Quadcap Embeddable Database

com/quadcap/sql/file/ByteArrayRandomAccess.java

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package com.quadcap.sql.file;

/* Copyright 1999 - 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 com.quadcap.util.Debug;
import com.quadcap.util.Util;

/**
 * A <code>RandomAccess</code> implementation using a byte array.
 *
 * @author Stan Bailes
 */
public class ByteArrayRandomAccess extends RandomAccess {
    byte[]                      buf;
    int                         size;

    public ByteArrayRandomAccess() {
        this.size = 0;
        setCapacity(1024);
    }

    public ByteArrayRandomAccess(int initialCap) {
        this.size = 0;
        setCapacity(initialCap);
    }

    public ByteArrayRandomAccess(byte[] buf) {
        this.buf = buf;
        this.size = buf.length;
    }

    public void reset(byte[] buf, int size) {
        this.buf = buf;
        this.size = size;
    }

    public byte[] getBytes() {
        return buf;
    }

    final void setCapacity(long cap) {
        if (buf == null || cap > buf.length) {
            byte[] nbuf = new byte[(int)cap];
            if (size > 0) {
                System.arraycopy(buf, 0, nbuf, 0, size);
            }
            this.buf = nbuf;
        }
    }

    public byte[] toByteArray() {
        byte[] ret = new byte[size];
        read(0, ret, 0, size);
        return ret;
    }

    /**
     * Return the size of the managed region.
     */
    public long size() {
        return size;
    }

    /**
     * Resize the managed region.
     */
    public void resize(long newSize) {
        if (newSize > buf.length) {
            setCapacity(newSize + (newSize >> 1));
        }
        this.size = (int)newSize;
    }

    /* Write <tt>len</tt> bytes from position <tt>offset</tt> in buffer
     * <tt>buf</tt> to position <tt>pos</tt> bytes into the managed
     * area.
     */
    public void write(long pos, byte[] b, int offset, int len) {
        //#ifdef DEBUG
        if (trace) {
            Debug.println("BAR:write(" + pos + ", " +
                          Util.hexBytes(b,offset,len) + ")");
        }
        //#endif
        System.arraycopy(b, offset, buf, (int)pos, len);
    }

    /**
     * Read <tt>len</tt> bytes from location <tt>pos</tt> of the region
     * into the buffer <tt>buf</tt>, starting at <tt>offset</tt>.
     */
    public void read(long pos, byte[] b, int offset, int len) {
        //#ifdef DEBUG
        if (trace) {
            Debug.println("BAR:read(" + pos + ", " +
                          Util.hexBytes(b,offset,len) + ")");
        }
        //#endif
        System.arraycopy(buf, (int)pos, b, offset, len);
    }

    //#ifdef DEBUG
    static final boolean trace = false;
    //#endif

    public final void writeByte(int pos, int val) {
        buf[pos] = (byte)(val & 0xff);
    }

    public final int readByte(int pos) {
        return buf[pos] & 0xff;
    }

    /**
     * Finalization...
     */
    public void close() {
    }

    public void flush() {
    }
}