34     if(t){
35         unsigned int v= cmp(key, t->elem);
36         if(v){
37             if(next) next[v>>31]= t->elem;
38             return av_tree_find(t->child[(v>>31)^1], key, cmp, next);
39         }else{
40             if(next){
41                 av_tree_find(t->child[0], key, cmp, next);
42                 av_tree_find(t->child[1], key, cmp, next);
43             }
44             return t->elem;
45         }
46     }
47     return NULL;
48 }
49
50 void *av_tree_insert(AVTreeNode **tp, void *key, int (*cmp)(void *key, const void *b), AVTreeNode **next){
51     AVTreeNode *t= *tp;
52     if(t){
53         unsigned int v= cmp(t->elem, key);
54         void *ret;
55         if(!v){
56             if(*next)
57                 return t->elem;
58             else if(t->child[0]||t->child[1]){
59                 int i= !t->child[0];
60                 AVTreeNode **child= &t->child[i];
61                 void *next_elem[2];
62                 av_tree_find(*child, key, cmp, next_elem);
63                 key= t->elem= next_elem[i];
64                 v= -i;
65             }else{
66                 *next= t;
67                 *tp=NULL;
68                 return NULL;
69             }
70         }
71             ret= av_tree_insert(&t->child[v>>31], key, cmp, next);
72             if(!ret){
73                 int i= (v>>31) ^ !!*next;
74                 AVTreeNode **child= &t->child[i];
75                 t->state += 2*i - 1;
76
77                 if(!(t->state&1)){
78                     if(t->state){
79                         if((*child)->state*2 == -t->state){
80                             *tp= (*child)->child[i^1];
81                             (*child)->child[i^1]= (*tp)->child[i];
82                             (*tp)->child[i]= *child;
83                             *child= (*tp)->child[i^1];
84                             (*tp)->child[i^1]= t;
85
86                             (*tp)->child[0]->state= -((*tp)->state>0);
87                             (*tp)->child[1]->state=   (*tp)->state<0 ;
88                             (*tp)->state=0;
89                         }else{
90                             *tp= *child;
91                             *child= (*child)->child[i^1];
92                             (*tp)->child[i^1]= t;
93                             if((*tp)->state) t->state  = 0;
94                             else             t->state>>= 1;
95                             (*tp)->state= -t->state;
96                         }
97                     }
98                 }
99                 if(!(*tp)->state ^ !!*next)
100                     return key;
101             }
102             return ret;
103     }else{
104         *tp= *next; *next= NULL;
105         (*tp)->elem= key;
106         return NULL;
107     }
108 }
109
110 void av_tree_destroy(AVTreeNode *t){
111     av_tree_destroy(t->child[0]);
112     av_tree_destroy(t->child[1]);
113     av_free(t);
114 }
115
116 #if 0
117 void av_tree_enumerate(AVTreeNode *t, void *opaque, int (*f)(void *opaque, void *elem)){
118     int v= f(opaque, t->elem);
119     if(v>=0) av_tree_enumerate(t->child[0], opaque, f);
120     if(v<=0) av_tree_enumerate(t->child[1], opaque, f);
121 }
122 #endif
123
124 #ifdef TEST
125 #undef random
126 static int check(AVTreeNode *t){
127     if(t){
128         int left= check(t->child[0]);
129         int right= check(t->child[1]);
130
131         if(left>999 || right>999)
132             return 1000;
133         if(right - left != t->state)
134             return 1000;
135         if(t->state>1 || t->state<-1)
136             return 1000;
137         return FFMAX(left, right)+1;
138     }
139     return 0;
140 }
141
142 static void print(AVTreeNode *t, int depth){
143     int i;
144     for(i=0; i<depth*4; i++) av_log(NULL, AV_LOG_ERROR, " ");
145     if(t){
146         av_log(NULL, AV_LOG_ERROR, "Node %p %2d %4d\n", t, t->state, t->elem);
147         print(t->child[0], depth+1);
148         print(t->child[1], depth+1);
149     }else
150         av_log(NULL, AV_LOG_ERROR, "NULL\n");
151 }
152
153 int cmp(const void *a, const void *b){
154     return a-b;
155 }
156
157 int main(void){
158     int i,j,k;
159     AVTreeNode *root= NULL, *node=NULL;
160
161     for(i=0; i<10000; i++){
162         int j= (random()%86294);
163         if(check(root) > 999){
164             av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i);
165         print(root, 0);
166             return -1;
167         }
168         av_log(NULL, AV_LOG_ERROR, "inserting %4d\n", j);
169         if(!node)
170             node= av_mallocz(av_tree_node_size);
171         av_tree_insert(&root, (void*)(j+1), cmp, &node);
172
173         j= (random()%86294);
174         k= av_tree_find(root, (void*)(j+1), cmp, NULL);
175         if(k){
176             AVTreeNode *node2=NULL;
177             av_tree_insert(&root, (void*)(j+1), cmp, &node2);
178             k= av_tree_find(root, (void*)(j+1), cmp, NULL);
179             if(k)
180                 av_log(NULL, AV_LOG_ERROR, "removial failure %d\n", i);
181         }
182     }
183     return 0;
184 }
185 #endif