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