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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.gallery3d.data;
import com.android.gallery3d.util.ThreadPool.JobContext;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
public class BytesBufferPool {
private static final int READ_STEP = 4096;
public static class BytesBuffer {
public byte[] data;
public int offset;
public int length;
private BytesBuffer(int capacity) {
this.data = new byte[capacity];
}
// an helper function to read content from FileDescriptor
public void readFrom(JobContext jc, FileDescriptor fd) throws IOException {
FileInputStream fis = new FileInputStream(fd);
length = 0;
try {
int capacity = data.length;
while (true) {
int step = Math.min(READ_STEP, capacity - length);
int rc = fis.read(data, length, step);
if (rc < 0 || jc.isCancelled()) return;
length += rc;
if (length == capacity) {
byte[] newData = new byte[data.length * 2];
System.arraycopy(data, 0, newData, 0, data.length);
data = newData;
capacity = data.length;
}
}
} finally {
fis.close();
}
}
}
private final int mPoolSize;
private final int mBufferSize;
private final ArrayList<BytesBuffer> mList;
public BytesBufferPool(int poolSize, int bufferSize) {
mList = new ArrayList<BytesBuffer>(poolSize);
mPoolSize = poolSize;
mBufferSize = bufferSize;
}
public synchronized BytesBuffer get() {
int n = mList.size();
return n > 0 ? mList.remove(n - 1) : new BytesBuffer(mBufferSize);
}
public synchronized void recycle(BytesBuffer buffer) {
if (buffer.data.length != mBufferSize) return;
if (mList.size() < mPoolSize) {
buffer.offset = 0;
buffer.length = 0;
mList.add(buffer);
}
}
public synchronized void clear() {
mList.clear();
}
}
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