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DEFINITIONS
This source file includes following definitions.
- av_tree_find
- av_tree_insert
- av_tree_destroy
- av_tree_enumerate
- check
- print
- cmp
- main
/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
#include "log.h"
#include "tree.h"
typedef struct AVTreeNode{
struct AVTreeNode *child[2];
void *elem;
int state;
}AVTreeNode;
const int av_tree_node_size = sizeof(AVTreeNode);
void *av_tree_find(const AVTreeNode *t, void *key, int (*cmp)(void *key, const void *b), void *next[2]){
if(t){
unsigned int v= cmp(key, t->elem);
if(v){
if(next) next[v>>31]= t->elem;
return av_tree_find(t->child[(v>>31)^1], key, cmp, next);
}else{
if(next){
av_tree_find(t->child[0], key, cmp, next);
av_tree_find(t->child[1], key, cmp, next);
}
return t->elem;
}
}
return NULL;
}
void *av_tree_insert(AVTreeNode **tp, void *key, int (*cmp)(void *key, const void *b), AVTreeNode **next){
AVTreeNode *t= *tp;
if(t){
unsigned int v= cmp(t->elem, key);
void *ret;
if(!v){
if(*next)
return t->elem;
else if(t->child[0]||t->child[1]){
int i= !t->child[0];
void *next_elem[2];
av_tree_find(t->child[i], key, cmp, next_elem);
key= t->elem= next_elem[i];
v= -i;
}else{
*next= t;
*tp=NULL;
return NULL;
}
}
ret= av_tree_insert(&t->child[v>>31], key, cmp, next);
if(!ret){
int i= (v>>31) ^ !!*next;
AVTreeNode **child= &t->child[i];
t->state += 2*i - 1;
if(!(t->state&1)){
if(t->state){
/* The following code is equivalent to
if((*child)->state*2 == -t->state)
rotate(child, i^1);
rotate(tp, i);
with rotate():
static void rotate(AVTreeNode **tp, int i){
AVTreeNode *t= *tp;
*tp= t->child[i];
t->child[i]= t->child[i]->child[i^1];
(*tp)->child[i^1]= t;
i= 4*t->state + 2*(*tp)->state + 12;
t ->state= ((0x614586 >> i) & 3)-1;
(*tp)->state= ((*tp)->state>>1) + ((0x400EEA >> i) & 3)-1;
}
but such a rotate function is both bigger and slower
*/
if((*child)->state*2 == -t->state){
*tp= (*child)->child[i^1];
(*child)->child[i^1]= (*tp)->child[i];
(*tp)->child[i]= *child;
*child= (*tp)->child[i^1];
(*tp)->child[i^1]= t;
(*tp)->child[0]->state= -((*tp)->state>0);
(*tp)->child[1]->state= (*tp)->state<0 ;
(*tp)->state=0;
}else{
*tp= *child;
*child= (*child)->child[i^1];
(*tp)->child[i^1]= t;
if((*tp)->state) t->state = 0;
else t->state>>= 1;
(*tp)->state= -t->state;
}
}
}
if(!(*tp)->state ^ !!*next)
return key;
}
return ret;
}else{
*tp= *next; *next= NULL;
if(*tp){
(*tp)->elem= key;
return NULL;
}else
return key;
}
}
void av_tree_destroy(AVTreeNode *t){
if(t){
av_tree_destroy(t->child[0]);
av_tree_destroy(t->child[1]);
av_free(t);
}
}
#if 0
void av_tree_enumerate(AVTreeNode *t, void *opaque, int (*f)(void *opaque, void *elem)){
int v= f(opaque, t->elem);
if(v>=0) av_tree_enumerate(t->child[0], opaque, f);
if(v<=0) av_tree_enumerate(t->child[1], opaque, f);
}
#endif
#ifdef TEST
#undef random
static int check(AVTreeNode *t){
if(t){
int left= check(t->child[0]);
int right= check(t->child[1]);
if(left>999 || right>999)
return 1000;
if(right - left != t->state)
return 1000;
if(t->state>1 || t->state<-1)
return 1000;
return FFMAX(left, right)+1;
}
return 0;
}
static void print(AVTreeNode *t, int depth){
int i;
for(i=0; i<depth*4; i++) av_log(NULL, AV_LOG_ERROR, " ");
if(t){
av_log(NULL, AV_LOG_ERROR, "Node %p %2d %4d\n", t, t->state, t->elem);
print(t->child[0], depth+1);
print(t->child[1], depth+1);
}else
av_log(NULL, AV_LOG_ERROR, "NULL\n");
}
int cmp(const void *a, const void *b){
return a-b;
}
int main(void){
int i,k;
AVTreeNode *root= NULL, *node=NULL;
for(i=0; i<10000; i++){
int j= (random()%86294);
if(check(root) > 999){
av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i);
print(root, 0);
return -1;
}
av_log(NULL, AV_LOG_ERROR, "inserting %4d\n", j);
if(!node)
node= av_mallocz(av_tree_node_size);
av_tree_insert(&root, (void*)(j+1), cmp, &node);
j= (random()%86294);
{
AVTreeNode *node2=NULL;
av_log(NULL, AV_LOG_ERROR, "removing %4d\n", j);
av_tree_insert(&root, (void*)(j+1), cmp, &node2);
k= av_tree_find(root, (void*)(j+1), cmp, NULL);
if(k)
av_log(NULL, AV_LOG_ERROR, "removal failure %d\n", i);
}
}
return 0;
}
#endif