/*
* Copyright 2011 The Netty Project
*
* The Netty Project 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:
*
* 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 io.netty.handler.codec.bytes;
import io.netty.buffer.ChannelBuffer;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.MessageEvent;
import io.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.frame.LengthFieldPrepender;
import io.netty.handler.codec.oneone.OneToOneDecoder;
/**
* Decodes a received {@link ChannelBuffer} into an array of bytes.
* A typical setup for TCP/IP would be:
* <pre>
* {@link ChannelPipeline} pipeline = ...;
*
* // Decoders
* pipeline.addLast("frameDecoder",
* new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4));
* pipeline.addLast("bytesDecoder",
* new {@link ByteArrayDecoder}());
*
* // Encoder
* pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4));
* pipeline.addLast("bytesEncoder", new {@link ByteArrayEncoder}());
* </pre>
* and then you can use an array of bytes instead of a {@link ChannelBuffer}
* as a message:
* <pre>
* void messageReceived({@link ChannelHandlerContext} ctx, {@link MessageEvent} e) {
* byte[] bytes = (byte[]) e.getMessage();
* ...
* }
* </pre>
*/
public class ByteArrayDecoder extends OneToOneDecoder {
@Override
protected Object decode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
if (!(msg instanceof ChannelBuffer)) {
return msg;
}
ChannelBuffer buf = (ChannelBuffer) msg;
byte[] array;
if (buf.hasArray()) {
if (buf.arrayOffset() == 0 && buf.readableBytes() == buf.capacity()) {
// we have no offset and the length is the same as the capacity. Its safe to reuse the array without copy it first
array = buf.array();
} else {
// copy the ChannelBuffer to a byte array
array = new byte[buf.readableBytes()];
buf.getBytes(0, array);
}
} else {
// copy the ChannelBuffer to a byte array
array = new byte[buf.readableBytes()];
buf.getBytes(0, array);
}
return array;
}
}