DataInputBuffer.java

package org.apache.cassandra.io.util;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.IOException;

public class DataInputBuffer extends DataInputStream
{
    private static class Buffer extends ByteArrayInputStream
    {
        public Buffer(byte[] buf, int offset, int length)
        {
            super(buf, offset, length);
        }

        public void setData(byte[] buf)
        {
            this.buf = buf;
        }
        
        public void setLength(int count)
        {
            this.count = count;
        }
        
        public void reset()
        {
            count = 0;
        }
        
        public byte[] read(DataOutput out, int len) throws IOException
        {
            int newcount = count + len;
            byte newbuf[] = null;
            if (newcount > buf.length)
            {
                newbuf = new byte[Math.max(buf.length << 1, newcount)];
                System.arraycopy(buf, 0, newbuf, 0, count);
                buf = newbuf;
            }
            out.write(buf, count, len);
            count = newcount;
            
            return newbuf;
        }
    }
    
    private Buffer buffer;
    
    public DataInputBuffer(byte[] buf, int offset, int length)
    {
        this(new Buffer(buf, offset, length));
    }
    
    private DataInputBuffer(Buffer buffer)
    {
        super(buffer);
        this.buffer = buffer;
    }
    
    public void setData(byte[] buf)
    {
        buffer.setData(buf);
    }
    
    public void setLength(int length)
    {
        buffer.setLength(length);
    }
    
    public void reset()
    {
        buffer.reset();
    }
    
    public byte[] read(DataOutput out, int length) throws IOException
    {
        return buffer.read(out, length);
    }
}