buffer: convert to stdatomic
[ffmpeg.git] / libavutil / tree.c
index 6126ffa..a65d728 100644 (file)
@@ -1,41 +1,49 @@
 /*
  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
  *
- * This file is part of FFmpeg.
+ * This file is part of Libav.
  *
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
  *
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; 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 "error.h"
+#include "mem.h"
 #include "tree.h"
 
-typedef struct AVTreeNode{
+typedef struct AVTreeNode {
     struct AVTreeNode *child[2];
     void *elem;
     int state;
-}AVTreeNode;
+} 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{
-            if(next){
+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);
             }
@@ -45,111 +53,113 @@ void *av_tree_find(const AVTreeNode *t, void *key, int (*cmp)(void *key, const v
     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;
+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;
 
-                            i= (*tp)->state > 0;
-                            (*tp)->child[i  ]->state= 0;
-                            (*tp)->child[i^1]->state= -(*tp)->state;
-                        }
-                        (*tp)->state=0;
+                        (*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;
                     }
-                    return key;
                 }
             }
-            return ret;
-        }else{
-            return t->elem;
+            if (!(*tp)->state ^ !!*next)
+                return key;
         }
-    }else{
-        *tp= av_mallocz(sizeof(AVTreeNode));
-        (*tp)->elem= key;
-        return NULL;
+        return ret;
+    } else {
+        *tp   = *next;
+        *next = NULL;
+        if (*tp) {
+            (*tp)->elem = key;
+            return NULL;
+        } else
+            return key;
     }
 }
 
-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)){
-    int v= f(opaque, t->elem);
-    if(v>=0) av_tree_enumerate(t->child[0], opaque, f);
-    if(v<=0) 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;
+void av_tree_destroy(AVTreeNode *t)
+{
+    if (t) {
+        av_tree_destroy(t->child[0]);
+        av_tree_destroy(t->child[1]);
+        av_free(t);
     }
-    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(void){
-    int i,j,k;
-    AVTreeNode *root= NULL;
-
-    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);
+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);
     }
-    return 0;
 }
-#endif