/* * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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; #if FF_API_CONTEXT_SIZE const int av_tree_node_size = sizeof(AVTreeNode); #endif struct AVTreeNode *av_tree_node_alloc(void) { return av_mallocz(sizeof(struct 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 = ((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); } } #ifdef TEST #include "common.h" #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; AVTreeNode *root = NULL, *node = NULL; AVLFG prng; av_lfg_init(&prng, 1); for (i = 0; i < 10000; i++) { AVTreeNode *node2 = NULL; intptr_t j = av_lfg_get(&prng) % 86294; void *ret, *jj = (void *)(j + 1); while (ret = av_tree_find(root, jj, cmp, NULL)) { j = av_lfg_get(&prng) % 86294; jj = (void *)(j + 1); } if (check(root) > 999) { av_log(NULL, AV_LOG_ERROR, "FATAL error %d\n", i); print(root, 0); return 1; } if (!node) node = av_tree_node_alloc(); if (!node) { av_log(NULL, AV_LOG_ERROR, "Memory allocation failure.\n"); return 1; } av_tree_insert(&root, jj, cmp, &node); while (ret = av_tree_find(root, jj, cmp, NULL)) { j = av_lfg_get(&prng) % 86294; jj = (void *)(j + 1); } ret = av_tree_insert(&root, jj, cmp, &node2); if (ret != jj) av_tree_destroy(node2); ret = av_tree_find(root, jj, cmp, NULL); if (ret) av_log(NULL, AV_LOG_ERROR, "removal failure %d\n", i); } av_tree_destroy(root); return 0; } #endif