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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.tv.settings.util;
     18 
     19 import java.util.ArrayList;
     20 import java.util.List;
     21 
     22 public final class ByteArrayPool {
     23 
     24     public static final int CHUNK16K = 16 * 1024;
     25     public static final int DEFAULT_MAX_NUM = 8;
     26 
     27     private final static ByteArrayPool sChunk16K = new ByteArrayPool(CHUNK16K, DEFAULT_MAX_NUM);
     28 
     29     private final ArrayList<byte[]> mCachedBuf;
     30     private final int mChunkSize;
     31     private final int mMaxNum;
     32 
     33     private ByteArrayPool(int chunkSize, int maxNum) {
     34         mChunkSize = chunkSize;
     35         mMaxNum = maxNum;
     36         mCachedBuf = new ArrayList<byte[]>(mMaxNum);
     37     }
     38 
     39     /**
     40      * get singleton of 16KB byte[] pool
     41      */
     42     public static ByteArrayPool get16KBPool() {
     43         return sChunk16K;
     44     }
     45 
     46     public byte[] allocateChunk() {
     47         synchronized (mCachedBuf) {
     48             int size = mCachedBuf.size();
     49             if (size > 0) {
     50                 return mCachedBuf.remove(size - 1);
     51             }
     52             return new byte[mChunkSize];
     53         }
     54     }
     55 
     56     public void clear() {
     57         synchronized (mCachedBuf) {
     58             mCachedBuf.clear();
     59         }
     60     }
     61 
     62     public void releaseChunk(byte[] buf) {
     63         if (buf == null || buf.length != mChunkSize) {
     64             return;
     65         }
     66         synchronized (mCachedBuf) {
     67             if (mCachedBuf.size() < mMaxNum) {
     68                 mCachedBuf.add(buf);
     69             }
     70         }
     71     }
     72 
     73     public void releaseChunks(List<byte[]> bufs) {
     74         synchronized (mCachedBuf) {
     75             for (int i = 0, c = bufs.size(); i < c; i++) {
     76                 if (mCachedBuf.size() == mMaxNum) {
     77                     break;
     78                 }
     79                 byte[] buf = bufs.get(i);
     80                 if (buf != null && buf.length == mChunkSize) {
     81                     mCachedBuf.add(bufs.get(i));
     82                 }
     83             }
     84         }
     85     }
     86 
     87 }
     88