/* * 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 "error.h"#include "log.h"#include "mem.h"#include "tree.h" typedef struct AVTreeNode {    struct AVTreeNode *child[2];    void *elem;    int state;} AVTreeNode; const int av_tree_node_size = sizeof(AVTreeNode); struct AVTreeNode *av_tree_node_alloc(void){    return av_mallocz(sizeof(struct AVTreeNode));} void *av_tree_find(const AVTreeNode *t, void *key,                   int (*cmp)(const 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)(const 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 = ((0x400EEA >> i) & 3) - 1 +                     *                    ((*tp)->state >> 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);    }}