/* * 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 "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); } } void av_tree_enumerate(AVTreeNode *t, void *opaque, int (*cmp)(void *opaque, void *elem), int (*enu)(void *opaque, void *elem)){ if(t){ int v= cmp ? cmp(opaque, t->elem) : 0; if(v>=0) av_tree_enumerate(t->child[0], opaque, cmp, enu); if(v==0) enu(opaque, t->elem); if(v<=0) av_tree_enumerate(t->child[1], opaque, cmp, enu); } } #ifdef TEST #include "lfg.h" 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 %p\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"); } static int cmp(void *a, const void *b){ return (uint8_t*)a-(const uint8_t*)b; } int main(void){ int i; void *k; AVTreeNode *root= NULL, *node=NULL; AVLFG prng; av_lfg_init(&prng, 1); for(i=0; i<10000; i++){ int j = av_lfg_get(&prng) % 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 = av_lfg_get(&prng) % 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