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      1 /*
      2  * Copyright (c) 2009-2010 jMonkeyEngine
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are
      7  * met:
      8  *
      9  * * Redistributions of source code must retain the above copyright
     10  *   notice, this list of conditions and the following disclaimer.
     11  *
     12  * * Redistributions in binary form must reproduce the above copyright
     13  *   notice, this list of conditions and the following disclaimer in the
     14  *   documentation and/or other materials provided with the distribution.
     15  *
     16  * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
     17  *   may be used to endorse or promote products derived from this software
     18  *   without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
     24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 package com.jme3.renderer;
     34 
     35 import java.util.Arrays;
     36 
     37 /**
     38  * A specialized data-structure used to optimize state changes of "slot"
     39  * based state.
     40  */
     41 public class IDList {
     42 
     43     public int[] newList = new int[16];
     44     public int[] oldList = new int[16];
     45     public int newLen = 0;
     46     public int oldLen = 0;
     47 
     48     /**
     49      * Reset all states to zero
     50      */
     51     public void reset(){
     52         newLen = 0;
     53         oldLen = 0;
     54         Arrays.fill(newList, 0);
     55         Arrays.fill(oldList, 0);
     56     }
     57 
     58     /**
     59      * Adds an index to the new list.
     60      * If the index was not in the old list, false is returned,
     61      * if the index was in the old list, it is removed from the old
     62      * list and true is returned.
     63      *
     64      * @param idx The index to move
     65      * @return True if it existed in old list and was removed
     66      * from there, false otherwise.
     67      */
     68     public boolean moveToNew(int idx){
     69         if (newLen == 0 || newList[newLen-1] != idx)
     70             // add item to newList first
     71             newList[newLen++] = idx;
     72 
     73         // find idx in oldList, if removed successfuly, return true.
     74         for (int i = 0; i < oldLen; i++){
     75             if (oldList[i] == idx){
     76                 // found index in slot i
     77                 // delete index from old list
     78                 oldLen --;
     79                 for (int j = i; j < oldLen; j++){
     80                     oldList[j] = oldList[j+1];
     81                 }
     82                 return true;
     83             }
     84         }
     85         return false;
     86     }
     87 
     88     /**
     89      * Copies the new list to the old list, and clears the new list.
     90      */
     91     public void copyNewToOld(){
     92         System.arraycopy(newList, 0, oldList, 0, newLen);
     93         oldLen = newLen;
     94         newLen = 0;
     95     }
     96 
     97     /**
     98      * Prints the contents of the lists
     99      */
    100     public void print(){
    101         if (newLen > 0){
    102             System.out.print("New List: ");
    103             for (int i = 0; i < newLen; i++){
    104                 if (i == newLen -1)
    105                     System.out.println(newList[i]);
    106                 else
    107                     System.out.print(newList[i]+", ");
    108             }
    109         }
    110         if (oldLen > 0){
    111             System.out.print("Old List: ");
    112             for (int i = 0; i < oldLen; i++){
    113                 if (i == oldLen -1)
    114                     System.out.println(oldList[i]);
    115                 else
    116                     System.out.print(oldList[i]+", ");
    117             }
    118         }
    119     }
    120 
    121 }
    122