/*

   Derby - Class org.apache.derby.impl.store.raw.data.BufferedByteHolderInputStream

   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.derby.impl.store.raw.data;

import java.io.IOException;

public abstract class BufferedByteHolderInputStream
extends ByteHolderInputStream
{
	public BufferedByteHolderInputStream(ByteHolder bh) {
		super(bh);
	}

	public abstract void fillByteHolder() throws IOException;

	public int read() throws IOException
	{
		fillByteHolder();
		return super.read();
	}

	public int read(byte b[], int off, int len)
		 throws IOException
	{
		fillByteHolder();
		return super.read(b,off,len);
	}

	public long skip(long count) throws IOException
	{
		long bytesSkipped = 0L;
		while (bytesSkipped < count) {
			fillByteHolder();
			long skipped = super.skip(count - bytesSkipped);
			if (skipped <= 0L) {
				break;
			}
			bytesSkipped += skipped;
		}
		return bytesSkipped;
	}

	public int available() throws IOException
	{
		fillByteHolder();
		return super.available(); 
	}
}