AVL tree

Originally committed as revision 7031 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 151 insertions, 0 deletions

diff --git a/libavutil/tree.c b/libavutil/tree.c
new file mode 100644
index 0000000000..aff749e791
--- /dev/null
+++ b/libavutil/tree.c
@@ -0,0 +1,151 @@
+/*
+ * 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 "common.h"
+#include "log.h"
+#include "tree.h"
+
+typedef struct AVTreeNode{
+    struct AVTreeNode *child[2];
+    void *elem;
+    int state;
+}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(t->elem, key);
+        if(v){
+            if(next) next[(v>>31)^1]= t->elem;
+            return av_tree_find(t->child[v>>31], key, cmp, next);
+        }else{
+            return t->elem;
+        }
+    }
+    return NULL;
+}
+
+void *av_tree_insert(AVTreeNode **tp, void *key, int (*cmp)(void *key, const void *b)){
+    AVTreeNode *t= *tp;
+    if(t){
+        unsigned int v= cmp(t->elem, key);
+        if(v){
+            int i= v>>31;
+            AVTreeNode **child= &t->child[i];
+            void *ret= av_tree_insert(child, key, cmp);
+            if(!ret){
+                t->state -= ((int)v>>31)|1;
+                if(!(t->state&1)){
+                    if(t->state){
+                        if((*child)->state*2 == t->state){
+                            *tp= *child;
+                            *child= (*child)->child[i^1];
+                            (*tp)->child[i^1]= t;
+                            t->state= 0;
+                        }else{
+                            *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;
+
+                            i= (*tp)->state > 0;
+                            (*tp)->child[i  ]->state= 0;
+                            (*tp)->child[i^1]->state= -(*tp)->state;
+                        }
+                        (*tp)->state=0;
+                    }
+                    return key;
+                }
+            }
+            return ret;
+        }else{
+            return t->elem;
+        }
+    }else{
+        *tp= av_mallocz(sizeof(AVTreeNode));
+        (*tp)->elem= key;
+        return NULL;
+    }
+}
+
+void av_tree_destroy(AVTreeNode *t){
+    av_tree_destroy(t->child[0]);
+    av_tree_destroy(t->child[1]);
+    av_free(t);
+}
+
+#if 0
+void av_tree_enumerate(AVTreeNode *t, void *opaque, int (*f)(void *opaque, void *elem)){
+    f(opaque, t->elem);
+    av_tree_enumerate(t->child[0], opaque, f);
+    av_tree_enumerate(t->child[1], opaque, f);
+}
+#endif
+
+#ifdef TEST
+
+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 %4d\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");
+}
+
+int cmp(const void *a, const void *b){
+    return a-b;
+}
+
+int main(){
+    int i,j,k;
+    AVTreeNode *root= av_mallocz(sizeof(AVTreeNode));
+
+    for(i=0; i<10000; i++){
+        int j= (random()%863294);
+        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);
+        av_tree_insert(&root, (void*)(j+1), cmp);
+    }
+    return 0;
+}
+#endif