Varint21LengthFieldPrepender.java

package net.md_5.bungee.protocol;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import io.netty.channel.ChannelHandler;

@ChannelHandler.Sharable
public class Varint21LengthFieldPrepender extends MessageToByteEncoder<ByteBuf>
{

    @Override
    protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) throws Exception
    {
        int bodyLen = msg.readableBytes();
        int headerLen = varintSize( bodyLen );
        out.ensureWritable( headerLen + bodyLen );

        DefinedPacket.writeVarInt( bodyLen, out );
        out.writeBytes( msg );
    }

    private static int varintSize(int paramInt)
    {
        if ( ( paramInt & 0xFFFFFF80 ) == 0 )
        {
            return 1;
        }
        if ( ( paramInt & 0xFFFFC000 ) == 0 )
        {
            return 2;
        }
        if ( ( paramInt & 0xFFE00000 ) == 0 )
        {
            return 3;
        }
        if ( ( paramInt & 0xF0000000 ) == 0 )
        {
            return 4;
        }
        return 5;
    }
}