yading@11: /*
yading@11:  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "log.h"
yading@11: #include "mem.h"
yading@11: #include "tree.h"
yading@11: 
yading@11: typedef struct AVTreeNode {
yading@11:     struct AVTreeNode *child[2];
yading@11:     void *elem;
yading@11:     int state;
yading@11: } AVTreeNode;
yading@11: 
yading@11: const int av_tree_node_size = sizeof(AVTreeNode);
yading@11: 
yading@11: struct AVTreeNode *av_tree_node_alloc(void)
yading@11: {
yading@11:     return av_mallocz(sizeof(struct AVTreeNode));
yading@11: }
yading@11: 
yading@11: void *av_tree_find(const AVTreeNode *t, void *key,
yading@11:                    int (*cmp)(void *key, const void *b), void *next[2])
yading@11: {
yading@11:     if (t) {
yading@11:         unsigned int v = cmp(key, t->elem);
yading@11:         if (v) {
yading@11:             if (next) next[v >> 31] = t->elem;
yading@11:             return av_tree_find(t->child[(v >> 31) ^ 1], key, cmp, next);
yading@11:         } else {
yading@11:             if (next) {
yading@11:                 av_tree_find(t->child[0], key, cmp, next);
yading@11:                 av_tree_find(t->child[1], key, cmp, next);
yading@11:             }
yading@11:             return t->elem;
yading@11:         }
yading@11:     }
yading@11:     return NULL;
yading@11: }
yading@11: 
yading@11: void *av_tree_insert(AVTreeNode **tp, void *key,
yading@11:                      int (*cmp)(void *key, const void *b), AVTreeNode **next)
yading@11: {
yading@11:     AVTreeNode *t = *tp;
yading@11:     if (t) {
yading@11:         unsigned int v = cmp(t->elem, key);
yading@11:         void *ret;
yading@11:         if (!v) {
yading@11:             if (*next)
yading@11:                 return t->elem;
yading@11:             else if (t->child[0] || t->child[1]) {
yading@11:                 int i = !t->child[0];
yading@11:                 void *next_elem[2];
yading@11:                 av_tree_find(t->child[i], key, cmp, next_elem);
yading@11:                 key = t->elem = next_elem[i];
yading@11:                 v = -i;
yading@11:             } else {
yading@11:                 *next = t;
yading@11:                 *tp = NULL;
yading@11:                 return NULL;
yading@11:             }
yading@11:         }
yading@11:         ret = av_tree_insert(&t->child[v >> 31], key, cmp, next);
yading@11:         if (!ret) {
yading@11:             int i = (v >> 31) ^ !!*next;
yading@11:             AVTreeNode **child = &t->child[i];
yading@11:             t->state += 2 * i - 1;
yading@11: 
yading@11:             if (!(t->state & 1)) {
yading@11:                 if (t->state) {
yading@11:                     /* The following code is equivalent to
yading@11:                     if((*child)->state*2 == -t->state)
yading@11:                         rotate(child, i^1);
yading@11:                     rotate(tp, i);
yading@11: 
yading@11:                     with rotate():
yading@11:                     static void rotate(AVTreeNode **tp, int i) {
yading@11:                         AVTreeNode *t= *tp;
yading@11: 
yading@11:                         *tp= t->child[i];
yading@11:                         t->child[i]= t->child[i]->child[i^1];
yading@11:                         (*tp)->child[i^1]= t;
yading@11:                         i= 4*t->state + 2*(*tp)->state + 12;
yading@11:                           t  ->state=                     ((0x614586 >> i) & 3)-1;
yading@11:                         (*tp)->state= ((*tp)->state>>1) + ((0x400EEA >> i) & 3)-1;
yading@11:                     }
yading@11:                     but such a rotate function is both bigger and slower
yading@11:                     */
yading@11:                     if (( *child )->state * 2 == -t->state) {
yading@11:                         *tp                    = (*child)->child[i ^ 1];
yading@11:                         (*child)->child[i ^ 1] = (*tp)->child[i];
yading@11:                         (*tp)->child[i]        = *child;
yading@11:                         *child                 = ( *tp )->child[i ^ 1];
yading@11:                         (*tp)->child[i ^ 1]    = t;
yading@11: 
yading@11:                         (*tp)->child[0]->state = -((*tp)->state > 0);
yading@11:                         (*tp)->child[1]->state =   (*tp)->state < 0;
yading@11:                         (*tp)->state           = 0;
yading@11:                     } else {
yading@11:                         *tp                    = *child;
