Quadcap Embeddable Database

com/quadcap/sql/file/RandomAccessOutputStream.java

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package com.quadcap.sql.file;

/* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.IOException;
import java.io.OutputStream;

import com.quadcap.util.Debug;
import com.quadcap.util.Util;

/**
 * An output stream attached to a <code>RandomAccess</code> object.
 *
 * @author Stan Bailes
 */
public class RandomAccessOutputStream extends OutputStream {
    RandomAccess                ra;
    int                         position;
    byte[]                      buf = new byte[1];
    
    public RandomAccessOutputStream(RandomAccess ra) {
        this.ra = ra;
        this.position = 0;
    }

    public int getPosition() { return position; }
    public void setPosition(int p) { position = p; }
    public long size() { return ra.size(); }
    public void resize(long size) throws IOException {
        ra.resize(size);
    }

    /**
     * Writes the specified byte to this output stream. 
     * <p>
     * Subclasses of <code>OutputStream</code> must provide an 
     * implementation for this method. 
     *
     * @param      b   the <code>byte</code>.
     * @exception  IOException  if an I/O error occurs.
     */
    public void write(int b) throws IOException {
        buf[0] = (byte)b;
        write(buf, 0, buf.length);
    }

    /**
     * Writes <code>b.length</code> bytes from the specified byte array 
     * to this output stream. 
     * <p>
     * The <code>write</code> method of <code>OutputStream</code> calls 
     * the <code>write</code> method of three arguments with the three 
     * arguments <code>b</code>, <code>0</code>, and 
     * <code>b.length</code>. 
     *
     * @param      b   the data.
     * @exception  IOException  if an I/O error occurs.
     */
    public void write(byte b[]) throws IOException {
        write(b, 0, b.length);
    }

    /**
     * Writes <code>len</code> bytes from the specified byte array 
     * starting at offset <code>off</code> to this output stream. 
     * <p>
     * The <code>write</code> method of <code>OutputStream</code> calls 
     * the write method of one argument on each of the bytes to be 
     * written out. Subclasses are encouraged to override this method and 
     * provide a more efficient implementation. 
     *
     * @param      b     the data.
     * @param      off   the start offset in the data.
     * @param      len   the number of bytes to write.
     * @exception  IOException  if an I/O error occurs.
     */
    public void write(byte b[], int off, int len) throws IOException {
        if (position + len > ra.size()) ra.resize(position + len);
        ra.write(position, b, off, len);
        position += len;
    }

    /**
     * Flushes this output stream and forces any buffered output bytes 
     * to be written out. 
     * <p>
     * The <code>flush</code> method of <code>RandomAccessOutputStream</code>
     * does nothing.  Perhaps we could call the flush method of the underlying
     * BlockFile?
     *
     * @exception  IOException  if an I/O error occurs.
     */
    public void flush() throws IOException {
    }

    /**
     * Closes this output stream and releases any system resources 
     * associated with this stream. 
     * <p>
     * The <code>close</code> method of <code>OutputStream</code> does nothing.
     *
     * @exception  IOException  if an I/O error occurs.
     */
    public void close() throws IOException {
        ra.close();
    }
}