Bitmap.java

/* ====================================================================
   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
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package org.apache.poi.hslf.blip;

import java.awt.Dimension;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;

import org.apache.commons.io.input.UnsynchronizedByteArrayInputStream;
import org.apache.poi.ddf.EscherBSERecord;
import org.apache.poi.ddf.EscherContainerRecord;
import org.apache.poi.hslf.record.RecordAtom;
import org.apache.poi.hslf.usermodel.HSLFPictureData;
import org.apache.poi.util.IOUtils;
import org.apache.poi.util.Internal;
import org.apache.poi.util.Units;

/**
 * Represents a bitmap picture data:  JPEG or PNG.
 * The data is not compressed and the exact file content is written in the stream.
 */
public abstract class Bitmap extends HSLFPictureData {

    /**
     * Creates a new instance.
     *
     * @param recordContainer Record tracking all pictures. Should be attached to the slideshow that this picture is
     *                        linked to.
     * @param bse Record referencing this picture. Should be attached to the slideshow that this picture is linked to.
     */
    @Internal
    protected Bitmap(EscherContainerRecord recordContainer, EscherBSERecord bse) {
        super(recordContainer, bse);
    }

    @Override
    public byte[] getData(){
        byte[] rawdata = getRawData();
        int prefixLen = 16*getUIDInstanceCount()+1;
        return IOUtils.safelyClone(rawdata, prefixLen, rawdata.length-prefixLen, rawdata.length);
    }

    @Override
    protected byte[] formatImageForSlideshow(byte[] data) {
        byte[] checksum = getChecksum(data);
        long rawDataSize = calcRawDataSize(getUIDInstanceCount(), checksum.length, data.length);
        byte[] rawData = IOUtils.safelyAllocate(rawDataSize, RecordAtom.getMaxRecordLength());
        int offset = 0;

        System.arraycopy(checksum, 0, rawData, offset, checksum.length);
        offset += checksum.length;

        if (getUIDInstanceCount() == 2) {
            System.arraycopy(checksum, 0, rawData, offset, checksum.length);
            offset += checksum.length;
        }

        offset++;
        System.arraycopy(data, 0, rawData, offset, data.length);
        return rawData;
    }

    /**
     * Calculates the size in bytes of the raw data array produced by {@link #formatImageForSlideshow}.
     * Exposed for testing overflow safety.
     *
     * @param uidInstanceCount UID instance count (1 or 2)
     * @param checksumLength   length of the MD5 checksum array
     * @param dataLength       length of the image data array
     * @return required buffer size as a {@code long} to avoid integer overflow
     * @throws ArithmeticException if there is an overflow
     */
    static long calcRawDataSize(int uidInstanceCount, int checksumLength, int dataLength) {
        final long multiplicand = (long) checksumLength * uidInstanceCount;
        return Math.addExact(multiplicand, 1L + dataLength);
    }

    @Override
    public Dimension getImageDimension() {
        try (InputStream is = UnsynchronizedByteArrayInputStream.builder().setByteArray(getData()).get()){
            BufferedImage bi = ImageIO.read(is);
            return new Dimension(
                (int)Units.pixelToPoints(bi.getWidth()),
                (int)Units.pixelToPoints(bi.getHeight())
            );
        } catch (IOException e) {
            return new Dimension(200,200);
        }
    }
}