| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 |
| * |
| * https://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 org.apache.avro.util; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.nio.Buffer; |
| import java.nio.ByteBuffer; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Utility to collect data written to an {@link OutputStream} in |
| * {@link ByteBuffer}s. |
| */ |
| public class ByteBufferOutputStream extends OutputStream { |
| public static final int BUFFER_SIZE = 8192; |
| |
| private List<ByteBuffer> buffers; |
| |
| public ByteBufferOutputStream() { |
| reset(); |
| } |
| |
| /** Returns all data written and resets the stream to be empty. */ |
| public List<ByteBuffer> getBufferList() { |
| List<ByteBuffer> result = buffers; |
| reset(); |
| for (Buffer buffer : result) { |
| buffer.flip(); |
| } |
| return result; |
| } |
| |
| /** Prepend a list of ByteBuffers to this stream. */ |
| public void prepend(List<ByteBuffer> lists) { |
| for (Buffer buffer : lists) { |
| buffer.position(buffer.limit()); |
| } |
| buffers.addAll(0, lists); |
| } |
| |
| /** Append a list of ByteBuffers to this stream. */ |
| public void append(List<ByteBuffer> lists) { |
| for (Buffer buffer : lists) { |
| buffer.position(buffer.limit()); |
| } |
| buffers.addAll(lists); |
| } |
| |
| public void reset() { |
| buffers = new ArrayList<>(); |
| buffers.add(ByteBuffer.allocate(BUFFER_SIZE)); |
| } |
| |
| public void write(ByteBuffer buffer) { |
| buffers.add(buffer); |
| } |
| |
| @Override |
| public void write(int b) { |
| ByteBuffer buffer = buffers.get(buffers.size() - 1); |
| if (buffer.remaining() < 1) { |
| buffer = ByteBuffer.allocate(BUFFER_SIZE); |
| buffers.add(buffer); |
| } |
| buffer.put((byte) b); |
| } |
| |
| @Override |
| public void write(byte[] b, int off, int len) { |
| ByteBuffer buffer = buffers.get(buffers.size() - 1); |
| int remaining = buffer.remaining(); |
| while (len > remaining) { |
| buffer.put(b, off, remaining); |
| len -= remaining; |
| off += remaining; |
| buffer = ByteBuffer.allocate(BUFFER_SIZE); |
| buffers.add(buffer); |
| remaining = buffer.remaining(); |
| } |
| buffer.put(b, off, len); |
| } |
| |
| /** Add a buffer to the output without copying, if possible. */ |
| public void writeBuffer(ByteBuffer buffer) throws IOException { |
| if (buffer.remaining() < BUFFER_SIZE) { |
| write(buffer.array(), buffer.position(), buffer.remaining()); |
| } else { // append w/o copying bytes |
| ByteBuffer dup = buffer.duplicate(); |
| dup.position(buffer.limit()); // ready for flip |
| buffers.add(dup); |
| } |
| } |
| } |