001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.io.output;
018
019import java.io.FilterOutputStream;
020import java.io.IOException;
021import java.io.OutputStream;
022
023import org.apache.commons.io.IOUtils;
024
025/**
026 * OutputStream which breaks larger output blocks into chunks.
027 * Native code may need to copy the input array; if the write buffer
028 * is very large this can cause OOME.
029 *
030 * @since 2.5
031 */
032public class ChunkedOutputStream extends FilterOutputStream {
033
034    /**
035     * The maximum chunk size to us when writing data arrays
036     */
037    private final int chunkSize;
038
039    /**
040     * Creates a new stream that uses a chunk size of {@link IOUtils#DEFAULT_BUFFER_SIZE}.
041     *
042     * @param stream the stream to wrap
043     */
044    public ChunkedOutputStream(final OutputStream stream) {
045        this(stream, IOUtils.DEFAULT_BUFFER_SIZE);
046    }
047
048    /**
049     * Creates a new stream that uses the specified chunk size.
050     *
051     * @param stream the stream to wrap
052     * @param chunkSize the chunk size to use; must be a positive number.
053     * @throws IllegalArgumentException if the chunk size is <= 0
054     */
055    public ChunkedOutputStream(final OutputStream stream, final int chunkSize) {
056       super(stream);
057       if (chunkSize <= 0) {
058           throw new IllegalArgumentException();
059       }
060       this.chunkSize = chunkSize;
061    }
062
063    /**
064     * Writes the data buffer in chunks to the underlying stream
065     *
066     * @param data the data to write
067     * @param srcOffset the offset
068     * @param length the length of data to write
069     *
070     * @throws IOException if an I/O error occurs.
071     */
072    @Override
073    public void write(final byte[] data, final int srcOffset, final int length) throws IOException {
074        int bytes = length;
075        int dstOffset = srcOffset;
076        while(bytes > 0) {
077            final int chunk = Math.min(bytes, chunkSize);
078            out.write(data, dstOffset, chunk);
079            bytes -= chunk;
080            dstOffset += chunk;
081        }
082    }
083
084}