yading@11:                         *child                 = (*child)->child[i ^ 1];
yading@11:                         (*tp)->child[i ^ 1]    = t;
yading@11:                         if ((*tp)->state) t->state = 0;
yading@11:                         else              t->state >>= 1;
yading@11:                         (*tp)->state           = -t->state;
yading@11:                     }
yading@11:                 }
yading@11:             }
yading@11:             if (!(*tp)->state ^ !!*next)
yading@11:                 return key;
yading@11:         }
yading@11:         return ret;
yading@11:     } else {
yading@11:         *tp   = *next;
yading@11:         *next = NULL;
yading@11:         if (*tp) {
yading@11:             (*tp)->elem = key;
yading@11:             return NULL;
yading@11:         } else
yading@11:             return key;
yading@11:     }
yading@11: }
yading@11: 
yading@11: void av_tree_destroy(AVTreeNode *t)
yading@11: {
yading@11:     if (t) {
yading@11:         av_tree_destroy(t->child[0]);
yading@11:         av_tree_destroy(t->child[1]);
yading@11:         av_free(t);
yading@11:     }
yading@11: }
yading@11: 
yading@11: void av_tree_enumerate(AVTreeNode *t, void *opaque,
yading@11:                        int (*cmp)(void *opaque, void *elem),
yading@11:                        int (*enu)(void *opaque, void *elem))
yading@11: {
yading@11:     if (t) {
yading@11:         int v = cmp ? cmp(opaque, t->elem) : 0;
yading@11:         if (v >= 0)
yading@11:             av_tree_enumerate(t->child[0], opaque, cmp, enu);
yading@11:         if (v == 0)
yading@11:             enu(opaque, t->elem);
yading@11:         if (v <= 0)
yading@11:             av_tree_enumerate(t->child[1], opaque, cmp, enu);
yading@11:     }
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: 
yading@11: #include "common.h"
yading@11: #include "lfg.h"
yading@11: 
yading@11: static int check(AVTreeNode *t)
yading@11: {
yading@11:     if (t) {
yading@11:         int left  = check(t->child[0]);
yading@11:         int right = check(t->child[1]);
yading@11: 
yading@11:         if (left>999 || right>999)
yading@11:             return 1000;
yading@11:         if (right - left != t->state)
yading@11:             return 1000;
yading@11:         if (t->state>1 || t->state<-1)
yading@11:             return 1000;
yading@11:         return FFMAX(left, right) + 1;
yading@11:     }
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static void print(AVTreeNode *t, int depth)
yading@11: {
yading@11:     int i;
yading@11:     for (i = 0; i < depth * 4; i++) av_log(NULL, AV_LOG_ERROR, " ");
yading@11:     if (t) {
yading@11:         av_log(NULL, AV_LOG_ERROR, "Node %p %2d %p\n", t, t->state, t->elem);
yading@11:         print(t->child[0], depth + 1);
yading@11:         print(t->child[1], depth + 1);
yading@11:     } else
yading@11:         av_log(NULL, AV_LOG_ERROR, "NULL\n");
yading@11: }
yading@11: 
yading@11: static int cmp(void *a, const void *b)
yading@11: {
yading@11:     return (uint8_t *) a - (const uint8_t *) b;
yading@11: }
yading@11: 
yading@11: int main (void)
yading@11: {
yading@11:     int i;
yading@11:     void *k;
yading@11:     AVTreeNode *root = NULL, *node = NULL;
yading@11:     AVLFG prng;
yading@11: 
yading@11:     av_lfg_init(&prng, 1);
yading@11: 
yading@11:     for (i = 0; i < 10000; i++) {
yading@11:         intptr_t j = av_lfg_get(&prng) % 86294;
yading@11:         if (check(root) > 999) {
yading@11:             av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i);
yading@11:         print(root, 0);
yading@11:             return -1;
yading@11:         }
yading@11:         av_log(NULL, AV_LOG_ERROR, "inserting %4d\n", (int)j);
yading@11:         if (!node)
yading@11:             node = av_tree_node_alloc();
yading@11:         av_tree_insert(&root, (void *) (j + 1), cmp, &node);
yading@11: 
yading@11:         j = av_lfg_get(&prng) % 86294;
yading@11:         {
yading@11:             AVTreeNode *node2 = NULL;
yading@11:             av_log(NULL, AV_LOG_ERROR, "removing %4d\n", (int)j);
yading@11:             av_tree_insert(&root, (void *) (j + 1), cmp, &node2);
yading@11:             k = av_tree_find(root, (void *) (j + 1), cmp, NULL);
yading@11:             if (k)
yading@11:                 av_log(NULL, AV_LOG_ERROR, "removal failure %d\n", i);
yading@11:         }
yading@11:     }
yading@11:     return 0;
yading@11: }
yading@11: #endif