src/main/java/org/apache/commons/imaging/formats/jpeg/segments/SofnSegment.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.
 */
package org.apache.commons.imaging.formats.jpeg.segments;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.imaging.ImageReadException;
import org.apache.commons.imaging.formats.jpeg.JpegImageParser;

public class SofnSegment extends Segment
{
    public final int width, height;
    public final int numberOfComponents;
    public final int precision;
    public final Component[] components;

    public static class Component
    {
        public final int componentIdentifier;
        public final int horizontalSamplingFactor;
        public final int verticalSamplingFactor;
        public final int quantTabDestSelector;

        public Component(int componentIdentifier,
                int horizontalSamplingFactor,
                int veritcalSamplingFactor,
                int quantTabDestSelector)
        {
            this.componentIdentifier = componentIdentifier;
            this.horizontalSamplingFactor = horizontalSamplingFactor;
            this.verticalSamplingFactor = veritcalSamplingFactor;
            this.quantTabDestSelector = quantTabDestSelector;
        }
    }
    
    public SofnSegment(int marker, byte segmentData[])
            throws ImageReadException, IOException
    {
        this(marker, segmentData.length, new ByteArrayInputStream(segmentData));
    }

    public SofnSegment(int marker, int marker_length, InputStream is)
            throws ImageReadException, IOException
    {
        super(marker, marker_length);

        if (getDebug())
            System.out.println("SOF0Segment marker_length: " + marker_length);

        precision = readByte("Data_precision", is, "Not a Valid JPEG File");
        height = read2Bytes("Image_height", is, "Not a Valid JPEG File");
        width = read2Bytes("Image_Width", is, "Not a Valid JPEG File");
        numberOfComponents = readByte("Number_of_components", is,
                "Not a Valid JPEG File");
        components = new Component[numberOfComponents];
        for (int i = 0; i < numberOfComponents; i++)
        {
            int componentIdentifier = readByte("ComponentIdentifier", is,
                    "Not a Valid JPEG File");

            int hvSamplingFactors = readByte("SamplingFactors", is,
                    "Not a Valid JPEG File");
            int horizontalSamplingFactor = (hvSamplingFactors >> 4) & 0xf;
            int verticalSamplingFactor = hvSamplingFactors & 0xf;
            int quantTabDestSelector = readByte("QuantTabDestSel", is,
                    "Not a Valid JPEG File");
            components[i] = new Component(componentIdentifier,
                        horizontalSamplingFactor, verticalSamplingFactor,
                        quantTabDestSelector);
        }

        if (getDebug())
            System.out.println("");
    }

    @Override
    public String getDescription()
    {
        return "SOFN (SOF" + (marker - JpegImageParser.SOF0Marker) + ") ("
                + getSegmentType() + ")";
    }

}