| /* |
| * 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.volley.toolbox; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| |
| /** |
| * A variation of {@link java.io.ByteArrayOutputStream} that uses a pool of byte[] buffers instead |
| * of always allocating them fresh, saving on heap churn. |
| */ |
| public class PoolingByteArrayOutputStream extends ByteArrayOutputStream { |
| /** |
| * If the {@link #PoolingByteArrayOutputStream(ByteArrayPool)} constructor is called, this is |
| * the default size to which the underlying byte array is initialized. |
| */ |
| private static final int DEFAULT_SIZE = 256; |
| |
| private final ByteArrayPool mPool; |
| |
| /** |
| * Constructs a new PoolingByteArrayOutputStream with a default size. If more bytes are written |
| * to this instance, the underlying byte array will expand. |
| */ |
| public PoolingByteArrayOutputStream(ByteArrayPool pool) { |
| this(pool, DEFAULT_SIZE); |
| } |
| |
| /** |
| * Constructs a new {@code ByteArrayOutputStream} with a default size of {@code size} bytes. If |
| * more than {@code size} bytes are written to this instance, the underlying byte array will |
| * expand. |
| * |
| * @param size initial size for the underlying byte array. The value will be pinned to a default |
| * minimum size. |
| */ |
| public PoolingByteArrayOutputStream(ByteArrayPool pool, int size) { |
| mPool = pool; |
| buf = mPool.getBuf(Math.max(size, DEFAULT_SIZE)); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| mPool.returnBuf(buf); |
| buf = null; |
| super.close(); |
| } |
| |
| @Override |
| public void finalize() { |
| mPool.returnBuf(buf); |
| } |
| |
| /** |
| * Ensures there is enough space in the buffer for the given number of additional bytes. |
| */ |
| private void expand(int i) { |
| /* Can the buffer handle @i more bytes, if not expand it */ |
| if (count + i <= buf.length) { |
| return; |
| } |
| byte[] newbuf = mPool.getBuf((count + i) * 2); |
| System.arraycopy(buf, 0, newbuf, 0, count); |
| mPool.returnBuf(buf); |
| buf = newbuf; |
| } |
| |
| @Override |
| public synchronized void write(byte[] buffer, int offset, int len) { |
| expand(len); |
| super.write(buffer, offset, len); |
| } |
| |
| @Override |
| public synchronized void write(int oneByte) { |
| expand(1); |
| super.write(oneByte); |
| } |
| } |