path: root/src/java/org/apache/fop/util/StreamUtilities.java

/*
 * $Id: StreamUtilities.java,v 1.3 2003/03/07 10:09:50 jeremias Exp $
 * ============================================================================
 *                    The Apache Software License, Version 1.1
 * ============================================================================
 * 
 * Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, 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. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment: "This product includes software
 *    developed by the Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself, if
 *    and wherever such third-party acknowledgments normally appear.
 * 
 * 4. The names "FOP" and "Apache Software Foundation" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    apache@apache.org.
 * 
 * 5. Products derived from this software may not be called "Apache", nor may
 *    "Apache" appear in their name, without prior written permission of the
 *    Apache Software Foundation.
 * 
 * THIS SOFTWARE IS PROVIDED ``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
 * APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
 * DING, 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 Apache Software Foundation and was originally created by
 * James Tauber <jtauber@jtauber.com>. For more information on the Apache
 * Software Foundation, please see <http://www.apache.org/>.
 */ 
package org.apache.fop.util;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.EOFException;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.zip.CRC32;

/**
 * General handy stream i/o methods.
 */
public class StreamUtilities {

    /**
     * Size of buffers. Duh.
     */
    public static final int BUFFER_SIZE = 4096; // cuz I like big buffers...

    /**
     * Binary copies bytes from an input stream to an output stream.
     * The process is buffered, so you shouldn't need
     * BufferedInput/OutputStreams. Flushes when it's finished, but does
     * not close either stream. Returns the number of bytes copied.
     * @param source InputStream to read from
     * @param sink OutputStream to write to
     * @return long the total number of bytes copied
     * @throws IOException In case of an I/O problem
     */
    public static long streamCopy(InputStream source,
                                  OutputStream sink) throws IOException {
        // set table
        byte[] buffer = new byte[BUFFER_SIZE];
        long total = 0;

        // trough
        int scoop;
        while ((scoop = source.read(buffer)) >= 0) {
            if (scoop == 0) {
                System.out.println("zero scoop!");
            }
            sink.write(buffer, 0, scoop);
            total += scoop;
        }

        // do dishes
        sink.flush();

        return total;
    }

    /**
     * Method streamCopy.
     */
    /**
     * Binary copies up to the given number of bytes from an input
     * stream to an output stream. The process is buffered, so you
     * shouldn't need BufferedInput/OutputStreams.
     * Flushes when it's finished, but does not close either stream.
     * Throws an EOFExeption if there aren't enough bytes available to
     * transfer the requested amount.
     * @param source InputStream to read from
     * @param sink OutputStream to write to
     * @param howMany requested amount of bytes that are to be copied
     * @return long the total number of bytes copied
     * @throws IOException In case of an I/O problem
     */
    public static long streamCopy(InputStream source,
                                  OutputStream sink, int howMany) throws IOException {
        // set table
        byte[] buffer = new byte[BUFFER_SIZE];
        int left = howMany;

        // trough
        int scoop;
        while (left > 0) {
            scoop = source.read(buffer, 0, Math.min(BUFFER_SIZE, left));
            if (scoop < 0) {
                throw new EOFException(
                  "Not enough bytes to feed you in "
                  + "IOLib.streamCopy(source, sink, howMany); you asked for " 
                  + howMany + " and I only have " + (howMany - left));
            }

            sink.write(buffer, 0, scoop);
            left -= scoop;
        }

        // do dishes
        sink.flush();

        return howMany;
    }

    /**
     * Method streamCopyWithChecksum.
     */
    /**
     * Binary copies up to the given number of bytes from an input
     * stream to an output stream. The process is buffered, so you
     * shouldn't need BufferedInput/OutputStreams.
     * Flushes when it's finished, but does not close either stream.
     * Throws an EOFExeption if there aren't enough bytes available
     * to transfer the requested amount.
     * @param source InputStream to read from
     * @param sink OutputStream to write to
     * @param howMany requested amount of bytes that are to be copied
     * @return long the checksum of the bytes copied
     * @throws IOException In case of an I/O problem
     */
    public static long streamCopyWithChecksum(InputStream source,
            OutputStream sink, int howMany) throws IOException {
        // set table
        byte[] buffer = new byte[BUFFER_SIZE];
        int left = howMany;
        CRC32 checksummer = new CRC32();

        // trough
        int scoop;
        while (left > 0) {
            scoop = source.read(buffer, 0, Math.min(BUFFER_SIZE, left));
            if (scoop < 0) {
                throw new EOFException("Not enough bytes to feed you in "
                        + "IOLib.streamCopy(source, sink, howMany)");
            }

            checksummer.update(buffer, 0, scoop);
            sink.write(buffer, 0, scoop);
            left -= scoop;
        }

        // do dishes
        sink.flush();

        return checksummer.getValue();
    }

    /**
     * Method dataCopy.
     */
    /**
     * Binary copies up to the given number of bytes from a DataInput
     * object to an DataOutput object. The process is buffered. Since
     * DataOutput doesn't support closing or flushing, it does neither.
     * @param source DataInput to read from
     * @param sink DataOutput to write to
     * @param howMany requested amount of bytes that are to be copied
     * @return long the total number of bytes copied
     * @throws IOException In case of an I/O problem
     */
    public static long dataCopy(DataInput source, DataOutput sink,
                                int howMany) throws IOException {
        // set table
        byte[] buffer = new byte[BUFFER_SIZE];
        int left = howMany;

        // trough
        int scoop;
        while (left > 0) {
            scoop = Math.min(BUFFER_SIZE, left);
            source.readFully(buffer, 0, scoop);
            sink.write(buffer, 0, scoop);
            left -= scoop;
        }

        // do dishes
        return howMany;
    }


    /**
     * Loads the contents of the InputStream to a byte array. The InputStream 
     * isn't closed.
     * @param in InputStream to read from
     * @param initialTargetBufferSize initial number of bytes to allocate 
     *      (expected size to avoid a lot of reallocations)
     * @return byte[] the array of bytes requested
     * @throws IOException In case of an I/O problem
     */
    public static byte[] toByteArray(InputStream in, int initialTargetBufferSize) 
                throws IOException {
        ByteArrayOutputStream baout = new ByteArrayOutputStream(initialTargetBufferSize);
        try {
            streamCopy(in, baout);
        } finally {
            baout.close();
        }
        return baout.toByteArray();
    }

}