2008-08-08 02:37:18 +02:00
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/*
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2009-08-28 09:15:49 +02:00
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* Copyright 2009 Red Hat, Inc.
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2008-08-08 02:37:18 +02:00
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*
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2009-08-28 09:15:49 +02:00
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* Red Hat licenses this file to you under the Apache License, version 2.0
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* (the "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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2008-08-08 02:37:18 +02:00
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*
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2009-08-28 09:15:49 +02:00
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* http://www.apache.org/licenses/LICENSE-2.0
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2008-08-08 03:27:24 +02:00
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*
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2009-08-28 09:15:49 +02:00
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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2008-08-08 02:37:18 +02:00
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*/
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2008-08-08 03:40:10 +02:00
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package org.jboss.netty.example.factorial;
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2008-08-08 02:37:18 +02:00
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import java.math.BigInteger;
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2008-08-08 03:40:10 +02:00
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import org.jboss.netty.buffer.ChannelBuffer;
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import org.jboss.netty.channel.Channel;
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import org.jboss.netty.channel.ChannelHandlerContext;
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import org.jboss.netty.handler.codec.frame.FrameDecoder;
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2008-08-08 02:37:18 +02:00
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/**
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2008-08-12 13:58:15 +02:00
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* Decodes the binary representation of a {@link BigInteger} with 32-bit
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* integer length prefix into a Java {@link BigInteger} instance. For example,
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* { 0, 0, 0, 1, 42 } will be decoded into new BigInteger("42").
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*
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2008-08-08 03:27:24 +02:00
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* @author The Netty Project (netty-dev@lists.jboss.org)
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2009-10-14 07:46:40 +02:00
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* @author Trustin Lee (trustin@gmail.com)
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2008-08-08 02:37:18 +02:00
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*
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* @version $Rev$, $Date$
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*/
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public class BigIntegerDecoder extends FrameDecoder {
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@Override
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protected Object decode(
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ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
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2008-08-12 13:58:15 +02:00
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// Wait until the length prefix is available.
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2008-08-08 02:37:18 +02:00
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if (buffer.readableBytes() < 4) {
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return null;
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}
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2009-07-23 11:05:53 +02:00
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2008-08-08 02:37:18 +02:00
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int dataLength = buffer.getInt(buffer.readerIndex());
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2008-08-12 13:58:15 +02:00
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// Wait until the whole data is available.
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2008-08-08 02:37:18 +02:00
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if (buffer.readableBytes() < dataLength + 4) {
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return null;
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}
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2008-08-12 13:58:15 +02:00
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// Skip the length field because we know it already.
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2008-08-08 02:37:18 +02:00
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buffer.skipBytes(4);
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2008-08-12 13:58:15 +02:00
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// Convert the received data into a new BigInteger.
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2008-08-08 02:37:18 +02:00
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byte[] decoded = new byte[dataLength];
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buffer.readBytes(decoded);
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return new BigInteger(decoded);
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}
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}
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