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
17package com.android.tv.settings.util;
18
19import java.util.ArrayList;
20import java.util.List;
21
22public 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