com.generallycloud.baseio.codec.fixedlength.FixedLengthProtocolDecoder Maven / Gradle / Ivy
/*
* Copyright 2015-2017 GenerallyCloud.com
*
* Licensed 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 com.generallycloud.baseio.codec.fixedlength;
import java.io.IOException;
import com.generallycloud.baseio.buffer.ByteBuf;
import com.generallycloud.baseio.codec.fixedlength.future.FixedLengthReadFutureImpl;
import com.generallycloud.baseio.component.SocketSession;
import com.generallycloud.baseio.protocol.ChannelReadFuture;
import com.generallycloud.baseio.protocol.ProtocolDecoder;
/**
*
* B0 - B3：
* +-----------------+-----------------+-----------------+-----------------+
* | B0 B1 B2 B3 |
* + - - - - - - - - + - - - - - - - - + - - - - - - - - + - - - - - - - - +
* | 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 |
* | - - - - - - - - + - - - - - - - - + - - - - - - - - + - - - - - - - - +
* | |
* | Data-length(P0-P31) |
* | |
* | |
* +-----------------+-----------------+-----------------+-----------------+
*
* Data-length:-1表示心跳PING,-2表示心跳PONG,正数为报文长度
* 注意: 无论是否是心跳报文，报文头长度固定为4个字节
*
*
*/
public class FixedLengthProtocolDecoder implements ProtocolDecoder {
public static final int PROTOCOL_HEADER = 4;
public static final int PROTOCOL_PING = -1;
public static final int PROTOCOL_PONG = -2;
private int limit;
public FixedLengthProtocolDecoder(int limit) {
this.limit = limit;
}
@Override
public ChannelReadFuture decode(SocketSession session, ByteBuf buffer) throws IOException {
return new FixedLengthReadFutureImpl(session, session.getByteBufAllocator().allocate(PROTOCOL_HEADER), limit);
}
}