OnDemandResponseEncoder.java

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package dev.advo.fs.net.ondemand;
 
 
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
 
import dev.advo.fs.fs.FileDescriptor;
 
public final class OnDemandResponseEncoder extends OneToOneEncoder {
 
    @Override
    protected Object encode(ChannelHandlerContext ctx, Channel c, Object msg) throws Exception {
        if (msg instanceof OnDemandResponse) {
            OnDemandResponse resp = (OnDemandResponse) msg;
            
            FileDescriptor fileDescriptor = resp.getFileDescriptor();
            int fileSize = resp.getFileSize();
            ChannelBuffer chunkData = resp.getChunkData();
            
            ChannelBuffer buf = ChannelBuffers.buffer(7 + chunkData.readableBytes());           
            buf.writeMedium(create(fileDescriptor.getType(), fileDescriptor.getFile()));
            buf.writeInt(fileSize);
            buf.writeBytes(chunkData);
            
            return buf;
        }
        return msg;
    }
 
      public static int create(int index, int file) {
            if ((index & 0xFFFFFFE0) != 0)
              throw new IllegalArgumentException("invalid index " + index + ":" + file); 
            if ((file & 0xFFF80000) != 0)
              throw new IllegalArgumentException("invalid file " + index + ":" + file); 
            return index & 0x1F | (file & 0x7FFFF) << 5;
          }
}