[FFmpeg-cvslog] r11603 - trunk/libavutil/tree.c
michael
subversion
Wed Jan 23 22:03:21 CET 2008
Author: michael
Date: Wed Jan 23 22:03:21 2008
New Revision: 11603
Log:
Comment to explain how the add/remove core works.
Modified:
trunk/libavutil/tree.c
Modified: trunk/libavutil/tree.c
==============================================================================
--- trunk/libavutil/tree.c (original)
+++ trunk/libavutil/tree.c Wed Jan 23 22:03:21 2008
@@ -75,6 +75,24 @@ void *av_tree_insert(AVTreeNode **tp, vo
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];
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