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.imaging.formats.jpeg.segments;
018
019import static org.apache.commons.imaging.common.BinaryFunctions.read2Bytes;
020import static org.apache.commons.imaging.common.BinaryFunctions.readByte;
021import static org.apache.commons.imaging.common.BinaryFunctions.readBytes;
022import static org.apache.commons.imaging.common.BinaryFunctions.skipBytes;
023
024import java.io.ByteArrayInputStream;
025import java.io.IOException;
026import java.io.InputStream;
027
028import org.apache.commons.imaging.ImagingException;
029import org.apache.commons.imaging.formats.jpeg.JpegConstants;
030
031public final class JfifSegment extends AbstractSegment {
032    public final int jfifMajorVersion;
033    public final int jfifMinorVersion;
034    public final int densityUnits;
035    public final int xDensity;
036    public final int yDensity;
037
038    public final int xThumbnail;
039    public final int yThumbnail;
040    public final int thumbnailSize;
041
042    public JfifSegment(final int marker, final byte[] segmentData) throws ImagingException, IOException {
043        this(marker, segmentData.length, new ByteArrayInputStream(segmentData));
044    }
045
046    public JfifSegment(final int marker, final int markerLength, final InputStream is) throws ImagingException, IOException {
047        super(marker, markerLength);
048
049        final byte[] signature = readBytes(is, JpegConstants.JFIF0_SIGNATURE.size());
050        if (!JpegConstants.JFIF0_SIGNATURE.equals(signature) && !JpegConstants.JFIF0_SIGNATURE_ALTERNATIVE.equals(signature)) {
051            throw new ImagingException("Not a Valid JPEG File: missing JFIF string");
052        }
053
054        jfifMajorVersion = readByte("jfifMajorVersion", is, "Not a Valid JPEG File");
055        jfifMinorVersion = readByte("jfifMinorVersion", is, "Not a Valid JPEG File");
056        densityUnits = readByte("densityUnits", is, "Not a Valid JPEG File");
057        xDensity = read2Bytes("xDensity", is, "Not a Valid JPEG File", getByteOrder());
058        yDensity = read2Bytes("yDensity", is, "Not a Valid JPEG File", getByteOrder());
059
060        xThumbnail = readByte("xThumbnail", is, "Not a Valid JPEG File");
061        yThumbnail = readByte("yThumbnail", is, "Not a Valid JPEG File");
062        thumbnailSize = xThumbnail * yThumbnail;
063        if (thumbnailSize > 0) {
064            skipBytes(is, thumbnailSize, "Not a Valid JPEG File: missing thumbnail");
065
066        }
067    }
068
069    @Override
070    public String getDescription() {
071        return "JFIF (" + getSegmentType() + ")";
072    }
073
074}