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- /*
- * 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
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