2008-08-08 02:37:18 +02:00
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/*
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2012-06-04 22:31:44 +02:00
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* Copyright 2012 The Netty Project
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2008-08-08 02:37:18 +02:00
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*
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2011-12-09 06:18:34 +01:00
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the 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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2012-06-04 22:31:44 +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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2011-12-09 06:18:34 +01:00
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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2009-08-28 09:15:49 +02:00
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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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2011-12-09 04:38:59 +01:00
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package io.netty.example.factorial;
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2008-08-08 02:37:18 +02:00
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2012-06-10 04:08:43 +02:00
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import io.netty.buffer.ByteBuf;
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2012-06-07 07:52:33 +02:00
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import io.netty.channel.ChannelHandlerContext;
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2012-06-09 14:05:59 +02:00
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import io.netty.handler.codec.ByteToMessageDecoder;
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2012-06-11 16:04:04 +02:00
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import io.netty.handler.codec.CorruptedFrameException;
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2012-05-29 09:06:00 +02:00
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import java.math.BigInteger;
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2008-08-08 02:37:18 +02:00
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/**
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2010-02-02 04:13:15 +01:00
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* Decodes the binary representation of a {@link BigInteger} prepended
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* with a magic number ('F' or 0x46) and a 32-bit integer length prefix into a
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* {@link BigInteger} instance. For example, { 'F', 0, 0, 0, 1, 42 } will be
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* decoded into new BigInteger("42").
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2008-08-08 02:37:18 +02:00
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*/
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2013-01-08 08:18:46 +01:00
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public class BigIntegerDecoder extends ByteToMessageDecoder {
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2008-08-08 02:37:18 +02:00
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@Override
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2019-12-16 21:00:32 +01:00
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protected void decode(ChannelHandlerContext ctx, ByteBuf in) {
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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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2012-05-29 09:06:00 +02:00
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if (in.readableBytes() < 5) {
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2013-04-03 11:32:33 +02:00
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return;
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2008-08-08 02:37:18 +02:00
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}
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2009-07-23 11:05:53 +02:00
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2018-12-11 14:00:49 +01:00
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int readerIndex = in.readerIndex();
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2010-02-02 04:13:15 +01:00
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// Check the magic number.
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2012-05-29 09:06:00 +02:00
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int magicNumber = in.readUnsignedByte();
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2010-02-02 04:13:15 +01:00
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if (magicNumber != 'F') {
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2018-12-11 14:00:49 +01:00
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in.readerIndex(readerIndex);
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2014-05-23 09:46:31 +02:00
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throw new CorruptedFrameException("Invalid magic number: " + magicNumber);
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2010-02-02 04:13:15 +01:00
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}
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2008-08-08 02:37:18 +02:00
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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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2012-05-29 09:06:00 +02:00
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int dataLength = in.readInt();
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if (in.readableBytes() < dataLength) {
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2018-12-11 14:00:49 +01:00
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in.readerIndex(readerIndex);
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2013-04-03 11:32:33 +02:00
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return;
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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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// 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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2012-05-29 09:06:00 +02:00
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in.readBytes(decoded);
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2008-08-08 02:37:18 +02:00
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2019-12-16 21:00:32 +01:00
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ctx.fireChannelRead(new BigInteger(decoded));
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2008-08-08 02:37:18 +02:00
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}
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}
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