| /* |
| * 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 |