Quadcap Embeddable Server

com/quadcap/io/LimitedOutputStream.java

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package com.quadcap.io;

/* 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.*;

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

/**
 * A limited size output stream.
 *
 * @author Stan Bailes
 */

public class LimitedOutputStream extends FilterOutputStream {
    int                 count = 0;
    int                 limit;

    public LimitedOutputStream(OutputStream os, int limit) {
        super(os);
        this.limit = limit;
    }

    public void write(int b) throws IOException {
        if (count + 1 > limit) {
            throw new LimitExceededException("Stream limit (" + limit +
                                             ") exceeded");
        }
        count++;
        out.write(b);
    }

    /**
     * Writes <code>len</code> bytes from the specified 
     * <code>byte</code> array starting at offset <code>off</code> to 
     * this output stream. 
     * <p>
     * The <code>write</code> method of <code>FilterOutputStream</code> 
     * calls the <code>write</code> method of one argument on each 
     * <code>byte</code> to output. 
     * <p>
     * Note that this method does not call the <code>write</code> method 
     * of its underlying input stream with the same arguments. Subclasses 
     * of <code>FilterOutputStream</code> should provide a more efficient 
     * implementation of this method. 
     *
     * @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.
     * @see        java.io.FilterOutputStream#write(int)
     * @since      JDK1.0
     */
    public void write(byte b[], int off, int len) throws IOException {
        if (count + len > limit) {
            if (limit - count > 0) {
                out.write(b, off, limit - count);
            }
            throw new LimitExceededException("Stream limit (" + limit +
                                             ") exceeded");
        }
        count += len;
        out.write(b, off, len);
    }

}