    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;
    021
    022import java.io.ByteArrayInputStream;
    023import java.io.IOException;
    024import java.io.InputStream;
    025import java.util.logging.Level;
    026import java.util.logging.Logger;
    027
    028import org.apache.commons.imaging.ImageReadException;
    029import org.apache.commons.imaging.formats.jpeg.JpegConstants;
    030
    031public class SofnSegment extends Segment {
    032
    033    private static final Logger LOGGER = Logger.getLogger(SofnSegment.class.getName());
    034
    035    public final int width;
    036    public final int height;
    037    public final int numberOfComponents;
    038    public final int precision;
    039    private final Component[] components;
    040
    041    public static class Component {
    042        public final int componentIdentifier;
    043        public final int horizontalSamplingFactor;
    044        public final int verticalSamplingFactor;
    045        public final int quantTabDestSelector;
    046
    047        public Component(final int componentIdentifier, final int horizontalSamplingFactor,
    048                final int veritcalSamplingFactor, final int quantTabDestSelector) {
    049            this.componentIdentifier = componentIdentifier;
    050            this.horizontalSamplingFactor = horizontalSamplingFactor;
    051            this.verticalSamplingFactor = veritcalSamplingFactor;
    052            this.quantTabDestSelector = quantTabDestSelector;
    053        }
    054    }
    055
    056    public SofnSegment(final int marker, final byte[] segmentData) throws IOException, ImageReadException {
    057        this(marker, segmentData.length, new ByteArrayInputStream(segmentData));
    058    }
    059
    060    public SofnSegment(final int marker, final int markerLength, final InputStream is)
    061            throws IOException, ImageReadException {
    062        super(marker, markerLength);
    063
    064        if (LOGGER.isLoggable(Level.FINEST)) {
    065            LOGGER.finest("SOF0Segment marker_length: " + markerLength);
    066        }
    067
    068        precision = readByte("Data_precision", is, "Not a Valid JPEG File");
    069        height = read2Bytes("Image_height", is, "Not a Valid JPEG File", getByteOrder());
    070        width = read2Bytes("Image_Width", is, "Not a Valid JPEG File", getByteOrder());
    071        numberOfComponents = readByte("Number_of_components", is,
    072                "Not a Valid JPEG File");
    073        if (numberOfComponents < 0) {
    074            throw new ImageReadException("The number of components in a SOF0Segment cannot be less than 0!");
    075        }
    076        components = new Component[numberOfComponents];
    077        for (int i = 0; i < numberOfComponents; i++) {
    078            final int componentIdentifier = readByte("ComponentIdentifier", is,
    079                    "Not a Valid JPEG File");
    080
    081            final int hvSamplingFactors = readByte("SamplingFactors", is,
    082                    "Not a Valid JPEG File");
    083            final int horizontalSamplingFactor = (hvSamplingFactors >> 4) & 0xf;
    084            final int verticalSamplingFactor = hvSamplingFactors & 0xf;
    085            final int quantTabDestSelector = readByte("QuantTabDestSel", is,
    086                    "Not a Valid JPEG File");
    087            components[i] = new Component(componentIdentifier,
    088                    horizontalSamplingFactor, verticalSamplingFactor,
    089                    quantTabDestSelector);
    090        }
    091    }
    092
    093    /**
    094     * Returns a copy of all the components.
    095     * @return the components
    096     */
    097    public Component[] getComponents() {
    098        return components.clone();
    099    }
    100
    101    /**
    102     * Returns the component at the specified index.
    103     * @param index the array index
    104     * @return the component
    105     */
    106    public Component getComponents(final int index) {
    107        return components[index];
    108    }
    109
    110
    111    @Override
    112    public String getDescription() {
    113        return "SOFN (SOF" + (marker - JpegConstants.SOF0_MARKER) + ") ("
    114                + getSegmentType() + ")";
    115    }
    116
    117}