2008-08-08 02:37:18 +02:00
|
|
|
/*
|
2012-06-04 22:31:44 +02:00
|
|
|
* Copyright 2012 The Netty Project
|
2008-08-08 02:37:18 +02:00
|
|
|
*
|
2011-12-09 06:18:34 +01:00
|
|
|
* 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:
|
2008-08-08 02:37:18 +02:00
|
|
|
*
|
2012-06-04 22:31:44 +02:00
|
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
2008-08-08 03:27:24 +02:00
|
|
|
*
|
2009-08-28 09:15:49 +02:00
|
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
2011-12-09 06:18:34 +01:00
|
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
2009-08-28 09:15:49 +02:00
|
|
|
* License for the specific language governing permissions and limitations
|
|
|
|
* under the License.
|
2008-08-08 02:37:18 +02:00
|
|
|
*/
|
2011-12-09 04:38:59 +01:00
|
|
|
package io.netty.example.factorial;
|
2008-08-08 02:37:18 +02:00
|
|
|
|
2011-12-09 04:38:59 +01:00
|
|
|
import io.netty.buffer.ChannelBuffer;
|
2012-06-07 07:52:33 +02:00
|
|
|
import io.netty.channel.ChannelHandlerContext;
|
2012-05-16 16:02:06 +02:00
|
|
|
import io.netty.handler.codec.CorruptedFrameException;
|
2012-05-29 09:06:00 +02:00
|
|
|
import io.netty.handler.codec.StreamToMessageDecoder;
|
|
|
|
|
|
|
|
import java.math.BigInteger;
|
2008-08-08 02:37:18 +02:00
|
|
|
|
|
|
|
/**
|
2010-02-02 04:13:15 +01:00
|
|
|
* Decodes the binary representation of a {@link BigInteger} prepended
|
|
|
|
* with a magic number ('F' or 0x46) and a 32-bit integer length prefix into a
|
|
|
|
* {@link BigInteger} instance. For example, { 'F', 0, 0, 0, 1, 42 } will be
|
|
|
|
* decoded into new BigInteger("42").
|
2008-08-08 02:37:18 +02:00
|
|
|
*/
|
2012-05-29 09:06:00 +02:00
|
|
|
public class BigIntegerDecoder extends StreamToMessageDecoder<BigInteger> {
|
2008-08-08 02:37:18 +02:00
|
|
|
|
|
|
|
@Override
|
2012-06-07 07:52:33 +02:00
|
|
|
public BigInteger decode(ChannelHandlerContext ctx, ChannelBuffer in) {
|
2008-08-12 13:58:15 +02:00
|
|
|
// Wait until the length prefix is available.
|
2012-05-29 09:06:00 +02:00
|
|
|
if (in.readableBytes() < 5) {
|
2008-08-08 02:37:18 +02:00
|
|
|
return null;
|
|
|
|
}
|
2009-07-23 11:05:53 +02:00
|
|
|
|
2012-05-29 09:06:00 +02:00
|
|
|
in.markReaderIndex();
|
2010-02-02 04:13:15 +01:00
|
|
|
|
|
|
|
// Check the magic number.
|
2012-05-29 09:06:00 +02:00
|
|
|
int magicNumber = in.readUnsignedByte();
|
2010-02-02 04:13:15 +01:00
|
|
|
if (magicNumber != 'F') {
|
2012-05-29 09:06:00 +02:00
|
|
|
in.resetReaderIndex();
|
2010-02-02 04:13:15 +01:00
|
|
|
throw new CorruptedFrameException(
|
|
|
|
"Invalid magic number: " + magicNumber);
|
|
|
|
}
|
2008-08-08 02:37:18 +02:00
|
|
|
|
2008-08-12 13:58:15 +02:00
|
|
|
// Wait until the whole data is available.
|
2012-05-29 09:06:00 +02:00
|
|
|
int dataLength = in.readInt();
|
|
|
|
if (in.readableBytes() < dataLength) {
|
|
|
|
in.resetReaderIndex();
|
2008-08-08 02:37:18 +02:00
|
|
|
return null;
|
|
|
|
}
|
|
|
|
|
2008-08-12 13:58:15 +02:00
|
|
|
// Convert the received data into a new BigInteger.
|
2008-08-08 02:37:18 +02:00
|
|
|
byte[] decoded = new byte[dataLength];
|
2012-05-29 09:06:00 +02:00
|
|
|
in.readBytes(decoded);
|
2008-08-08 02:37:18 +02:00
|
|
|
|
|
|
|
return new BigInteger(decoded);
|
|
|
|
}
|
|
|
|
}
|