/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.cassandra.io.util;

import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;


/**
 * An implementation of the DataOutputStream interface. This class is completely thread
 * unsafe.
 */
public class DataOutputBuffer extends DataOutputStream
{
    private static class Buffer extends ByteArrayOutputStream
    {
        public byte[] getData()
        {
            return buf;
        }
        
        public int getLength()
        {
            return count;
        }
        
        public void reset()
        {
            count = 0;
        }
        
        public void write(DataInput in, int len) throws IOException
        {
            int newcount = count + len;
            if (newcount > buf.length)
            {
                byte newbuf[] = new byte[Math.max(buf.length << 1, newcount)];
                System.arraycopy(buf, 0, newbuf, 0, count);
                buf = newbuf;
            }
            in.readFully(buf, count, len);
            count = newcount;
        }

        public Buffer()
        {
        }

        public Buffer(int size)
        {
            super(size);
        }
    }
    
    private Buffer buffer;
    
    /** Constructs a new empty buffer. */
    public DataOutputBuffer()
    {
        this(new Buffer());
    }
    
    public DataOutputBuffer(int size)
    {
        this(new Buffer(size));
    }

    private DataOutputBuffer(Buffer buffer)
    {
        super(buffer);
        this.buffer = buffer;
    }
    
    /**
     * Returns the current contents of the buffer. Data is only valid to
     * {@link #getLength()}.
     */
    public byte[] getData()
    {
        return buffer.getData();
    }
    
    /** Returns the length of the valid data currently in the buffer. */
    public int getLength()
    {
        return buffer.getLength();
    }
    
    /** Resets the buffer to empty. */
    public DataOutputBuffer reset()
    {
        this.written = 0;
        buffer.reset();
        return this;
    }
    
    /** Writes bytes from a DataInput directly into the buffer. */
    public void write(DataInput in, int length) throws IOException
    {
        buffer.write(in, length);
    }   
}