Jtt1078Decoder.java
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package cn.org.hentai.jtt1078.server;
import cn.org.hentai.jtt1078.util.ByteHolder;
import cn.org.hentai.jtt1078.util.ByteUtils;
import cn.org.hentai.jtt1078.util.Packet;
/**
* Created by matrixy on 2019/4/9.
*/
public class Jtt1078Decoder
{
ByteHolder buffer = new ByteHolder(4096);
public void write(byte[] block)
{
buffer.write(block);
}
public void write(byte[] block, int startIndex, int length)
{
byte[] buff = new byte[length];
System.arraycopy(block, startIndex, buff, 0, length);
write(buff);
}
public Packet decode()
{
if (this.buffer.size() < 30) return null;
if ((buffer.getInt(0) & 0x7fffffff) != 0x30316364)
{
String header = ByteUtils.toString(buffer.array(30));
throw new RuntimeException("invalid protocol header: " + header);
}
int lengthOffset = 28;
int dataType = (this.buffer.get(15) >> 4) & 0x0f;
// 透传数据类型：0100，没有后面的时间以及Last I Frame Interval和Last Frame Interval字段
if (dataType == 0x04) lengthOffset = 28 - 8 - 2 - 2;
else if (dataType == 0x03) lengthOffset = 28 - 4;
int bodyLength = this.buffer.getShort(lengthOffset);
int packetLength = bodyLength + lengthOffset + 2;
if (this.buffer.size() < packetLength) return null;
byte[] block = new byte[packetLength];
this.buffer.sliceInto(block, packetLength);
return Packet.create(block);
}
}