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.ImageReadException;
029import org.apache.commons.imaging.formats.jpeg.JpegConstants;
030
031public class JfifSegment extends Segment {
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    @Override
043    public String getDescription() {
044        return "JFIF (" + getSegmentType() + ")";
045    }
046
047    public JfifSegment(final int marker, final byte[] segmentData)
048            throws ImageReadException, IOException {
049        this(marker, segmentData.length, new ByteArrayInputStream(segmentData));
050    }
051
052    public JfifSegment(final int marker, final int markerLength, final InputStream is)
053            throws ImageReadException, IOException {
054        super(marker, markerLength);
055
056        final byte[] signature = readBytes(is, JpegConstants.JFIF0_SIGNATURE.size());
057        if (!JpegConstants.JFIF0_SIGNATURE.equals(signature)
058                && !JpegConstants.JFIF0_SIGNATURE_ALTERNATIVE.equals(signature)) {
059            throw new ImageReadException(
060                    "Not a Valid JPEG File: missing JFIF string");
061        }
062
063        jfifMajorVersion = readByte("JFIF_major_version", is,
064                "Not a Valid JPEG File");
065        jfifMinorVersion = readByte("JFIF_minor_version", is,
066                "Not a Valid JPEG File");
067        densityUnits = readByte("density_units", is, "Not a Valid JPEG File");
068        xDensity = read2Bytes("x_density", is, "Not a Valid JPEG File", getByteOrder());
069        yDensity = read2Bytes("y_density", is, "Not a Valid JPEG File", getByteOrder());
070
071        xThumbnail = readByte("x_thumbnail", is, "Not a Valid JPEG File");
072        yThumbnail = readByte("y_thumbnail", is, "Not a Valid JPEG File");
073        thumbnailSize = xThumbnail * yThumbnail;
074        if (thumbnailSize > 0) {
075            skipBytes(is, thumbnailSize,
076                    "Not a Valid JPEG File: missing thumbnail");
077
078        }
079    }
080
081}