/*
 * Copyright (c) 1997-1999 The Java Apache Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Java Apache 
 *    Project for use in the Apache JServ servlet engine project
 *    <http://java.apache.org/>."
 *
 * 4. The names "Apache JServ", "Apache JServ Servlet Engine" and 
 *    "Java Apache Project" must not be used to endorse or promote products 
 *    derived from this software without prior written permission.
 *
 * 5. Products derived from this software may not be called "Apache JServ"
 *    nor may "Apache" nor "Apache JServ" appear in their names without 
 *    prior written permission of the Java Apache Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Java Apache 
 *    Project for use in the Apache JServ servlet engine project
 *    <http://java.apache.org/>."
 *    
 * THIS SOFTWARE IS PROVIDED BY THE JAVA APACHE PROJECT "AS IS" AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE JAVA APACHE PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Java Apache Group. For more information
 * on the Java Apache Project and the Apache JServ Servlet Engine project,
 * please see <http://java.apache.org/>.
 *
 */

package org.apache.java.io;

import java.io.*;

/**
 * This class implements an input stream whose read() methods
 * perform a full reading of the requested length.
 *
 * @author <a href="mailto:trung.tranduc@prague.ixos.cz">Trung Tran-Duc</a>
 * @author <a href="mailto:simon.levitt@uk.worldpay.com">Simon Levitt</a>
 * @version $Revision: 1.5 $ $Date: 1999/04/26 00:33:55 $
 */
public class ReadFullyInputStream extends FilterInputStream {

    /**
     * Default Constructor
     */
    public ReadFullyInputStream(InputStream in) {
        super(in);
    }

    /**
     * Fill given byte array with bytes read from the stream and return
     * only when all the array has been filled.
     */
    public int read(byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    /**
     * Fill given byte array with bytes read from the stream and return
     * only when all the array has been filled.
     */
    public int read(byte[] b, int off, int len) throws IOException {
        int count = 0;
        while (len > 0) {
            int rc = super.read(b, off, len);
            if (rc < 0) {
                count = (count > 0) ? count : -1;
                break;
            }
            off += rc;
            len -= rc;
            count += rc;
        }
        return count;
    }
}
