org.apache.commons.imaging.formats.jpeg.segments.DqtSegment Maven / Gradle / Ivy
/*
* Licensed 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.
* under the License.
*/
package org.apache.commons.imaging.formats.jpeg.segments;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.imaging.ImageReadException;
import static org.apache.commons.imaging.common.BinaryFunctions.*;
public class DqtSegment extends Segment {
public final List quantizationTables = new ArrayList();
public static class QuantizationTable {
public final int precision;
public final int destinationIdentifier;
private final int[] elements;
public QuantizationTable(final int precision, final int destinationIdentifier,
final int[] elements) {
this.precision = precision;
this.destinationIdentifier = destinationIdentifier;
this.elements = elements;
}
/**
* @return the elements
*/
public int[] getElements() {
return elements;
}
}
public DqtSegment(final int marker, final byte[] segmentData)
throws ImageReadException, IOException {
this(marker, segmentData.length, new ByteArrayInputStream(segmentData));
}
public DqtSegment(final int marker, int length, final InputStream is)
throws ImageReadException, IOException {
super(marker, length);
while (length > 0) {
final int precisionAndDestination = readByte(
"QuantizationTablePrecisionAndDestination", is,
"Not a Valid JPEG File");
length--;
final int precision = (precisionAndDestination >> 4) & 0xf;
final int destinationIdentifier = precisionAndDestination & 0xf;
final int[] elements = new int[64];
for (int i = 0; i < 64; i++) {
if (precision == 0) {
elements[i] = 0xff & readByte("QuantizationTableElement",
is, "Not a Valid JPEG File");
length--;
} else if (precision == 1) {
elements[i] = read2Bytes("QuantizationTableElement", is, "Not a Valid JPEG File", getByteOrder());
length -= 2;
} else {
throw new ImageReadException(
"Quantization table precision '" + precision
+ "' is invalid");
}
}
quantizationTables.add(new QuantizationTable(precision,
destinationIdentifier, elements));
}
}
@Override
public String getDescription() {
return "DQT (" + getSegmentType() + ")";
}
}